Physical examination of the abdomen has been the

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1 Clinical Articles The use of ultrasound in blunt trauma Author: Thomas T. Levins, RN, CCRN, CEN, CFRN, Yardley, Pa Physical examination of the abdomen has been the mainstay of assessment for the presence of potential intra-abdominal pathology and injury. Are bowel sounds present or absent? Is the abdomen distended, flat, soft, rigid or tender? Is the patient experiencing pain? If so, what type and where? Does the patient have rebound tenderness? Does the patient have associated nausea, vomiting, and diarrhea? In the appropriate patient who is awake and cooperative, this constellation of signs and symptoms is widely thought to be only 50% specific and sensitive for intra-abdominal injury. Medical history or ancillary laboratory tests and radiographs may shed some light on a potential diagnosis. However, even in the best of cases, initial ED evaluation, laboratory tests, radiographs, and surgical consultation may take hours hours the trauma patient with multiple injuries does not have. In the toxic, confused, or paralyzed patient, or in patients with closed head injury and spinal cord injury, the physical assessment of the abdomen may be of little value. Limitations of diagnostic peritoneal lavage Diagnostic peritoneal lavage (DPL), which was introduced by Root 1 in 1965, has proved to have excellent sensitivity and a low false-negative rate. In DPL, a catheter is placed within the peritoneal cavity by one of 3 techniques: closed, semi-closed, or open. After catheter placement within the peritoneal cavity, a syringe is used to aspirate any free fluid contained within the peritoneal cavity. Return of more than 10 ml of blood or obvious gastrointestinal contents is indicative of a positive tap. If no fluid is aspirated, 20 ml/kg up to 1 L of warmed lactated Ringers fluid is infused and allowed to drain by gravity. The fluid return is then sent for laboratory analysis of red blood cells (RBC), white blood cells (WBC), and amylase. An RBC count greater than 100,000 RBC/mm 3, a WBC greater than 500 WBC/mm 3, or an amylase level greater than 200 IU all indicate a positive DPL and intra-abdominal injury. However, DPL is an invasive procedure with a complication rate of approximately 1%. 2,3 The most Thomas T. Levins, Philadelphia Chapter, is a Flight Nurse, PENNSTAR Flight, University of Pennsylvania Medical Center, Philadelphia, Pa. J Emerg Nurs 2000;26:15-9. Copyright 2000 by the Emergency Nurses Association /2000 $ /1/ frequent complications encountered are perforation of the intestines or bladder and laceration of the iliac or mesenteric vessels. 2,3 Furthermore, DPL is oversensitive and lacks organ specificity, possibly leading to an unecessary laparotomy. 4 In addition, it does not assess the retroperitoneum and is time consuming, taking a few minutes to perform even for the most experienced practitioner. Numerous studies have shown that the FAST technique has a sensitivity of 93%, a specificity of 98%, and an accuracy of 97% for identifying intra-abdominal hemorrhage. Limitