Zago - Essential US For Trauma - E-FAST [PDF]

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Ultrasound for Acute Care Surgeons Series Editor: Mauro Zago

Mauro Zago Editor

Essential US for Trauma: E-FAST

Mauro Zago Editor

Essential US for Trauma: E-FAST

Editor Mauro Zago, MD General Surgery Department Minimally Invasive Surgery Unit Policlinico San Pietro Bergamo Italy

ISBN 978-88-470-5273-4 ISBN 978-88-470-5274-1 DOI 10.1007/978-88-470-5274-1 Springer Milan Heidelberg New York Dordrecht London

(eBook)

Library of Congress Control Number: 2014939932 © Springer-Verlag Italia 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher's location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

To my five darlings

Foreword

Life-and-death situations make trauma surgery one of the most important medical specialties. In their everyday work, surgeons see the most varied aspects of traumatology. Nonetheless, only those few surgeons who deal with major trauma on a daily basis have the necessary know-how and skills to save the severely injured patient from permanent disability or death. There has been one positive spin-off from the many wars that have been waged in the past centuries: much of what surgeons have learned on the battlefield has come to benefit civil traumatology. It is not enough to be a good surgeon with excellent technique. If lives are to be saved, possible fatal injuries must be recognized at once and dealt with without delay. The surgeon’s first-line technical resource is radiodiagnostics. The choice of diagnostic modality will depend on the injury mechanism, the injuries to be expected therefrom, and finally the patient’s hemodynamic situation. An ultrasound study will almost always be made. In the hands of the surgeon, this is one of the most valuable tools for decision-making. Depending on the patient’s stability, a survey can be made of organ injuries and the presence of blood in the peritoneal space, pleural cavity, and pericardium diagnosed whereby all of these findings can contribute importantly to the right decision. Ultrasound (US) is the most used imaging technology, and this book provides important perspectives on its use in trauma. It is written by experts to provide suggestions, tips, and tricks for the routine clinical use of US. The sonographic anatomy of the thoracic and abdominal organs is presented clearly and understandably. In each chapter, care has been taken to show not just the normal situation but also abnormal images. The truth of the saying that “one picture is worth a thousand words” is proven many times over in the clinical scenarios. The E-FAST protocol and the algorithm for sonography in visceral trauma are new milestones in trauma diagnostics. Not to be forgotten is contrast-enhanced ultrasound (CEUS), which is opening new horizons and becoming increasingly popular. In 2004, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published international guidelines for the use of US contrast media. Echo enhancement with CEUS has significantly improved the sensitivity of detection and visualization of solid organ injuries. CEUS has its very important advantages over CT and MRI with their risks and contraindications (among them exposure to radiation, thyrotoxicosis, kidney failure, and anaphylactic shock), loss of time, far greater expense, and lack of vii

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availability in many hospitals. CEUS is now recommended in addition to FAST in the evaluation and follow-up of traumatic solid organ injuries in stable patients. Mauro Zago, the editor, took the initiative to create this first volume in a series devoted to US in routine clinical use in all forms of acute care surgery. This pocket companion for trauma is intended to help the surgeon performing US in critical situations to make quicker and better assessments and decisions. Dr. Zago and his contributing authors deserve great thanks for sharing with the reader their knowledge and their immense experience with ultrasound diagnostics in trauma. Selman Uranüs, MD, FACS Department of Surgery Medical University of Graz Austria European Society for Trauma and Emergency Surgery (ESTES) – Past President International Association for Trauma Surgery and Intensive Care (IATSIC) – Past President

Preface

Welcome to this first issue of the new Springer series, Ultrasound for Acute Care Surgeons. Ultrasound has a well-established diagnostic role in many surgical diseases, and for specific applications (for instance, breast, liver, and vascular surgery), and is carried out by the surgeons themselves. In the acute setting, however, it is still not the norm for the surgeon to perform ultrasound. This is a situation that needs to be addressed, as clinical point-of-care ultrasound frequently assists in the prompt and appropriate decision-making so important in emergencies. The series is not intended to “reinvent the wheel”; rather, it simply aims to provide surgeons with an additional and, in many respects, extraordinary tool that improves the making of critical (time- and resource-dependent) decisions in numerous clinical situations confronted in daily practice. The practical design of each volume in the series is intended to ensure that no time is lost during consultation. If you are already trained in ultrasound but have limited experience in this specific application, you will be able to rapidly review technical points, profit from the described tricks and tips, and go deeper in the clinical chapters. If you are a beginner, trust that learning E-FAST is the easiest way to gain confidence with ultrasound and you will rapidly ask to learn more and more ultrasound applications. If you are not personally interested in applying ultrasound but are convinced that you must understand the role of E-FAST, you are a smart doctor, and this book is for you, too. Sections that at first glance might appear rather technical or boring, such as those describing knobology or scanning techniques, deserve also to be read by the doctor already trained in ultrasound. Here, technique is rendered clinically relevant. Furthermore, every effort has been made to facilitate comprehension and to allow readers to avoid common mistakes and profit from the authors’ years of experience in the specific field of trauma ultrasound. Nothing can replace a formal practical course followed by proctored practice. However, this book will serve as an ideal quick reference for your personal training: it will increase your confidence in the use of ultrasound faster than might be expected. The expertise of the authors and the efforts they have expended in ensuring that this is a very practical book deserve to be highlighted, and I personally thank all of

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them. Finally, special thanks are due to the editorial staff of Springer: they are a marvelous team, providing invaluable support and maintaining immense patience with the editor. Bergamo, Italy

Mauro Zago

Contents

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Basic Ultrasound Physics, Instrumentation, and Knobology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fikri M. Abu-Zidan

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Introduction and Focused Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . Mauro Zago

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Abdominal Views: Technique, Anatomy, Abnormal Images, Scanning Tips, and Tricks . . . . . . . . . . . . . . . . . . . Fernando Ferreira, Eva T. Barbosa, and António R. Silva

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Thoracic Views: Anatomy, Techniques, Scanning Tips and Tricks, Abnormal Images . . . . . . . . . . . . . . . . . . . . Andrea A. Casamassima and Mauro Zago

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Including EFAST in Trauma Algorithms: When? What Now? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diego Mariani and Mauro Zago

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The Role of EFAST in a Comprehensive US Trauma Management (ABCDE-US): Facing with Clinical Scenarios. . . . . . . . Mauro Zago and Diego Mariani

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Prehospital Ultrasound in Trauma: Role and Tips. . . . . . . . . . . . . . . . Miriam Ruesseler

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CEUS: What Is It? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Massimo Valentino, Libero Barozzi, and Cristina Rossi

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Basic Ultrasound Physics, Instrumentation, and Knobology Fikri M. Abu-Zidan

1.1

Introduction

Using ultrasound in life-threatening conditions is one of the successful stories of carrying portable technology to sick patients so as to improve outcome of their management. The value of ultrasound will be optimized only after understanding its limitations and pitfalls. This cannot be achieved without understanding basic ultrasound physics. This chapter will present basic physics in a simple way that is relevant to clinicians who are keen to start using ultrasound in their clinical practice. Practical issues will be explained without going into details.

1.2

Basic Ultrasound Physics

Ultrasound is a sound wave having a frequency higher than 20,000 Hz, which is above the range of human hearing. It is a type of energy that can transmit through air, fluid, and solid material. Medical ultrasound machines generate ultrasound waves and receive the reflected echoes. B mode (brightness mode), which gives black and white images, is the basic mode that is usually used in trauma patients. The sound waves are emitted from piezoelectric crystals from the ultrasound transducer. As ultrasound waves pass through various body tissues, they are reflected back to the transducer creating an image on the monitor. The resistance to propagation of ultrasound waves (acoustic impedance) will vary depending on the density of material particles. As the material gets more solid, the particles will become denser. The denser the material is, the more it reflects the sonographic waves (Fig. 1.1). Fluid transmits sound waves and has less waves reflected back. This

F.M. Abu-Zidan, MD, FRCS, FACS, PhD, DipApplStats Department of Surgery, Faculty of Medicine and Health Sciences, UAE University, 17666, Al-Ain, United Arab Emirates e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_1, © Springer-Verlag Italia 2014

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D L

Fig. 1.1 The denser the material is, the more it reflects the sonographic waves. Fluid [like bile in the gallbladder (GB)] transmits sound waves and has minimum waves reflected back. This yields a black “anechogenic” image. Stones (S) yield white images with a shadow behind them. Soft tissues, like the liver (L), yield different gray color scales. Fibrous tissue like the diaphragm will be white without a shadow (D)

yields a black “anechogenic” or “anechoic” image. Other tissues have varying levels of echogenicity. Stones, bones, and calcifications yield the brightest “white” images and a shadow behind them. Between these two extremes, other tissues can be outlined and identified within the gray scale (Fig. 1.2). Fibrous tissue like the diaphragm or capsule of the kidney will be white without a shadow. Air is a strong ultrasound beam reflector. It scatters the ultrasonic waves and prevents transmission to deeper structures. That is why it is difficult to see behind subcutaneous emphysema in a trauma patient.

1.3

Ultrasound Transducers

Transducers contain piezoelectric crystals that emit ultrasound. There are different factors that can control the way these ultrasound waves are sent: 1. Continuity: Emission of ultrasound waves can be either interrupted or continuous. Emission of ultrasound waves as pulses will have two periods: a period in which the pulse is sent and another period in which reflected waves are received to generate brightness (B) mode images. Continuous emission of ultrasound waves is used for the Doppler mode. 2. Frequency: By modifying the frequency in which waves are sent, it is possible to have different applications controlling mainly the depth and resolution of the images. Frequency and resolution have an inverse relationship. The lower

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L GB

D IVC

Fig. 1.2 Ultrasound of the right upper quadrant in a patient complaining of right upper quadrant pain to demonstrate acoustic impedance. The gallbladder (GB) and IVC contain fluid which is black. The liver (L) is a soft tissue and is gray in color. The diaphragm (D) is a fibrous tissue which is white without a shadow, and a gallstone which is a solid structure (arrow head) is white with a posterior acoustic shadow (small arrows)

frequency is, the poorer the image resolution, but the greater the depth of wave penetration. Higher frequency probes have less depth penetration but have the advantage of higher resolution. The transducer frequencies commonly used for abdominal exam are between 2.5 and 5 MHz. This implies that for obese patients and deep structures, probes of low frequencies should be used. In contrast, probes of high frequency (10–12 MHz) should be used for superficial structures. 3. Shape of the surface of the probe: Ultrasound waves are sent vertical to the surface of the probe. By curving the surface, it is possible to widen the area of the studied field. It is understandable that the lateral resolution in the deeper structures will be less when using this type of probes. Lateral resolution is the ability of ultrasound to differentiate between two objects located perpendicular to the ultrasound beam. These probes are called convex array probes (Fig. 1.3). When the surface is kept flat, the waves will be parallel with each other, and the lateral resolution will be much better. These are called linear array probes. These probes usually have high frequencies of 10–12 MHZ indicating that their penetration is less than others, but they have excellent resolution. That is why the shape of the

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Convex array

Linear array

Phased array

Fig. 1.3 Changing the shape of the surface of the probe and its size has resulted in different types for different applications

image of the linear array probe is rectangular compared with the convex array probe images which will be wider in the area located away from the probe. 4. Surface area of the probe: It is important to have no barrier between the studied structures and the ultrasound waves. For example, the ribs will not permit ultrasound waves to pass through them when imaging intrathoracic structures through the thoracic wall and will have a shadow behind them. The phased array probe has a small surface that will enable the examiner to visualize the heart between the ribs (Fig. 1.3). 5. Orientation of the probe: Each piezoelectric crystal in the probe is represented on specific points on the screen. Each probe will have a marker to identify a specific side of the probe. The operator should know the probe side before starting any diagnostic or interventional procedure. This side should be confirmed practically by putting gel on the surface and moving the index finger on it to see which side it represents. It is advisable as agreed standard to have the marker that represents the right side of the screen upward toward the head of the patient in the sagittal or coronal sections (Fig. 1.4) and to the right side of the patient in transverse sections (Fig. 1.5). This will save time as emergency physicians will do both abdominal and thoracic images in emergency conditions and there is no time to change the setting. The rule of thumb is that “the right side of the patient should be on the right side of the screen.”

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Sagital section

U D

U

D

Fig. 1.4 Sagittal section of the abdominal examination. The probe marker (arrow) should point upward. The upper part of the abdomen (U) should be to the right side of the screen. U upward or proximal, D down or distal

Transverse section

R

L

L R

Fig. 1.5 Transverse section of the abdominal examination. The probe marker (arrow) should point to the right. The right part of the body (R) should be to the right side of the screen. R right, L left

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Fig. 1.6 A schematic diagram demonstrating different sonographic images produced when the body is sliced by ultrasound at different planes

6. Slicing the body to get images: It is important to appreciate that the B mode is a twodimensional (2D) section that depends on the anatomical site of the slice. The body can be sliced at different planes depending on the position of the probe. Sections can be sagittal, coronal, transverse, or oblique. These thin slices are of less than 1 mm each. This implies that we are visualizing only a thin section of the body. Figure 1.6 demonstrates this principle. If the gallbladder shown in this image is sectioned vertically, then it will appear as a single cavity. If it is transected transversely on the plane shown in Fig. 1.6, then it will appear as two cavities and possibly misinterpreted as an intraperitoneal collection. If the transverse planes are moved to be more proximal, then it will be appreciated that this is a continuous cavity. The fan-shaped movement is a very useful technique to obtain images by using different angles to slice the body while keeping the probe at the same point. This movement can be horizontal as shown in Fig. 1.7 or vertical.

Tips and Tricks

1. Choose the proper transducer depending on the indication and patient’s age and built. 2. Use plenty of ultrasound gel to have proper contact between the transducer and skin. 3. Check the orientation and side of the transducer. 4. Optimize the gain and depth of the image. 5. Use the fan-shaped movement gently.

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Fan shaped movement

Fig. 1.7 Horizontal fan-shaped movement used to obtain sonographic images by changing the angles in which the body is sliced while keeping the probe at the same point

1.4

Knobology

There are basic buttons that a beginner user of point-of-care ultrasound should know (Fig. 1.8). These include: 1. On/off button: Ultrasound machines with rapid boot-up are more desirable because the machine should be moved quickly between patients especially in mass casualty situations. Long boot-up time may become problematic in this situation. 2. The gain setting: The gain is the amplification of the received ultrasound signal. When the overall gain knob is turned to the right side, the received signal is magnified and more received signals are allowed to be processed. The ultrasound image will become brighter and vice versa (Fig. 1.9). Time gain compensation (TGC) will change the gain factor so that equally reflective structures will be displayed with the same brightness regardless of their depth. Try to overuse/ underuse gain and TGC at different depths to easily understand the meaning of a right regulation. 3. The image depth: It is always advised to have a deeper depth than needed and then gradually reduce it to cover the area of interest. One of the pitfalls is to use a shallow depth missing deeper important sonographic findings. 4. The mode buttons: These buttons will select the mode of ultrasound waves. Brightness mode (B mode) is the basic mode that is usually used. The B mode gives a two-dimensional (2D) black and white image. Imaging one line over time is called the moving mode (M mode).

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On/off

TGC Freeze Depth

Mode B

Caliper

M Gain

Measure

Fig. 1.8 Basic buttons of a portable ultrasound machine that a beginner user of point-of-care ultrasound should know

Gain

Fig. 1.9 The ultrasound image will become brighter when the gain is increased

5. The freeze button: This freezes the image so that certain structures can be measured, saved, or printed. When turned off, the real-time continuous display of images is turned on. 6. The caliper and measurement buttons: These buttons will generate point markers on the frozen image to define distances of interest that can be measured.

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Pitfalls

1. Having a wrong orientation of the transducer especially when performing interventional ultrasound. 2. Using high gain when looking for pelvic fluid in Douglas pouch. 3. Starting with superficial limited depth when looking for deep intraperitoneal fluid. 4. Judging quickly that a B mode study is negative. B mode is only a two-dimensional image of less than 1 mm thick. You should have a threedimensional orientation.

1.5

Ultrasound Artifacts

The operator should be especially knowledgeable of the sonographic artifacts that can mislead him/her. Nevertheless, some artifacts are useful for diagnosing different conditions. The most common artifacts seen are as follows. Shadow artifact and posterior enhancement: Ultrasound will not be able to image what is behind a solid structure (like the ribs) causing a shadow artifact (Fig. 1.10). The shadow artifact is occasionally useful, for example, in detecting Shadows

S

Liver S

Fig. 1.10 Ultrasound will not be able to image what is behind a solid structure like the rib. This will cause a shadow artifact (S) behind the ribs

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F.M. Abu-Zidan Posterior enhancement

Liver GB

Fig. 1.11 Gallstones within the gallbladder (GB) causing shadow artifact behind them. The posterior enhancement is shown on both sides of the shadow artifact

Edge artifact

Urinary bladder

Fig. 1.12 Edge artifact caused by refraction of the ultrasound at the edge of the urinary bladder

gallstones (Fig. 1.11). The posterior enhancement may occur when imaging fluidfilled structures. More ultrasound waves will penetrate fluid-filled structures, like the gallbladder and urinary bladder, and a white enhancement area will appear behind them compared with adjacent tissues. Small amount of pelvic fluid can be missed in Douglas Pouch if the gain was high. It is important to use the proper gain once looking for pelvic fluid, otherwise it can be missed. Edge artifact: The edge artifact occurs when a beam of ultrasound refracts at the edge of a rounded structure like the urinary bladder and kidney (Fig. 1.12). This

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Mirror plane

Urinary bladder

Mirror artifact

Fig. 1.13 Sagittal section of the pelvis showing a mirror artifact of the urinary bladder mimicking a fluid collection

should not be misinterpreted as intraperitoneal fluid. This artifact will change by changing the angle of the probe. Mirror artifact: High acoustic impedance tissues like the diaphragm or the pelvic floor work like a mirror reflecting sonographic waves by an angle. Similar to a real mirror, the mirror artifact will show as a virtual object (Fig. 1.13). The mirror effect is a normal artifact in RUQ view: it disappears in case of pleural effusion. Ultrasound artifacts are useful in diagnosing gall stones (Fig. 1.2) and in showing the normal sonographic lung characteristics (Fig. 1.14). Reverberation artifact: Reverberation artifact occurs when ultrasound bounces between two interfaces, especially with high acoustic impedance like the pleura. The waves will move forward and backward between these interfaces. The machine will recognize these waves as parallel lines with equal distances between them and decreased density for the deeper lines, because the reflected waves become gradually less (Fig. 1.14). 1. You should be careful not to interpret the mirror artifact of the urinary bladder as a pelvic fluid. 2. You should be careful not to interpret a rib shadow or edge artifact as intraperitoneal fluid. In summary the operator should be familiar with basic physics of ultrasound and know their ultrasound machine, the type of probes used, how to control its outcome, and, more importantly, how to correlate sonographic findings with clinical findings so as to maximize ultrasound benefit.

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Fig. 1.14 Reverberation artifact of the lung occurs as ultrasound waves bounce between the transducer and the pleura (head arrow). The reverberation lines (arrows) are called A lines, representing “repetition” of the pleural line. The distances between these lines are equal

Remember!

• “The right side of the patient on the right side of the screen” (transversal) • “The upper part of the patient on the right side of the screen” (sagittal or coronal) • The key buttons of an US machine are (fill yourself – look at pages 7 and 8 of this chapter) 1. _______________________________ 2. ___________& TGC _____________ 3. ______________________________ 4. __B-________/ -mode____________ 5. ____________________________ 6. ______________________________ • Artifacts are not always enemies

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Suggested Reading 1. Feldman MK, Katyal S, Blackwood MS (2009) US artifacts. Radiographics 29:1179–1189 2. Hangiandreou NJ (2003) AAPM/RSNA physics tutorial for residents. Topics in US: B-mode US: basic concepts and new technology. Radiographics 23:1019–1033 3. Lichtenstein DA (2010) Basic notions in critical ultrasound. In: Lichtenstein DA (ed) Whole body ultrasonography in the critically ill. Springer, New York, pp 3–10 4. Muglia V, Cooperberg PL (1998) Artifacts. In: McGahan JP, Goldberg BB (eds) Diagnostic ultrasound, a logical approach. Lippincott-Raven Publishers, Philadelphia, pp 21–37 5. Rose JS (1997) Ultrasound physics and knobology. In: Simon BC, Snoey ER (eds) Ultrasound in emergency and ambulatory medicine. Mosby-Year book Inc., St Louis, pp 10–38 6. Rose JS, Bair AE (2006) Fundamentals of ultrasound. In: Cosby KS, Kendall JL (eds) Practical guide to emergency ultrasound. Lippincott Williams and Wilkins, Philadelphia, pp 27–41 7. Schuler A (2008) Image artifacts and pitfalls. In: Mathis G (ed) Chest sonography, 2nd edn. Springer, New York, pp 175–182 8. Wells PNT (1998) Physics and bioeffects. In: McGahan JP, Goldberg BB (eds) Diagnostic ultrasound, a logical approach. Lippincott-Raven Publishers, Philadelphia, pp 1–19 9. Whittingham TA (2007) Medical diagnostic applications and sources. Prog Biophys Mol Biol 93:84–110

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Introduction and Focused Questions Mauro Zago

EFAST (extended focused assessment by sonography for trauma) represents the basic US approach to trauma patient. Its role in trauma management algorithm is evolving over the years and depends from many factors: • Standardized and agreed institutional (not those found in literature) protocols including focused US • Trained surgeons/physicians in the team available and able 24/7 to perform US • Local resources • Different settings (prehospital, in-hospital, austere environment, etc.) • Local “political” constraints and resistance to the use of US by non-radiologists If you are reading this book, you are certainly convinced of US being an invaluable tool for you in a context of quick decision-making. You want to know how to do it and how to use the findings you get on the screen, in both major and minor trauma. Before going through technical points, learning how to perform and to better include this exam in the management of your patients, remember you should ask EFAST for a few focused questions in order to benefit from a technologic “third hand.” The first questions are not specifically about US.

• How is the physiology of my patient? And anatomy? • Does my patient require US? • Could I better understand/anticipate physiologic derangements in this patient by EFAST?

M. Zago, MD General Surgery Department, Minimally Invasive Surgery Unit, Policlinico San Pietro, Bergamo, Italy e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_2, © Springer-Verlag Italia 2014

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Doubting the appropriateness of US might be surprising in a US manual, but indeed in major trauma patients even a few minutes are lifesaving, and all procedures that are not strictly necessary should be avoided, unless they could really change the clinical decision. Any flow chart should start from the patient physiology and not from the US findings. The immediate identification of the so-called hemodynamic instability is a clinical prerequisite. It is an information you can get in a few seconds (RTS score, on the scene hypotension, vital parameters on road and at arrival, etc.), and anticipates the following steps if damage control resuscitation is required. We recommend you to be excessively careful in starting by this key point. Sort the US probe from your pocket immediately after. Finally, you have the probe in your hands. Your aim is to identify free fluid and air and to correlate the US findings with the patient status. You must first discover signs of two main killers: hemorrhage and pneumothorax.

• Is there free fluid in the abdomen? • Is there free fluid in the thorax? • Is there free air in the chest?

Yes ◻ Yes ◻ Yes ◻

No ◻ No ◻ No ◻

Simple questions, simple binary answers! Wherever and whenever during the primary and secondary survey, the EFAST exam is for answering only these questions. Every other adjunctive finding observed on the screen (for instance, dishomogeneous spleen suspected for rupture) could be for sure “taken into account,” but we cannot forget to remain simple in the reasoning. This is the only way to be adherent to the master law: “clinical decision before definitive diagnosis.” The three EFAST key questions depicted in the box above help you in answering the basic clinical questions: becomes. Is there • • • • •

A hemoperitoneum? A hemothorax? A pericardial effusion? Is it a cardiac tamponade? A pneumothorax? Do the US findings correlate with the patient status?

In other words, you need to understand, for example, if the amount of blood you found in the abdomen justifies the shock in your patient. You might assess it using simple scores.

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Or you would like to quickly answer to the following questions: • Hemorrhagic? → Where? • Nonhemorrhagic? → Where is the cause of shock? EFAST is an effective tool for ruling in/ruling out some of the hemorrhagic/ nonhemorrhagic causes of shock: hemoperitoneum, hemothorax, tension pneumothorax (if not already clinically detected and treated), and cardiac tamponade. Imagine a less emergent situation: a young female sustained a blunt abdominal trauma, she is hemodynamically normal and stable, and you found a little amount of fluid in the abdomen. There is a slight abdominal pain in the RLQ on physical examination. CT (when available) showed no solid organ injuries and minimal amount of fluid in right iliac fossa. “Might it may be a hollow viscus lesion or not? Operation? Observation? Literature allows both options….” Could US help you? Maybe yes, with a US-guided diagnostic peritoneal aspiration (DPA): • Bile → Operation • Blood → It depends! • Clear fluid → Physiologic peritoneal fluid in childbearing age females In other chapters (Algorithms), you will find some examples of US-driven suggested management of trauma cases and test yourself. EFAST has certainly some limits and pitfalls, and it really not always solves the problem: be aware about that, go ahead with your clinical reasoning like as you don’t have US, and ask your team and if needed for a help! Having clear questions in mind is mandatory for getting the best clinical result from EFAST. Your US performance is important, but more important is to take the right clinical decision: that is why you have decided to read this book! Frequently, “unsatisfactory” or “doubtful” exams can help your decision-making process. Even in more advanced application of US in trauma patients (ABCDE-FAST, interventional maneuvers, monitoring of shock, CEUS-FAST, etc.), surgeon should always ask himself/herself if and what US can add to decision-making process: Can US help me? Can US shorten the time to definitive treatment? Can US change my diagnostic algorithm?

Remember!

• • • •

Assess physiology and anatomy first Basic US questions (liquid? air?) Clear clinical questions (according to the patient status) Link EFAST findings to your clinical reasoning

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Abdominal Views: Technique, Anatomy, Abnormal Images, Scanning Tips, and Tricks Fernando Ferreira, Eva T. Barbosa, and António R. Silva

3.1

Introduction

Trauma care has evolved all over the world with more efficient integrated emergency medical systems. Many of these systems are achieving lower mortality rates comparatively to the past because of expeditious trauma management that starts immediately on scene all the way to the trauma resuscitation bay often extending into the operating room. The approach to these patients requires dedicated surgeons that must determine the extent of injuries in minutes with E-FAST (extended focused assessment with sonography for trauma) and decide if a patient is bleeding and from which body compartment. This may diminish time to definitive care (operating/angiography suite) with possible improvements in length of stay, lower cost of hospitalization, morbidity, and mortality if definitive surgical trauma care (DSTC) is accordingly executed. E-FAST is most useful in the emergency room for the patient who is too hemodynamically unstable to perform a CT exam. This modality has proven to decrease the number of nontherapeutic laparotomies because it decreases the need for a

F. Ferreira, MD (*) Emergency and Trauma Surgery, Upper Gastrointestinal Surgery Unit, Department of Surgery, U.L.S. – Matosinhos, E.P.E., Pedro Hispano Hospital, Rua Dr. Eduardo Torres, Senhora da Hora 4464-513, Portugal The Faculty of Medicine, University of Oporto, Porto, Portugal e-mail: [email protected] E.T. Barbosa, MD, MSc • A.R. Silva, MD Emergency and Trauma Surgery, Colorectal Surgery Unit, Department of Surgery, U.L.S. – Matosinhos, E.P.E., Pedro Hispano Hospital, Rua Dr. Eduardo Torres, Senhora da Hora 4464-513, Portugal The Faculty of Medicine, University of Oporto, Porto, Portugal e-mail: [email protected]; [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_3, © Springer-Verlag Italia 2014

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diagnostic peritoneal lavage and its false positives. It is the modality of choice in shock evaluation in Advanced Trauma Life Support (ATLS™) and DSTC™ protocols for trauma management. One should never forget to repeat an E-FAST exam after a few minutes placing the patient in reverse Trendelenburg for the pericardial view and regular Trendelenburg to scan the abdomen if the patient shows any sign of shock despite resuscitation. You must also repeat the primary assessment and exclude all other types of shock. It is important for the surgeon to integrate E-FAST into the evaluation protocol to help determine any indication for a trauma laparotomy and/or thoracotomy. This chapter will aid the surgeon in understanding E-FAST as a powerful diagnostic modality by reviewing the following aspects: • Scanning technique – How to scan – Normal anatomy – Basic abnormal findings (what to search) and the clinical meaning • Scanning tips and tricks

3.2

Scanning Technique

3.2.1

How to Scan

The main objective of performing focused ultrasound is to detect blood in areas where it should not exist. E-FAST views involve thoracic views discussed previously and the abdominal views of the 4 P’s (pericardial, perihepatic, perisplenic, and pelvic) (Fig. 3.1). Recent bleeding is represented by an anechoic “dark line” in these spaces, yet older blood may have a heterogeneous echogenicity owing to clots. Attaining E-FAST views requires basic knowledge of ultrasound physics and knobology of ultrasound machines. We prefer the use of curved probes with a frequency between 3 and 5 MHz. Optimal depth settings will depend on patient body habitus, but a setting of 8–15 cm is usually sufficient. Adjust gain settings in a way that blood vessels are black and the surrounding tissues are not too bright. Hold the probe like you hold a pen or a pencil. Grasp it with the first three fingers of the dominant hand, and use the remaining fingers to stabilize the probe touching the patient if needed avoiding inadequate pressure. Do not forget the basic transducer movements known as ART (alignment for sliding movements, rotation, and tilting). The patient must be in a supine position, and the operator should stand to the right. According to international ultrasound consensus, the transverse view of our patients is a perspective from the feet (Fig. 3.2). Therefore, the images on the right of the patient should show on the left of the monitor. The sagittal and coronal views also corresponds to an image on the left of the monitor which corresponds to the cranial direction (Fig. 3.3). The scanning probe has a marker on the probe which

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Fig. 3.1 The four scanning windows of the E-FAST abdominal examination

helps keep the proper orientation as referred. One can also assure this by pressing on the surface of the probe’s marker just to guarantee its correct position by viewing movement on the left side of the monitor. All obtained ultrasound images should be correlated with the clinical situation. Please remember that this type of ultrasound is more focused on a clinical basis rather than the traditional anatomically oriented ultrasound that is performed in the radiology unit.

3.2.2

Normal Anatomy

The order of the E-FAST views is not standardized although many surgeons argue that in cases of thoracic trauma, one should begin with a pericardial view. The perihepatic view may first be performed in abdominal trauma since it is where blood primarily deposits in the peritoneum.

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Fig. 3.2 The ultrasound transverse caudal to cranial view

Pericardial View The subcostal view is also known as subxiphoid; this permits the visualization of the heart as well as part of the liver and diaphragm. Usually, a very small amount of physiological fluid exists between the parietal and visceral pericardium that is noncircumferential and that is rarely seen. The probe should be placed with the pointer directed toward the patient’s right. The convex surface of ultrasound probe should be placed in the midline, angled slightly upward toward the left shoulder, and insinuated under the ribcage to minimize thoracic ribcage shadow, until a view of the heart and left lobe of the liver is obtained (Fig. 3.4). Normal pericardium is seen as a hyperechoic (white) line surrounding the heart below the left lobe of the liver (Figs. 3.5 and 3.6). To enhance imaging ask the patient to bend his knees and hold his breath or make an end-inspiratory pause if on mechanical ventilation. The intercostal or parasternal view is also a valid option if the subcostal view is not adequate owing to obesity, protuberant abdomen, abdominal tenderness, and gas or epigastric lesions.

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Fig. 3.3 Green marker pointing toward the patient’s head in coronal view

Fig. 3.4 Position for pericardial subxiphoid view

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Figs. 3.5 and 3.6 Normal subcostal echocardiographic view

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Fig. 3.7 Position for perihepatic E-FAST view

Perihepatic View The perihepatic or right upper quadrant view permits the surgeon to acquire a partial image of the liver, the right kidney, the subphrenic space, and the right pleural space. The right subcostal technique is obtained with the probe at the right infracostal margin, just lateral to the midclavicular line (Fig. 3.7). Angle the probe until the hepatorenal space (Morison’s pouch) is seen. In a normal view, the liver and kidney are closely aligned separated by a brightly echogenic surface (Gerota’s fascia) (Figs. 3.8 and 3.9). To better visualize the subphrenic space, one should gradually move the probe in a more cranial direction and laterally closer to the posterior clavicular line allowing for a more coronal perspective. Right intercostal oblique or transverse views can be obtained rotating the probe counterclockwise (Fig. 3.10). This allows a better visualization of the right pleural space, Morison’s pouch, and right paracolic gutter. As mentioned, to enhance imaging, have the patient hold his breath or make an end-inspiratory pause if on mechanical ventilation.

Perisplenic View The perisplenic or left upper quadrant view may be considered more challenging since the spleen is smaller and located more posteriorly than the liver. This approach requires that the placement of the probe be intercostal and as close to the posterior axillary line as possible between the 10th and 11th ribs angled to achieve

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Figs. 3.8 and 3.9 Normal view of hepatorenal interface

a view of the spleen, the left kidney, the subphrenic space, and the left pleural space (Figs. 3.11, 3.12, and 3.13). The spleen has a homogeneous cortex that is more echogenic than the left kidney cortex. To better visualize the subphrenic space, one should position the probe marker upward pointing toward the left posterior axilla

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Fig. 3.10 Probe rotation for intercostal view

Fig. 3.11 Position for perisplenic view

and gradually move the probe in a more cranial direction laterally closer to the posterior clavicular line allowing for a more coronal perspective. One should enhance the view of the left diaphragm and spleen by having the patient hold his breath or making an end-inspiratory pause if on mechanical ventilation. This will cause the diaphragm to move into the necessary plane. For a better view of the spleen and lower pole of the kidney, have the patient exhale or make an end-expiratory pause if on mechanical ventilation, thus minimizing interference from the stomach.

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Fig. 3.12 Normal anatomy of splenorenal space with colored spleen and kidney

Fig. 3.13 Anatomy and view of splenorenal space

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Fig. 3.14 Position for pelvic transverse view

Pelvic View The pelvic view should be evaluated in both transverse and sagittal planes. The probe must be placed transversely in the abdominal midline 2–4 cm superior to the symphysis pubis with the probe marker pointing to the patient’s right, angled down until the prostate or vaginal stripe is identified (Fig. 3.14). The probe is then rotated 90° placing the probe marker in a cranial direction and slightly tilting the probe, to avoid interference from the pubic rami, providing a sagittal view of pelvic structures (Fig. 3.15). A full bladder is essential for an adequate scan. The best opportunity to acquire a good sonographic view is before the placement of a urinary Foley. If it has already been placed, one may inject saline into the bladder in a retrograde manner or wait until it fills normally not forgetting to clamp the tube. The pelvic view permits the visualization of the bladder that serves as an acoustic window. In the female it allows for visualization of uterus and the rectouterine pouch and in the male the seminal vesicles, prostate, and rectovesical recess (Figs. 3.16, 3.17, 3.18, and 3.19).

3.2.3

Basic Abnormal Findings (What to Search) and the Clinical Meaning

In the same order as previously presented, we shall review the abnormal findings and the clinical meaning that one should keep in mind when performing an E-FAST examination.

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Fig. 3.15 Position for pelvic sagittal view

Fig. 3.16 Normal pelvic transverse view colored for better identification

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Fig. 3.17 Normal pelvic view as seen in display monitor

Fig. 3.18 Sagittal pelvic view. Colored structures for better visualization

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Fig. 3.19 Normal anatomy of sagittal pelvic view

Heplful Tips

Never forget the basics of ultrasonography such as the use of sufficient amount of gel to facilitate good ultrasound wave transmission and the proper inclination of the probe to avoid interference from any bone structures.

Pericardial View: Subcostal and Parasternal In the E-FAST view, the subcostal window may permit a full four-chamber perspective of the heart. The pericardium is more hyperechoic than the heart muscle. If fluid is present between the parietal and visceral pericardium, this should be identified with high sensitivity as a black line representing an acute bleed; however, in some healthy patients, a small amount of fluid can also be seen in the dependent aspect of the heart, so clinical correlation is always mandatory. A partial pericardial anterior anechoic line may correspond to a pericardial fat strip yet if circumferential will in fact represent pericardial fluid (Fig. 3.20).

Helpful Tips

Be careful with subcutaneous emphysema which can obscure a proper ultrasound view. The transducer should be very angled approximately 5–10° or be flat to the skin.

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Fig. 3.20 Positive pericardial E-FAST

Pericardial fluid may be obscured by a large hemothorax. It is advisable to repeat your scan after chest tube placement. If the subxifoid window is not available try the left parasternal window at 4th or 5th intercostal space.

Perihepatic View The perihepatic or right upper quadrant view allows for a partial view of the liver and right kidney. This permits good visualization of fluid in Morison’s pouch, the right pleural space, and the subphrenic space. If a hemoperitoneum exists, it will appear as an anechoic area in Morison’s pouch and/or the subphrenic space (Fig. 3.21). This free fluid tends to triangulate as it follows the path of least resistance differing from visceral edema, which has a more cylindrical appearance. Morison’s pouch represents a dependent location for blood accumulation. Be aware that the internal fluid in the viscera such as the duodenum, colon, gallbladder, and even the vena cava can be mistaken for free peritoneal fluid.

Helpful Tips

Placing the patient in a Trendenlenburg position will facilitate fluid accumulation at Morison’s pouch.

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Fig. 3.21 Positive perihepatic E-FAST

Be aware that perinephric fat can mimic a hematoma. Perinephric fat is usually symmetric with the opposite kidney. Ascites has an identical appearance and can be mistaken for hemoperitoneum. Liver disease and right heart failure should be considered.

Perisplenic View The perisplenic or left upper quadrant view allows for different perspectives of the spleen, left kidney, and left pleural space. Hemoperitoneum will translate as an anechoic area in the subphrenic space or in the splenorenal recess (Fig. 3.22). The path of least resistance for the peritoneal fluid will most likely extend to the subphrenic space, with overflow going into the splenorenal fossa and eventually across to Morison’s pouch. Pleural fluid, in a trauma context, is most likely a hemothorax being located in the left pleural space and accurately detected on this limited view as an anechoic region above the left hemidiaphragm.

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Fig. 3.22 Positive perisplenic E-FAST

Helpful Tips

Due to gastric distension secondary to opioid medication and hyperventilation, a NG tube placement will permit a better view of the upper left quadrant. Placing a towel under the spine board will allow for a better view of the spleen from a more posterior angle. Stay posteriorly for a better visualization.

Pelvic View: Transversal and Sagittal In a female patient, free fluid appears in the rectouterine pouch with greater amounts of fluid extending around the uterus (Figs. 3.23 and 3.24). In a male patient, this fluid appears in the rectovesical pouch or cephalad to the bladder. In both cases, a significant amount of perivesical fluid, most likely blood in trauma cases, will produce an anechoic medium that accentuates bowel loop underwater undulation.

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Fig. 3.23 Positive pelvic view (transverse)

Fig. 3.24 Positive pelvic view (sagittal)

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Helpful Tips

Fluid within a collapsed bladder may appear as free peritoneal fluid. A full bladder is essential. Seminal vesicles may be incorrectly identified as free fluid in a transverse view. Use a sagittal view and sweep slightly lateral to differentiate. Premenopausal females may normally have a small amount of free fluid in the Pouch of Douglas.

Suggested Reading 1. American College of Surgeons Committee on Trauma (2008) ATLS® student course manual, 8th edn. American College of Surgeons, Chicago 2. Boffard KD (2007) Manual of definitive surgical trauma care, 2nd edn. Edward Arnold Publishers Ltd., London 3. Boulanger BR, Brenneman FD, McLellan BA et al (1999) Prospective evidence of the superiority of a sonography-based algorithm in the assessment of blunt abdominal injury. J Trauma 65:632–637 4. Ihnatsenka B, Boezaart AP (2010) Ultrasound: basic understanding and learning the language. Int J Shoulder Surg 4:55–62 5. Melniker L, Liebner E, McKinney M et al (2006) Randomized clinical trial of point-of-care, limited ultrasonography for trauma in the emergency department: Sonography Outcomes Assessment Program (SOAP) -1 trial. Ann Emerg Med 48:227–235 6. Rozycki GS, Ochsner MG, Feliciano DV et al (1998) Early detection of hemoperitoneum by ultrasound examination of the right upper quadrant: a multicenter study. J Trauma 45:878–880

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Thoracic Views: Anatomy, Techniques, Scanning Tips and Tricks, Abnormal Images Andrea A. Casamassima and Mauro Zago

4.1

Introduction

The idea behind chest ultrasound is not a recent one. The first published paper on the diagnosis of pneumothorax dates back to the 1986 (Rantanen). In the last 15 years, several papers showed the efficacy of chest ultrasound in detecting both pneumothorax (PTX) and hemothorax. Some authors say that US is faster than the fastest of X-rays, and indeed, it can buy you some time just when time is of the essence. In this chapter, you’ll learn how to perform a correct chest ultrasound examination to detect two life-threatening conditions, such as pneumothorax and hemothorax. You will learn to recognize the normal sonographic anatomy of the chest wall as well as normal and pathological US patterns. At the end of this chapter, you’ll be able to answer the same old question (“Is there free fluid?”) and a new one (“Is there free air?”).

Chest US is useful in prehospital and in emergency room but also in intensive care units, to detect PTX and hemothorax earlier than using X-ray and without moving the patient!

A.A. Casamassima, MD (*) Emergency Department, Istituto Clinico Città Studi, Milano, Italy e-mail: [email protected] M. Zago, MD General Surgery Department, Minimally Invasive Surgery Unit, Policlinico San Pietro, Bergamo, Italy e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_4, © Springer-Verlag Italia 2014

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Scanning Technique and Semeiotics

As we said before, there are two main severe conditions possibly affecting a chest trauma patient that can be detected with US: hemothorax and pneumothorax. Let’s talk about hemothorax first as the technique is a natural extension of the abdominal views. You have learned to explore the abdomen in the previous chapter and you may recall the upper right and left quadrant views. Starting from those views, you simply have to pan the probe headward a few inches, along midaxillary/posterior axillary line. That way you will switch from the abdominal to the chest cavity. On the monitor you will see the liver, a bright curved line which is the diaphragm and on the left side of the screen you will have the chest cavity. What you see depends on the condition of the patient. A bright curtain moving synchronously with the breathing cycle stands for a normal finding (Fig. 4.1). The white artifact is the lung (see below): so, if the lung is detectable on mid-/posterior axillary line without any black strip interposition, there is no clinically relevant fluid in the thorax! Another normal finding is the “mirror effect,” an US artifact. Due to the curved surface of the diaphragm, you will happen to see the same texture of the liver above (i.e., on the left side) the diaphragm bright line (Fig. 4.2).

Fig. 4.1 Normal right upper quadrant view. On the left side of the figure, there is the “white curtain” of the lung, descending to cover the texture of the liver

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Fig. 4.2 Mirror effect. On both sides of the diaphragm, you can see the same texture. That indirectly rules out pleural effusion

On left side of the patient, the technique will be the same: upper left abdominal quadrant view, pan headward 1 or 2 in. You will see the spleen, a bright white line (the diaphragm), and the white curtain moving in and out of the screen with the patient’s breathing. In patients affected by hemothorax, you will see the liver or the spleen, according to the side you’re probing, the bright line of the diaphragm and on the left side of the screen, there will be a sort of black triangle or black strip, which is fluid (Figs. 4.3, 4.4, 4.5, and 4.6). As you may recall from the abdominal views, fluid is (almost) always black on the screen. That simple. Since these views can be considered an extension of the abdominal examination, you will use the curved array. Now we can explore the chest to detect PTX. In order to obtain a correct chest exam, we need to set our US machine to let us see artifacts (i.e., you have to switch off any artifact reduction algorithm that US machine manufacturers are proud of). You may explore the chest using almost any kind of probe, but it’s advisable to use the linear array, because higher resolution helps to tell the very artifacts we’re looking for. When you will become skilled, you will use phased array or curved probes too.

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Figs. 4.3, 4.4, 4.5, and 4.6 Hemothorax. On the right of the figure, there is the texture of the solid organ (spleen or liver). You may notice the bright, curved line of the diaphragm, and on the left side (above the diaphragm) there is the fluid. Note the collapsed lung appears “solid” with some white spots (trapped air bubbles)

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Figs. 4.3, 4.4, 4.5, and 4.6 (continued)

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Fig. 4.7 Position of the probe on the chest when scanning for PTX

Fig. 4.8 Scheme of a classic US chest view for PTX: two ribs with their shadows and amidst them the pleural line

Key landmarks Rib shadow

Rib shadow

Pleural line

The probe will be applied longitudinally, on the midclavicular line, on the uppermost area of the chest (your patient is in supine position) (Fig. 4.7). You have to recall the anatomy of the chest wall. Think of it in layers: skin and subcutaneous tissue, muscles, ribs, and pleura (Fig. 4.8). When you apply the probe on the chest of the patient, the first image you have to look for is the “bat sign” (Fig. 4.9), an original way to describe normal US anatomy. The bat sign is characterized by two ribs and their shadows and the pleural line. As you can see in Fig. 4.9, with a bit of imagination, you can see the wings of the bat (the ribs with their acoustic shadow) and the back of the bat (the bright pleural line), flying toward you. This particular static sign allows us to know if our ultrasound exam will be conducted properly: in fact if you’re not able to see the bold white line between the rib shadows (pleural line), you cannot tell if there is a PTX. (NB: properly, pleural line defines the visceral pleural interface sliding up and down, so it is obviously not detectable if there is PTX, but to help you in familiarizing with chest US, let’s call pleural line the white line 1 cm below and between the two rib shadows.)

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Fig. 4.9 Two ribs with their shadows and amidst them the pleural line: the so-called bat sign

No bat, no exam!

In trauma patient, we have to pay particular attention to subcutaneous emphysema, since high acoustic impedance of the air in subcutaneous tissue will deflect the ultrasonic beam, preventing us to detect the bat sign and thus to perform the exam. Once we clearly see the pleural line, we can start the exam looking for a dynamic sign called “sliding lung” or “gliding sign.” The “sliding lung” can be described as a rhythmic sparkle of the pleural line, moving synchronously with the breathing cycle of the patient. It’s generated by the comet tail artifacts of the air in the outer alveoli, just beneath the visceral pleura sliding on the parietal pleura (Fig. 4.10). If you can detect the sliding lung, you can be sure there is no PTX. In order to identify the sliding lung properly in difficult environment (i.e., bright lights in ER reflecting on the US machine screen), you can switch on the M-mode (motion mode), and you’ll have a second useful dynamic sign: the seashore sign. M-mode measures the intensity of each single point along the scanning line. If a structure remains still, it will produce horizontal lines (since in M-mode our Y-axis on the screen is depth and X-axis is time). If a structure moves, it will produce a “granular” pattern (Fig. 4.11).

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Fig. 4.10 Close-up of the pleural line. Notice the small vertical comet tail artifacts departing from the bright line

Fig. 4.11 Seashore sign. You may notice the different patterns in M-mode: above the pleural line, the linear pattern, and the granular pattern below it

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Fig. 4.12 Stratosphere sign. No granular pattern can be identified. The very small intermittent “granular” pattern columns are related to the movement transmitted to the lung by the beating heart (“lung pulse”)

As you can see in Fig. 4.11, the chest wall stands still (i.e., makes lines), while from below the pleural line (the bright line), all we have is granular pattern. With a bit of imagination, you can describe this image as waves (lines) crashing on the beach (granular pattern). Seashore sign (M-mode) is a good method for ruling in/ruling out PTX when you are a beginner or you are in doubt, because it makes often the diagnosis simpler and quicker. When our patient is affected by a PTX, no granular pattern could be detected, and the seashore becomes the stratosphere sign (all horizontal lines; Figs. 4.12 and 4.13). Nothing is moving; horizontal lines are everywhere on the screen.

Sliding Lung: Tips and Tricks

• Amplitude of sliding lung increases from lung apex to basis progressively • Dyspnea makes the diagnosis difficult, even in M-mode, because our patient is using even his accessory muscles, making our image shake with every breath

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• Pleural line is interrupted by rib shadows. If you’re in trouble, put the probe on cartilages, next to the sternum: cartilage does not completely block ultrasound! • Sliding lung has to be seen in spontaneous and assisted ventilation. It’s useful to diagnose a wrong endotracheal intubation! • Apnea cancels the sliding lung (but not small vertical artifacts at the pleural line – “comet tails”)

Fig. 4.13 A PTX, in both B- and M-modes

Another important dynamic sign, pathognomonic of PTX, is the “lung point.” It is pathognomonic for PTX. You can imagine the lung point to be the point in which the collapsed lung touches the chest wall during breathing cycle. On your US machine screen, the lung point will appear as an alternation between the presence and absence of sliding lung (Figs. 4.14 and 4.15). Lung point allows you to define the extent of PTX; from medial to lateral, you can assess where the lung point is (parasternal, on midclavicular, on anterior axillary, on midaxillary, etc.), precisely evaluating the entity of PTX and relating it to patient status. Complete PTX has no lung point!

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Fig. 4.14 Lung point

Fig. 4.15 Lung point (M-mode): alternation between stratosphere and seashore signs

Lung point is better observed with the probe along the axis of the intercostal space, eliminating the rib shadows.

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Warning!

• Don’t lose time with US if a tension PTX is suspected (patient is in shock) • Priority is to decompress the thorax • If needed, use the probe for a few seconds: rule out hemothorax, confirm PTX (parasternal), and insert the needle and drainage

Several other static signs were described and cataloged (Lichtenstein) using alphabet letters. From our practical perspective, just three of them are the most significant for clinical approach: 1. A-lines 2. B-lines 3. E-lines A-lines are horizontal reverberation artifacts, repeating themselves below the pleural line at regular intervals, roughly equal to the distance between the skin and the pleural line (Figs. 4.16, 4.17, and 4.18).

Figs. 4.16, 4.17, and 4.18 A-lines. Notice the bright horizontal lines underneath the pleural line, at regular intervals

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Figs. 4.16, 4.17, and 4.18 (continued)

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Their number has no clinical relevance, while their presence does. Be aware: A-lines are not moving; they are normal pattern in both PTX and normal lung! You can find similar artifacts even looking at it in the bowel. B-lines are vertical, laser-like artifacts, departing from the pleural line and descending to the lower edge of the screen, increasing in thickness as they go down (Figs. 4.19 and 4.20). They move synchronously with the sliding lung. They can be as few as one or multiple. Plenty of B-lines (till a so-called white lung) means a wet lung (lung contusion, pulmonary edema, ARDS) (Figs. 4.21). Fine US lung semiology is out of the scope of this book. B-lines are better visualized with convex or phased array probe. The last artifact of interest is called E-line (Fig. 4.22). Generated by the air in the subcutaneous tissue, this particular artifact appears as long or short vertical lines, masking the bat sign. It is very important to identify the bat sign BEFORE starting to classify artifacts for diagnosis, because if you have subcutaneous emphysema, you cannot see the pleural line and thus you cannot tell a PTX.

Figs. 4.19, 4.20, and 4.21 B-lines and the so-called lung rocket. The laser-like vertical lines go down to the edge of the screen

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Figs. 4.19, 4.20, and 4.21 (continued)

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Fig. 4.22 E-lines. They look almost like the B-lines, but no bat sign can be detected. There is subcutaneous emphysema: Lung US not possible

4.3

Clinical Meaning: Diagnosis of Pneumothorax

Let’s get to the core: how can I diagnose a PTX with US? When you suspect a PTX, you should apply the probe on the anterior chest wall and check for the sliding lung. If you can detect it, your patient has no PTX. Move the probe toward the feet, till you see the liver (on the right side) or heart (on the left). Small PTX are located parasternal, over the diaphragm (right), and over the heart (left), not at the apex, as your patient is in supine position. If you cannot tell the sliding lung and you can see the A-lines, you should check for a lung point. If lung point can be seen, that’s your evidence of PTX. With lung point detection, you also have a crude idea of the extension of the PTX. If in different positions over the chest you cannot detect the lung point (and sliding lung neither), you should think of a massive PTX and act accordingly.

Key Points

• • • •

Sliding lung → no PTX Sliding? No comet tails? Yes → apneic patient or wrong intubation Sliding + lung point → PTX No Sliding + no lung point → complete PTX

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Here is a small flow chart (Fig. 4.23): In the very spirit of “think binary,” with this chart in mind, we can exclude or diagnose a PTX (and have a rough idea of its extension as well) in less than 2 min.

Sliding lung? (B-mode or M-mode)

NO

YES

NO PTX

Vertical artifacts?

YES

NO

YES

Lung point?

PTX

NO

Mild

Moderate

Severe

Fig. 4.23 Pneumothorax diagnosis flow chart

Complete PTX

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Remember

• Check for hemothorax at the same moment you scan abdominal RUQ and LUQ with the convex probe • Don’t lose time: missed small hemothorax are not clinically relevant; you are treating a trauma patient! • Detection of PTX is simpler than free fluid in the abdomen • Start with linear probe for PTX if you are not an expert • Don’t move the probe checking for PTX (you are finding for lung sliding!) • Small PTX are caudal, not at the apex

Suggested Reading 1. Blaivas M, Lyon M, Duggal S (2005) A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. Acad Emerg Med 12:844–849 2. Lichtenstein DA, Menu Y (1995) A bedside ultrasound sign ruling out pneumothorax in the critically ill. Lung sliding. Chest 108:1345–1348 3. Lichtenstein D, Meziere G, Biderman P, Gepner A (1999) The comet-tail artifact: an ultrasound sign ruling out pneumothorax. Intensive Care Med 25:383–388 4. Lichtenstein D, Meziere G, Biderman P, Gepner A (2000) The “lung point”: an ultrasound sign specific to pneumothorax. Intensive Care Med 26:1434–1440 5. Soldati G, Testa A, Sher S, Pignataro G, La Sala M, Silveri NG (2008) Occult traumatic pneumothorax: diagnostic accuracy of lung ultrasonography in the emergency department. Chest 133:204–211 6. Zhang M, Liu ZH, Yang JX, Gan JX, Xu SW, You XD, Jiang GY (2006) Rapid detection of pneumothorax by ultrasonography in patients with multiple trauma. Crit Care 10:R112

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Including EFAST in Trauma Algorithms: When? What Now? Diego Mariani and Mauro Zago

5.1

Introduction

You have learned to recognize fluids: liquid effusions (in abdominal or pericardial or pleural cavity) or free air in the thorax. In other words, you know how to quickly detect hemothorax, pneumothorax, pericardial effusion, and free fluid in the abdomen. You also know that the sequential steps for a decision-making process helped by US could be summarized as follows: Is my patient in a life-threatening condition? Should I overcome EFAST? If no, EFAST  where is fluid/air? PHYSIOLOGY + ANATOMY + EFAST ⇓ my decision is ↓ life-saving maneuver or immediate DCS or further work-up

D. Mariani, MD (*) General Surgery Department, AO Ospedale Civile di Legnano, Via Papa Giovanni Paolo II, Legnano, Milano 20025, Italy e-mail: [email protected] M. Zago, MD General Surgery Department, Minimally Invasive Surgery Unit, Policlinico San Pietro, Bergamo, Italy e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_5, © Springer-Verlag Italia 2014

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• Neither detection of injured organs nor a precise diagnosis is required for decision • The key point on which to apply EFAST findings is patient physiology • All lesions not “producing” free fluid will not be in the range of EFAST: if you suspect them, go ahead with your further step

5.2

The Common Role of US Exam in Trauma

The “golden hour” paradigm is not a strictly clock-related concept but means an evidence increasing of morbidity and mortality if care is delayed beyond the first hour after injury. So a quick examination like focused sonography found a kind of a natural place in the primary evaluation of traumatized patient, both in hospital and in prehospital settings. The first aim of EFAST is to assist in assessing the undifferentiated hypotensive status secondary to a blunt trauma. It could be also selectively applied in the evaluation of penetrating torso trauma. For its “focused” nature, EFAST sonography has some limits which must be known. Specificity is high. So, if my EFAST is positive, I could be sure there is an effusion (abdominal, pericardial, or thoracic), and these results must be related with the clinical condition of the patient. Sensitivity depends on my skills, the patient, and time from trauma. So, if my EFAST is negative, it is very important to be very sure about my images and interpret them cautiously in both blunt and penetrating traumas, because the presence of an underlying lesion in abdominal trauma is not always related with free fluid, especially in the early period. Some lesions don’t produce free fluid (retroperitoneal bleeding, intraparenchymal lesions); others sometimes require time to develop effusion (bowel injuries, for instance). When we performed a focused sonography examination in trauma setting, we do a particular sonography with a particular point of view.

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• EFAST applies to thoracic and abdominal trauma • The choice of the sequence of scans is mostly dependent on the patient’s trauma status and mechanism • EFAST should be performed – During the primary survey in physiologically unstable patients – At the end of primary survey in normal and stable patients – During the secondary survey and whenever needed by changes in patient clinical status • EFAST refers to B and C steps of the primary survey

Taking in mind the basic ATLS method of assessing a trauma patient, which is valid for both major and minor traumas, it will be not so difficult to realize and agree what is depicted in the box above.

5.3

Common Algorithms

Simple algorithms including EFAST and its meaning for clinical decision in blunt and penetrating trauma are shown below. Brief comments are given for each one in order to explain some points of the flow chart. Before taking a look at them, please consider that: • There is a great debate in the last few years about the concept of hemodynamic instability. For this reason, in order to do not be confusing, we prefer to talk about “normal” or “not normal” hemodynamics and physiology. Always remember that the first treatment of bleeding is to stop the bleeding and misdiagnosed latent shock should be carefully anticipated (with EFAST too). • For didactical purposes, flow charts are presented for different anatomic areas (thoracic, abdominal). In order for you to merge them, you could imagine to apply them to some complex trauma patients you mananged a few days ago. • These flow charts are not fully comprehensive trauma algorithms. They highlight the place and the decisional role of US. • Finally, local resources can significantly change the clinical path. For that reason, sometimes a list of option is shown.

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Blunt Abdominal Trauma

Fig. 5.1 Proposed algorithm for blunt abdominal trauma

a

b

Here following a Flow chart on Blunt Abdominal Trauma (Fig. 5.1) to which some additional considerations are to be made: 1. *Other sources of shock: hemorrhage elsewhere (thorax, pelvis, bones, retroperitoneum), tension PTX, cardiac tamponade, neurogenic shock, cardiac pump failure. Consider you could rule in/rule out some of them with US in a few seconds! 2. Peritonitis in trauma is a mandatory indication for surgery. Further workup and/or laparoscopy could be used in selected cases 3. The list of possible indications for CT after a negative or slightly positive abdominal EFAST views is based on literature proposals. Having your own protocol is advisable

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Pelvic Trauma

Fig. 5.2 US driven protocol for Pelvic Trauma

This flow chart is for a patient with clinically or more often radiologically documented pelvic fracture at high risk of bleeding (in the vast majority of cases, Tile B/C fractures). US has a pivotal role for orienting the definitive treatment. Comments to the Pelvic Trauma Flow Chart 1. Possible options for treatment are listed; choice depends on skills, resources, training, etc., and is out of the goal of this chapter. 2. Physiology (hemodynamics, coagulation, core temperature, pH, etc.) and pelvis X-ray features (type of fracture relates to the mechanism of injury) are the main criteria for choosing the best treatment. FAST is the best tool for assessing priorities and deciding for the need of full laparotomy, extraperitoneal packing, or external fixation +/− angioembolization. 3. Don’t forget the KISS (keep it simple and stupid): close the pelvic ring immediately before any further diagnostic and therapeutic maneuver, if needed. 4. In up to 18 % of patients with pelvic fracture, free abdominal fluid is urine (bladder rupture): if in doubt and clinical and US findings do not fit with patient status, use again US and perform a diagnostic peritoneal aspiration (DPA). In 20 s, without risks, you solve your problem: immediate or maybe delayed surgery for repairing a ruptured bladder. 5. In stabilized patient, you have time for CT and eventually angioembolization. 6. If patient hemodynamics is normal, algorithm is that of blunt abdominal trauma (see Fig. 5.1).

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Penetrating Abdominal and Thoracoabdominal Trauma

Fig. 5.3 EFAST driven protocol in penetrating thoraco-abdominal injury

a

b

The main recognized role of EFAST in penetrating abdominal trauma is to ruling in/ out intraperitoneal injuries in physiologically normal patients. It has a high positive predictive value. Comments to Penetrating Abdominal Trauma Flow Chart 1. Blood or enteric fluid? A US-guided DPA is sometimes crucial and can change your decision. If the patient is hemodynamically normal, with a few amount of fluid in the abdomen, but you retrieve blood with DPA, you can probably observe this patient. If the patient is hemodynamically normal, with a few amount of fluid in the abdomen, but you retrieve bile/enteric with DPA, go straight to OR (laparoscopy or laparotomy). 2. US can help you in prioritizing the surgical approach (chest first vs. abdomen first) in thoracoabdominal penetrating trauma.

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Penetrating Thoracic Trauma (“Cardiac Box”)

Fig. 5.4 Flow chart for Penetrating Thoracic Injury in the “cardiac box”

Comments to Penetrating Thoracic Trauma Flow Chart 1. Pericardial window is a diagnostic procedure. A reliable US makes it unuseful. 2. Pericardial windows require to be ready for an immediate thoracotomy, if positive. 3. Pericardiocentesis in trauma setting is nowadays only a bridge emergency procedure on the way for OR. If you need this, US is a marvelous tool for guiding the maneuver (not explained in this book).

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The Role of EFAST in a Comprehensive US Trauma Management (ABCDE-US): Facing with Clinical Scenarios Mauro Zago and Diego Mariani

Before reading this chapter, be aware of the objectives:

• An overview of extended applications of US in trauma. • The ABCDE-US concept (clinically integrated US). • Try to manage simulated cases with and without US.

6.1

Beyond EFAST

EFAST protocol remains the cornerstone for quickly answering a lot of key questions arising during the assessment of a trauma patient. Its value in speeding the decisions for definitive treatment is demonstrated (Melniker). But from airway management to the detection of fractures, from venous cannulation to pulmonary contusion assessment, and from monitoring volume replacement to NOM follow-up, US revealed extremely useful in many steps of trauma patient evaluation and treatment. An US probe could be ideally put everywhere on the body for answering focused clinical questions. The awareness about that is at the basis of the so-called ABCDE-US concept (Neri), for which the US probe can help in the decision process in every step of the primary, secondary, and tertiary survey in trauma patient. This does not mean you should mandatorily use US for each A-B-C-D-E step, but you have to know you can M. Zago, MD (*) General Surgery Department, Minimally Invasive Surgery Unit, Policlinico San Pietro, Bergamo, Italy e-mail: [email protected] D. Mariani, MD General Surgery Department, AO Ospedale Civile di Legnano, Via Papa Giovanni Paolo II, Legnano, Milano 20025, Italy M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_6, © Springer-Verlag Italia 2014

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Table 6.1 Questions possibly answered by US in trauma patient Primary survey Assessment and possible problems A Definitive airway control B ptx – hemothorax – lung contusion

C Hemothorax – hemoperitoneum – hemopericardium – cardiac motility – venous and artery cannulation -volume replacement – IVC assessment

D Optical nerve caliper (to be validated) E Long bone fractures

Key questions Is tracheal tube in the right position? Why the pt is dyspnoeic? Should I drain the thorax now? Is there an occult ptx requiring drainage in my intubated patient? Why does he desaturate if there is no ptx or hemothorax? Is there free fluid? How much? Does it justify hemodynamic instability? Where is the major hemorrhage? Is there a PEA? Or cardiac tamponade? Should I resuscitate this pt? Should I take the pt to OR before any other diagnostic test? How about preload? How is IVC? How can obtain a quicker and safer vascular access? Can I confirm intracranial hypertension? Is there a femur fracture under this enlarged thigh? Should this explain hemodynamics?

Secondary survey A B ptx – hemothorax – lung contusion C Hemothorax – hemoperitoneum – hemopericardium – venous and artery cannulation – volume replacement – bile (DPA) – pneumoperitoneum – solid organ injuries (CEUS?)

E Long bone fractures, sternal fractures, rib fractures

Key questions

Is abdominal fluid really blood? Is there a hollow viscus perforation? Is there a solid organ injury? Should I perform abdominal CT even in this low energy trauma? Why the physical exam is worsing after observation? Why does the pt complain pain if x-rays are negatives?

rely on US every time you need it, according to the ATLS protocol, provided you know the focused clinical question you have to solve (your clinical mind!) and how to get the proper image (your skills!). Table 6.1 shows a sample of questions you might answer in a critically ill trauma patient. ABCDE-US is a fully clinically integrated US! The power and usefulness of real-time sonographic information for the critical clinical decision-making process remains largely operator dependent, but several experiences have shown that when appropriate training is provided, results are highly accurate and reliable. Surprisingly, you will realize that some applications for this innovative way to use US are not difficult technical skills (for instance, assessment of tracheal tube positioning needs the same skills needed for PTX evaluation); what is amazing and difficult is to “change” our mind, leaving considered gold standards beside, good as second tools. Coming back to the example above, the quickest way to assess the proper positioning of the endotracheal tube is not by chest x-ray but by US: you check, you move if needed, you check again, and you secure, for only a few seconds. Comprehensive US-helped trauma management is flexible: the recent emphasis on “C-ABCDE” approach (find and stop the bleeding as soon as possible!) can be

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strongly supported by US. EFAST can rule in/out torso free fluid. US can confirm that the patient is “empty” (looking at the heart chambers and heartbeat from the subxiphoid view and using IVC calipers), and if a pelvic fracture is present, FAST can give you criteria to decide a strategy (such as laparotomy if there is significant free fluid, but extraperitoneal packing/external fixation/angioembolization if it is not). Comprehensive US-helped trauma management is flexible: its role can change according to your available resources. So, train yourself daily to be able to profit in emergency situations.

• • • •

Brain leads hands: your brain asks for; your hands + US answer No answers? No skills? Go ahead without US US can help you many times until the patient is discharged (not only FAST!) US is a flexible tool: use whenever you need it

Some specific aspects of US applications in trauma are depicted before going through clinical scenarios.

6.2

Assessment of Free Abdominal Fluid: The Scores

Many experimental and clinical studies explored the minimal amount of fluid detectable with US. From the clinical and practical point of view, this is only relatively relevant. We know there are plenty of lesions without free peritoneal fluid, at least at the beginning. US cannot overcome suspicion index, based on trauma mechanism, physiology, clinical evaluation, and associated lesions. A negative FAST gives us more time to reasoning or observe, but is not enough. On the other side, we know the amount of fluid itself is often not enough to impose a laparotomy. Consider physiology first for decision in a hemodynamically unstable patient, assess with other imaging techniques before NOM. So, is there any sense to estimate the amount of free abdominal fluid (hemoperitoneum)? How can we do that? Is it reliable? Three similar score systems are available; none is largely validated (Tables 6.2, 6.3, and 6.4). Whatever score systems you use, it is really easy to get a score (the simplest are Huang and McKenney). Is there a utility? What is the meaning of the scores? In Huang series, score ≥3 was associated with more than 1,000 ml of blood in 84 % of operated patients; Huang scores excluded. • Ask for blood and frozen plasma. • Go quickly ahead with CT completion for ruling in/out hemoperitoneum. • Alert OR. OK. There is a huge hemoperitoneum with splenic injury OIS 4. Next step is emergency laparotomy. It is good if you are in OR 50 min after arrival. Crash laparotomy, aspiration of 4 l of blood, and splenectomy were performed. Blood is oozing from a lacerated mesentery and from any other rough surface. You ask the anesthesiologist, “how is the pH and core temperature?” pH 7.12; core T 34.2 °C Need to bail out. The following were performed: temporary abdominal closure, ICU rewarming and resuscitation, and transfusion of 7 FFP, 10 RBC, and 1 PLT units. Thirty-six hours later, a planned relaparotomy is performed. You find a segmental small bowel ischemia due to mesenteric laceration. Bowel resection is required, definitive abdominal closure performed. The patient is discharged on day 10. In summary: good choices, Damage Control Surgery correctly applied.

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______________________ BUT imagine having decided to perform EFAST during the primary survey. Look at the relevant US findings: Fig. 6.2 RUQ view

Fig. 6.3 LUQ view

Fig. 6.4 Pelvic view, sagittal

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What do you think? Question 1 RUQ is LUQ is Pelvic view is

• • • • •

NORMAL ____ NORMAL ____ NORMAL ____

ABNORMAL ____ ABNORMAL ____ ABNORMAL ____

Do you change strategy? CT scan again? Or immediately OR? If OR is your choice, you probably agree this could be the story: Laparotomy in 20 min after arrival Aspiration of 1.5 l of blood, splenectomy, and repair of minor laceration of the mesentery No transfusions No ICU Discharge on day 7

6.7.2

Case 2a

This scenario should be managed with a comprehensive US protocol. Answer and check step by step at the end of the chapter.

A 32-year-old woman had been involved in a one-car collision. She was a passenger in the front seat and restrained. Her car rolled over. She was trapped for 15 min. The windshield was smashed. She was conscious, and the vital signs are as follows: BP 120/70 dropped to 90/75, HR 90/min, RR 32, and SaO2 90 % with O2 supplementation. Torso and pelvis seem injured. Five hundred milliliters of crystalloids was infused during transport to ED.

Primary Survey in ED A: Maintained B: Decreased breath sounds on the right lung SaO2: 83 % C: BP 75/50, HR 110/min, clinically unstable pelvic fracture D: GCS 14, confused E: Temp 35.7 °C Infusion of crystalloids, 750 ml

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Question 1 Which critical questions and decisions you need a quick answer for? (Write below with a pencil and then compare with suggestions at the end of the chapter) ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Question 2 Do you think EFAST could help you? YES ____ NO ____ Question 3 If NO, If you have chosen NO, you prefer to follow a surgical path that is not US driven and might miss some opportunities. Please read what would happen with US for your information: may be you become surprised! If YES, list the finding you could rule in/out in a few seconds with US, waiting for pelvis x-ray: (Write below with a pencil, solutions at the end of the chapter) ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ This was the pelvis x-ray of the female patient

Fig. 6.5 Clearly an open book fracture!

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Fig. 6.6 Clearly an open book fracture!

And these are the US relevant findings: (No PTX on both sides)

Fig. 6.7 Right hemithorax view

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Fig. 6.9 RUQ

Fig. 6.10 LUQ

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Fig. 6.11 Pelvic view

a

b

Fig. 6.12 IVC view. (a) Expiration. (b) Inspiration phase

Question 4 Interpret US images: 1. 2. 3. 4. 5. 6.

Right hemithorax Left hemithorax RUQ LUQ Pelvis IVC view (insp.)

NORMAL ____ NORMAL ____ NORMAL ____ NORMAL ____ NORMAL ____ FULL ____

ABNORMAL____ ABNORMAL____ ABNORMAL____ ABNORMAL____ ABNORMAL____ EMPTY____

(Go at the end of the Chapter for solutions, and come back quickly)

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Now, you know that: Your patient is in shock. There is blood in the thorax: YES_____ NO _____ There is blood in the belly: YES_____ NO _____ There is an open book fracture (type B1). You know these kinds of fractures are generally associated with venous and only rarely arterial bleeding. Now, you can decide: • If not yet done, put a sling around the pelvic ring and intrarotate the legs. • Look at hemodynamics evolution. (It should rapidly improve … Yes, it improves! BP 100/65, HR 90/min, GCS 15) • Depending on your resources (your hospital, your team, your trauma system, etc.): – CT scan (first option, if possible) --> excluded other visceral lesions, further decisions for pelvic fracture (angiography if arterial blush or indirect signs of arterial injury, immediate ORIF, external fixation and delayed ORIF) – External fixation and close resuscitation/observation – Immediate transfer to a referral center ________________________________________________________ Different situations could be depicted for a similar case scenario, with identical conditions on the scene and after primary survey in ED. A. B. C. D.

6.7.3

Case 2b

Same patient, same mechanism of trauma, and same clinical findings. You perform now the US on this unlucky female with the same pelvic fracture shown on Fig. 6.5. Look at the US findings (No PTX on both sides):

Fig. 6.13 Right hemithorax view

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Fig. 6.14 Left hemithorax view

Fig. 6.15 RUQ

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Fig. 6.16 LUQ

Fig. 6.17 Pelvic view

a

b

Fig. 6.18 IVC view. (a) Expiration. (b) Inspiration phase

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Question 5 Interpret US images: 1. 2. 3. 4. 5. 6.

Right hemithorax Left hemithorax RUQ LUQ Pelvis IVC view (insp.)

NORMAL ____ NORMAL ____ NORMAL ____ NORMAL ____ NORMAL ____ FULL ____

ABNORMAL ____ ABNORMAL ____ ABNORMAL ____ ABNORMAL ____ ABNORMAL ____ EMPTY ____

(Solutions at the end of the Chapter) Question 6 Now, you know that: A. Your patient is in shock. B. There is blood in the thorax: YES_____ NO _____ C. There is blood in the belly: YES_____ NO _____ D. Grossly, Huang score is __; McKenney score is __; Sirlin score is __. E. The probability of surgical intraperitoneal bleeding is HIGH ____ LOW ____ F. There is an open book fracture (type B1). You know these kinds of fractures are generally associated with venous and only rarely arterial bleeding. (Look at right answer before turning the page.)

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Now, you can decide. I don’t think you take the same decisions as in the previous situation … • If not yet done, put a sling around the pelvic ring and intrarotate the legs. • CT? No, please! • Massive transfusion protocol activation (if not yet done). • Damage Control strategy and resuscitation, wherever you are and whatever are the skills of your team: – Straight to OR. – Stop the bleeding (damage control surgery). – Possible pelvic packing. – External fixation or pelvic binder. ICU for stabilization.

So :

• • • • •

Different clinical decisions In similar settings Thanks to US findings Obtained in a few seconds REMEMBER: ABCDE-US helps you to quickly “see and assess” the anatomy and physiology for decision making

Here is an already printed algorithm, with a slight modification

Is my patient in a life-threatening condition? Should I overcome EFAST? If no, EFAST ® where is fluid? ABCDE-US ® other quick info on anatomy&physiology?

PHYSIOLOGY + ANATOMY + ABCDE-US Ó my decision is ¯ life-saving maneuver

or

immediate DCS

or

further work-up

Summary • US can help you in assessing faster BOTH anatomy AND physiology • A comprehensive US-driven trauma management allows you to explore the potential of US probe in your hands

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Clinical Scenario Answers Case 1 Question 1 RUQ is LUQ is Pelvic view is

NORMAL ____ NORMAL ____ NORMAL ____

ABNORMAL __X__ ABNORMAL __X__ ABNORMAL __X__

Case 2 Question 1 Which critical questions and decisions you need a quick answer for? Below are some possible answers: • Right PTX or hemothorax? • Is there blood in the belly? • Which is the priority for managing shock? Thorax, abdomen, or pelvis? • Straight to OR or time for further investigations? (It depends on resources too.) • If to OR, which problem is to fix first? • Is she pregnant? Question 2 Do you think EFAST could help you? • YES, of course! Question 3 List the finding you could rule in/out with US: • Hemoperitoneum (yes/no) • Assessment of the amount of hemoperitoneum (Is it a shock from pelvis fracture only and/or intra-abdominal injury?) • Hemothorax (yes/no) • Pneumothorax (yes/no) • IVC diameter: is my patient completely “empty”? Question 4 Interpret US images: • All US EFAST views are normal. • Your patient is empty. • No pregnancy. No fluid detectable everywhere. Your patient is probably bleeding only from the pelvic fracture! Question 5 Interpret US images: 1. 2. 3. 4. 5. 6.

Right hemithorax Left hemithorax RUQ LUQ Pelvis IVC view (insp.)

NORMAL NORMAL ABNORMAL_free fluid ++__ ABNORMAL_free fluid ++__ ABNORMAL_free fluid ++, floating loops EMPTY

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Question 6 Now, you know that: A. Your patient is in shock. B. There is NO blood in the thorax. C. There is blood in the belly. D. Grossly, Huang score is >3 (at least 5: Morison 2 + Douglas 2 + Perisplenic 1); McKenney score is >3 (8 [cm in Douglas pouch, at least] + Morison 1 + Perisplenic 1); Sirlin score is at least 3 (Douglas 1, Morison 1, Perisplenic 1). E. The probability of surgical intraperitoneal bleeding is very HIGH.

Suggested Reading 1. Mayse ML (2005) Real-time ultrasonography. Should this be available to every critical care physician? Crit Care Med 33:1231–1238 2. Melniker LA (2006) Randomized controlled clinical trial of p-o-c limited US for trauma in the ED: the first SOAP trial. Ann Emerg Med 48:227–235 3. Neri L, Storti E, Lichtenstein D (2007) Toward an ultrasound curriculum for critical care medicine. Crit Care Med 35(Suppl):S290–S304 4. Zago M (2009) Time for a comprehensive US-enhanced trauma management. Eur J Trauma Emerg Surgery 35:339-40

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Prehospital Ultrasound in Trauma: Role and Tips Miriam Ruesseler

7.1

Introduction

Abdominal trauma in combination with pelvic injuries is a major cause of death in patients with multiple injuries in the first 24 h after trauma. In blunt abdominal trauma (BAT), determining which patients should be triaged to laparotomy is important, even more, when these patients are unstable. A rapid, accurate triage and initiation of resuscitation and specific therapy are crucial as delayed treatment is associated with increased morbidity and mortality. The ultrasound examination (FAST) is the gold standard as early screening method in the emergency department (ED) and provides a quick, standardized overview of the intraperitoneal cavity searching for the typical sites of free fluid accumulation as already described in detail in previous chapters. Meanwhile, it is part of the Advanced Trauma Life Support® algorithm. The presence of free abdominal fluid in the ED in combination with hemodynamically unstable patients indicates the necessity of urgent laparotomy without any further diagnostics [1–3]. At the trauma scene however, clinical parameters and physical examination are the only prehospital measures to detect intra-abdominal bleeding in spite of its low accuracy and reliability. In patients with undiagnosed intra-abdominal bleeding, crucial time may be lost. The determination of a source of hemorrhage at the trauma scene might expedite transport and disposition and may result in more timely and effective definite therapy. Through a joint civilian-military initiative, the first portable handheld ultrasound devices were developed suitable for the battlefield or a mass casualty situation. The modern handheld devices are small and lightweight with adequate battery life and have increasing technical features with relative simplicity to use and an excellent quality of image scans. These handheld devices add one more dimension to FAST M. Ruesseler, MD Department of Trauma Surgery, University Hospital of the Goethe-University, Theodor-Stern-Kai 7, Frankfurt 60590, Germany e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_7, © Springer-Verlag Italia 2014

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as they make prehospital FAST (p-FAST) a possibility to detect life-threatening injuries within the “golden hour” and appropriately triage the patients as demonstrated in several studies.

7.2

Feasibility of p-FAST

Several studies confirmed the feasibility of p-FAST in prehospital trauma care [4– 9]. These studies were able to demonstrate that p-FAST could be performed in both ground-based and air rescue with a sensitivity, specificity, and accuracy comparable to FAST under inhospital conditions (Table 7.1). In 95 % of the investigated patients (219/239) by Walcher et al. [9], the time frame was sufficient to integrate and complete p-FAST into prehospital trauma care algorithm. The investigation time of p-FAST is comparable to inhospital times in the ED (p-FAST with negative findings: 2.4 ± 0.8 min [9]; FAST with negative findings: 2.3 to 2.6 + 0.25 to 1.2 min [1, 3]). p-FAST can lead to relevant changes in prehospital trauma therapy and management with the aim to shorten the time to surgical therapy (Table 7.2). The patients receive p-FAST on average 35 ± 13 min prior to inhospital FAST or CT scan [9]. Early diagnosis is precious as it can contribute to accelerate and optimize patient care and orientation. Detection of hemoperitoneum at the trauma scene means that the receiving hospital can be notified in advance and the inhospital trauma team can modify their preparations by expanding their team to include a surgeon and prepare theater for urgent laparotomy for hemorrhage control. Based on the p-FAST results, the admitting trauma center might be changed toward the closest appropriate hospital, especially in rural settings, where mean response times and mean transport times can be much longer. Table 7.1 Sensitivity, specificity, and accuracy of ultrasound in blunt abdominal trauma Diagnostic reference First author and Year Modality n Sensitivity Specificity Accuracy standard reference no. 400 81 97 94 DPL, CT Boulanger [1] 1996 FAST Brown [10] 2001 FAST 2,693 84 96 96 DPL, CT, laparotomy, autopsy 96.9 91.6 CT, laparotomy Kirkpatrick [6] 2005 HHFAST 313 68.6 Walcher [9] 2006 p-FAST 202 93 99 99 CT, laparotomy 2006 PHASE 38 90 96 FAST, CT Busch [11] Modified from Ruesseler et al. [12] FAST focused abdominal sonography in trauma, HHFAST handheld FAST, p-FAST prehospital FAST, CT computed tomography, DPL diagnostic peritoneal lavage, PHASE prehospital application of sonography in emergencies

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Prehospital Ultrasound in Trauma: Role and Tips

Table 7.2 Consequences of p-FAST results [9]

7.3

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Modification in therapy (21 %) and management on scene (30 %) Changes in selection of trauma center (22 %) Information transfer about prehospital findings to trauma team (52 %) Changes in trauma team preparation and management (92 %) Ultrasound on scene 35 min prior to FAST in the emergency department

Training

US is the first and foremost an operator-dependant examination. Thus, experience plays an important role, and sensitivity drops with little experience. A standardized training with both theoretical and hands-on modules is mandatory to gain the required skills to conduct FAST or p-FAST sufficiently. This training should include subjects with positive findings. Emergency physicians/paramedics treating patients at the scene of an accident face several challenges such as time pressure. This has important implications for the training program. Thus, the training program should include real-time simulation training and different patient positions (e.g., ventral position), where the learner has to find the appropriate time frame to integrate p-FAST into the prehospital trauma care algorithm, adopt the transducers’ position, and furthermore face the time pressure. After a 1-day course with hands-on training as described above, p-FAST can be performed by both paramedics and physicians who were not familiar with the technique before attending the course with a high sensitivity, specificity, and accuracy [13]. However, to maintain this skill at the required competence level, regular practice is necessary.

7.4

Tips and Pitfalls

p-FAST should be performed on all traumatized patients with suspected BAT. As intra-abdominal bleeding is a dynamic situation, p-FAST should be repeated every 15 min during the prehospital period as well as in the emergency department if suspicious physical findings with negative or slight positive initial p-FAST result occur as hemorrhage may not yet have been apparent [2]. Thus, p-FAST can be used to monitor the patient. p-FAST can be performed within the first several minutes, while other team members are carrying out simultaneous diagnostic and therapeutic maneuvers. However, the appropriate time frame has to be considered, as p-FAST should not delay the trauma algorithm, constrain other necessary procedures, or even delay the prehospital transport to the hospital and thus the definitive treatment. Reasons for an incomplete p-FAST can be bright sunlight (technical failure), gross obesity, thoracic skin emphysema due to lack of penetration of sonographic

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waves or reverberation artifacts. Duration of examination has to be kept short; thus, if the examination cannot be performed properly, it should be stopped and repeated under optimized conditions (e.g. different patient position). p-FAST should be used as screening method to identify patients at risk. It is not indicated for a definitive diagnosis as the only question that can be answered with high accuracy is the presence or absence of free fluid. Thus, no time should be wasted on trying to identify organ lesions, but the patient should be moved to CT or operating room as quickly as possible. p-FAST must not be performed if its result would not have any influence on further prehospital therapy, management, or choice of hospital.

Tips and Tricks

US is a highly user-dependant examination; thus, an adequate training and regular practice are obligatory

Tips and Tricks

FAST and p-FAST training should include mainly hands-on training, subjects with positive findings, real-time scenario training, and different subject positions

Tips and Tricks

Repeat p-FAST every 15 min to monitor the patient

Tips and Tricks

Perform p-FAST while other team members simultaneously perform procedures of the trauma algorithm

Pitfalls

Time is wasted on trying to identify organ lesions → p-FAST should only identify the presence or absence of free fluid

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Remember

p-FAST can significantly increase diagnostic performance and diagnostic accuracy. However, it should never delay the prehospital trauma algorithm nor patients transport to definitive therapy. US is highly user-dependant; thus, training and regular practice are obligatory.

References 1. Boulanger BR, Mclellan BA, Brenneman FD et al (1996) Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma. J Trauma 40:867–874 2. Rozycki GS, Ballard RB, Feliciano DV et al (1998) Surgeon-performed ultrasound for the assessment of truncal injuries: lessons learned from 1540 patients. Ann Surg 228:557–567 3. Wherrett LJ, Boulanger BR, Mclellan BA et al (1996) Hypotension after blunt abdominal trauma: the role of emergent abdominal sonography in surgical triage. J Trauma 41:815–820 4. Brooks AJ, Price V, Simms M (2005) FAST on operational military deployment. Emerg Med J 22:263–265 5. Heegaard W, Plummer D, Dries D et al (2004) Ultrasound for the air medical clinician. Air Med J 23:20–23 6. Kirkpatrick AW, Sirois M, Laupland KB et al (2005) Prospective evaluation of hand-held focused abdominal sonography for trauma (FAST) in blunt abdominal trauma. Can J Surg 48:453–460 7. Lapostolle F, Petrovic T, Lenoir G et al (2006) Usefulness of hand-held ultrasound devices in out-of-hospital diagnosis performed by emergency physicians. Am J Emerg Med 24:237–242 8. Walcher F, Kortum S, Kirschning T et al (2002) Optimized management of polytraumatized patients by prehospital ultrasound. Unfallchirurg 105:986–994 9. Walcher F, Weinlich M, Conrad G et al (2006) Prehospital ultrasound imaging improves management of abdominal trauma. Br J Surg 93:238–242 10. Brown MA, Casola G, Sirlin CB et al (2001) Blunt abdominal trauma: screening us in 2,693 patients. Radiology 218:352–358 11. Busch M (2006) Portable ultrasound in pre-hospital emergencies: a feasibility study. Acta Anaesthesiol Scand 50:754–758 12. Ruesseler M, Kirschning T, Breitkreutz R et al (2009) Prehospital and emergency department ultrasound in blunt abdominal trauma. Eur J Trauma Emerg Surg 35:341–346 13. Walcher F, Kirschning T, Muller MP et al (2010) Accuracy of prehospital focused abdominal sonography for trauma after a 1-day hands-on training course. Emerg Med J 27:345–349

8

CEUS: What Is It? Massimo Valentino, Libero Barozzi, and Cristina Rossi

8.1

Introduction

Contrast-enhanced ultrasound (CEUS) is a new tool for investigating blunt abdominal trauma. Ultrasound contrast agents (UCAs) are exogenous nontoxic substances smaller than red blood cells. In combination with nonlinear imaging methods, they offer the possibility of detecting abnormal parenchymal tissue, accurately recognizing or excluding abdominal solid organ injuries and assessing their size and complications. The technique is capable of showing the extent of the lesions to the capsule and the presence of active bleeding, overcoming the limits of baseline sonography in studying traumatic parenchymal injuries.

8.2

Scanning Technique

8.2.1

How to Scan

UCAs are microbubbles with a diameter from 2 to 6 μm composed of a shell of biocompatible materials, including proteins, lipids, or biopolymers. These agents

M. Valentino (*) Department of Diagnostic Imaging—Radiology Unit, Hospital of Tolmezzo, Via Morgagni 18, Tolmezzo 33028, Italy e-mail: [email protected] L. Barozzi Department of Diagnostic Imaging—Radiology Unit, Maggiore Hospital, Largo Bartolo Nigrisoli, 2, Bologna 40100, Italy e-mail: [email protected] C. Rossi Department of Diagnostic Imaging—Emergency Radiology Unit, University Hospital of Parma, Via Gramsci 14, Parma 43100, Italy e-mail: [email protected] M. Zago (ed.), Essential US for Trauma: E-FAST, Ultrasound for Acute Care Surgeons, DOI 10.1007/978-88-470-5274-1_8, © Springer-Verlag Italia 2014

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are blood pool agents that remain in the intravascular compartment and do not leak into the organ tissue. UCAs are injected IV as a bolus, increasing the signal of the vascularized parenchyma: therefore, in the case of trauma, the areas of laceration appear as defects of perfusion (“black”). CEUS requires contrast-specific software, nowadays available in many portable machines, with the suppression of the static signal of the tissues and highlighting the signal from microbubbles circulating in the bloodstream. The dose of UCA depends on the technical equipment, ranging from 1.2 to 2.4 mL per dose. After IV injection, the microbubbles persist in the bloodstream for 8–10 min and can cross the pulmonary and systemic capillary circulation without trapping. Their long life allows the sonographer to investigate all the abdominal organs in real time. UCAs differ from computed tomography contrast media because they lack interstitial spread, consequently functioning as perfect traces of organ vascularization. They are well tolerated, and serious reactions are rarely reported. Nevertheless, adverse reaction toward UCA constituents must always be considered. Due to the absence of renal excretion, UCAs can be safely employed also in patients with renal failure. For trauma protocol, UCA is administered in two doses for visualization of the right and the left upper quadrant organs, separately. This procedure is needed to study the single organs during all the vascular phases (early and late phases). The study is interpreted simultaneously during the investigation, and the record of the investigation as a video clip allows reviewing for minor lesions, while the acquisition of static images is useful for measuring the lesions. Trauma study begins with FAST protocol, and CEUS follows immediately afterward. During FAST, the optimal patient positions and the accessibility of the organs are assessed for planning CEUS.

8.2.2

Normal Anatomy (Fig. 8.1a–d)

In CEUS, the normal parenchyma appears homogeneously hyperechoic with the vessels having the maximum of echogenicity. The enhancement starts 10–15 s after the UCA injection, the time of delay depending on the specific vascular physiology of the investigated organ. The kidneys show rapid, intense, and transient enhancement due to the absence of glomerular filtration after IV UCA injection. The arterial phase of CEUS starts 10–15 s after intravenous injection and lasts up to about 40 s, when the venous phase becomes prevalent. The venous and late phase lasts from 3 to 6 min. In the arterial phase, the cortex shows the most intense enhancement, whereas in the late phase the whole kidney appears homogeneously perfused. In the liver, UCAs are firstly visualized in the hepatic artery, followed by those in the portal vein. Hence, the CEUS process is always divided into the arterial phase (120 s). In the portal phase, the liver appears homogeneously perfused, with slightly hyperechoic vessels and anechoic gallbladder. The delayed phase is particularly useful for characterization of focal liver lesions since almost all malignant lesions are hypoechoic in this phase. Also traumatic lesions are well visible in the portal and delayed phase.

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Fig. 8.1 (a) CEUS of normal kidney. In the arterial phase, the cortex shows the most intense enhancement. Note the absence of enhancement in the renal pelvis. (b) CEUS of normal liver in the venous phase. In this phase, the liver appears homogeneously perfused, with the vessels and border clearly defined. (c) CEUS of normal spleen in venous phase. In this phase, the parenchyma appears homogeneous with a persistent enhancement for up to 5–7 min. (d) CEUS of normal pancreas. In the venous phase, pancreas has a darkened appearance (arrows) in contrast to the adjacent liver, but the vessels (asterisk) allow to identify it

Splenic parenchyma starts about 12–15 s after UCA injection. In this phase, we can observe an inhomogeneous enhancement of the spleen, resembling the wellknown zebra-striped pattern seen on dynamic CT. The phase can give the false impression of a scattered spleen, confusing the sonographer: we suggest studying first the left kidney and then moving to the spleen in the venous phase. Approximately 50 s after the injection, the venous phase starts, and the splenic parenchyma becomes homogeneous, showing dense persistent enhancement for up to 5–7 min. In this phase, the injured parenchyma is well detectable as a hypoenhanced area. In the pancreas, uptake of contrast medium during CEUS is very rapid; at approximately 25–40 s, it produces a transient, bright homogeneous enhancement that is due to the high vascularization of the organ. Accumulation in the capillaries is negligible; thus, the washout also occurs rapidly after the arterial phase, giving the pancreas a darkened appearance in contrast to the adjacent liver after 2 min. Consequently, CEUS may be difficult at delineating masses, but it allows an excellent delineation of traumatic lesions.

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Tip and Tricks

• A double injection of UCA is needed for studying all the organs in all the phases • In the arterial phase, attention must be focused on the vessels in order to highlight vascular injuries and UCA extravasation! • UCAs are not eliminated from the kidney and cannot visualize lesions of the pelvis and ureter

8.2.3

Traumatic Lesions (What We Have to Search for)

Liver Liver injuries include contusion (subtle and inhomogeneous area without vessel displacement), laceration (clear band-like lesion, linear or branched), and parenchymal or subcapsular hematoma (fluid collection of variable attenuation and echogenicity within liver parenchyma or below the liver capsule). On CEUS, liver lesions appear as markedly hypoechoic lines or bands and are more evident than on baseline sonographic scans, also showing sharper borders (Fig. 8.2). Injury conspicuity increases progressively while passing from arterial phase scans (20–50 s from injection) to portal-sinusoidal scans (50–240 s), owing to a progressive increase in parenchymal echogenicity. On early-phase images, subtle hyperechogenicity (hypervascularity) can sometimes be noted around the injury, suggesting perilesional hyperemia. In lacerative-contusive areas, CEUS allows optimal depiction of defined lacerations, but in comparison with CT, CEUS less effectively depicts the subtle contusive inhomogeneity. In a series of 87 patients, CEUS was more sensitive than unenhanced sonography in directly showing hepatic lesions (87 % vs. 65 %, 100 % specificity) and correlated better with CT for injury size and capsule involvement. Hepatic lesions lack or have very little enhancement, appearing as hypoechoic areas at CEUS. Although they may be visible in all three vascular phases, injuries appear more evident during the venous phase. In the later phase, the images deteriorate very quickly, and the abnormalities become indistinguishable. The venous phase is thus undoubtedly the most efficient for liver injury detection and has been called “the homogeneous phase.” Some injuries, mainly in the liver, may appear quite large on CECT and smaller on CEUS, as reported by McGahan and colleagues. Although surgical correlation is lacking due to the conservative treatment, it is plausible that the hypoechoic area seen with CEUS is related to the parenchymal laceration and the larger area seen with CECT is the sum of the edema and the laceration. If this hypothesis is correct, this is not a pitfall but an added value of CEUS, capable of distinguishing the true lesion (laceration) from the surrounding edema. Minor lesions not seen with CEUS may be areas of edema visible only with CECT but without clinical implication. In liver injuries, CEUS can have some drawbacks. Because of the use of lowemission-frequency harmonics, there is loss in spatial resolution and overall image

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Fig. 8.2 A 19-year-old male admitted to hospital after a motor vehicle accident. (a) Sagittal oblique sonogram shows a large nonhomogeneous hyperechoic area in the right lobe of the liver (arrows). (b) Color Doppler US shows the absence of vascularization. (c) CEUS scan in the same position illustrates a large parenchymal laceration (arrows). The hepatic vessels (asterisks) are in the area of the lesion, but there is no blushing. (d) MDCT confirms the lesion (arrowheads) and the absence of bleeding

quality. The poor signal arising from the most deeply located lesions may give them partially or completely unrecognized, resulting in a false-negative study. Moreover, hepatic steatosis or fibrosis increases attenuation of the US beam reducing CEUS capability and newly resulting in a false-negative study when exploring deep liver portions. Subcapsular or intraparenchymal hematoma appears as a hypoechoic area surrounding or central to the organ, respectively (Fig. 8.3). Active hemorrhage is identifiable during the first phase as an extravasation of microbubbles into the hematoma.

Spleen The spleen enhances very brightly, and UCAs accumulate in the parenchyma, allowing lengthy examination. The superficial position and the small volume permit optimal study. Splenic injuries show a decreased or absent enhancement and are clearly seen as opacification defects, better evident during the late phase of enhancement. A contusion appears as ill-defined, slightly hypoechoic areas, whereas a laceration

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Fig. 8.3 A 62-year-old man admitted to hospital after a motor vehicle crash. (a) CEUS of the liver reveals a fracture in the right lobe (arrow) with a large subcapsular hematoma (calipers). (b) MDCT confirms the lesions (arrowhead and asterisk) Fig. 8.4 Laceration of the lower pole of the spleen. CEUS shows a clearly hypoechoic linear band, perpendicular to the spleen surface (arrows)

is seen as a clearly hypoechoic band, linear or branched, that is usually perpendicular to the spleen surface (Fig. 8.4). Contrast extravasation, indicating active bleeding, is frequently seen in spleen fracture. On CEUS, it is detected as an early-phase hyperechoic pool or jet within the splenic parenchyma or perisplenic hematomas (Fig. 8.5). Differential diagnosis includes calcifications (already visible on baseline images), normal vessels (different appearance and disposition), pseudoaneurysms (limited practical value of differentiation), and uninjured parenchymal areas within large lesions caused by contusions and lacerations (there is a different appearance with lower echogenicity). Decreased splenic parenchymal enhancement (partial or total) is a finding of traumatic infarction in vascular pedicle avulsion. According to our previous report, the sensitivity of CEUS in detection of splenic injuries approaches 100%.

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Fig. 8.5 A 21-year-old male admitted to hospital after a motor vehicle trauma. (a) CEUS scan shows a linear laceration in the lower pole of the spleen (arrow). (b) In the late phase, a focal extravasation of UCA demonstrated an active bleeding (arrow). (c) MDCT confirmed the lesion (arrowhead)

The technique allows the exact evaluation of the number and the extension of the lesions. Complex traumatic lesions can be easily recognized. One disturbing factor that is not correlated to the vascular phases of the spleen is a common, quite rapid decrease of the enhancement in the parenchymal splenic veins. About 2–3 min following the injection, the veins become anechoic. This is probably due to the effective filtration of microbubbles from the circulation on the part of the spleen. At first, this phenomenon is somewhat confusing, as the veins can be mistaken for lacerations, but with awareness of the problem, it can be resolved. If in doubt, a reinjection of a small amount of UCA is an efficient solution.

Kidney Renal injuries present as defects of vascularization in a well-perfused parenchyma. Contusions appear as focal alterations of enhancement; interruption of the renal profile is consistent with a laceration (Fig. 8.6). Renal artery tear or thrombosis presents with the absence of parenchymal perfusion. Focal UCA extravasation suggests active hemorrhage.

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Fig. 8.6 (a) CEUS shows a laceration of the left kidney with interruption of the posterior profile (arrows). (b) MDCT confirms the lesion (arrowheads) (multiplanar sagittal reconstruction)

The homogeneous phase is still the most effective phase for the detection of traumatic injuries. Until today, little specific attention has been paid to the role of emergency sonography in evaluating acute renal trauma. In our experience with traumatic lesions, at CEUS a subcapsular hematoma appears as an inhomogeneous collection surrounding the kidney while a laceration is a clear hypoechoic band, possibly associated with a subcapsular hematoma. It is beneficial to use a small dose of UCA for visualizing the traumatic lesions of the kidney, since too much contrast may cause a glare that covers very thin lacerations. If the phenomenon occurs, it can be corrected by performing a new examination using a low dosage immediately after the bubble destruction. Although injection of UCAs improves the sensitivity of US for identification of renal injuries, the role of this technique in clinical practice is debatable. Injury to the renal collecting system may be overlooked at CEUS because of a lack of microbubbles in urinary excretion. Small renal injuries may be unidentified, especially when perirenal hematoma is small or absent. Pitfalls

• Splenic arterial phase can mimic a scattered spleen. Lesions are visualized in a late phase • Peri-traumatic lesions (extracapsular hematomas) are not visible on CEUS as on CT, because parenchyma remains well vascularized • Contrast extravasation at CEUS imaging is detected immediately after vessel opacification, spreading to the hemorrhage site, and it appears as a round/oval spot of variable sizes or as a fountain-like or serpentine-like hyperechoic jet • Pseudoaneurysm has an appearance very similar to contrast extravasation but is a round or oval mass continuous with the vessel; both occurrences, active bleeding and posttraumatic pseudoaneurysm, require a surgical decision (surgery or embolization)

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Nonoperative Management

Nonoperative management is today the preferred treatment for the solid organ injuries of grades 1–3 according to AAST grading. All nonsurgical patients are usually staged by abdominal CT scanning and are closely monitored in an intensive care unit setting. Although delayed bleeding seems extremely rare, delayed rupture of the spleen remains a major concept; therefore, patients undergo repeated imaging procedures before discharge. Currently, CT plays an important role in the followup, improving the success rate of nonsurgical management. CEUS is ideally suited for the follow-up of abdominal solid organ lesions managed conservatively, especially in young patients, because it reduces the number of CT scans. CEUS can be proposed for serial imaging of conservatively treated solid organ injuries. It can be performed at the bedside safely and without radiation exposure until the lesions are completely healed.

Remember

• The use of contrast agents in ultrasound significantly improves detection of solid organ injury and is an area still under investigation • While contrast-enhanced ultrasound may evaluate solid organ injuries, bowel and mesenteric injuries remain best assessed by CT scan • US is less panoramic than CT, and CEUS cannot replace CT in the initial assessment of trauma • CEUS has the potential to replace CT in follow-up when nonoperative treatment is realized, in an effort to minimize diagnostic radiation, especially in younger patients

Suggested Reading 1. Bertolotto M, Catalano O (2009) Contrast-enhanced ultrasound: past, present, and future. Ultrasound Clin 4:339–367 2. Catalano O, Lobianco R, Raso MM, Siani A (2005) Blunt hepatic trauma: evaluation with contrast-enhanced sonography: sonographic findings and clinical application. J Ultrasound Med 24:299–310 3. Catalano O, Sandomenico F, Raso MM, Siani A (2005) Real-time, contrast enhanced sonography: a new tool for detecting active bleeding. J Trauma 59:933–939 4. McGahan JP, Horton S, Gerscovich EO et al (2006) Appearance of solid organ injury with contrast-enhanced sonography in blunt abdominal trauma: preliminary experience. AJR Am J Roentgenol 187:658–666 5. Piscaglia F, Bolondi L (2006) The safety of SonoVue® in abdominal applications: retrospective analysis of 23188 investigations. Ultrasound Med Biol 32(9):1369–1375 6. Thorelius L (2007) Emergency real-time contrast-enhanced ultrasonography for detection of solid organ injuries. Eur Radiol 17(Suppl 6):F107–F112 7. Valentino M, Serra C, Pavlica P, Barozzi L (2007) Contrast-enhanced ultrasound for blunt abdominal trauma. Semin Ultrasound CT MR 28:130–140

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8. Valentino M, Serra C, Pavlica P et al (2008) Blunt abdominal trauma: diagnostic performance of contrast-enhanced US in children-initial experience. Radiology 246:903–909 9. Valentino M, Serra C, Zironi G et al (2006) Blunt abdominal trauma: emergency contrastenhanced sonography for detection of solid organ injuries. AJR Am J Roentgenol 186: 1361–1367 10. Xu HX (2009) Contrast-enhanced ultrasound: the evolving applications. World J Radiol 1(1):15–24

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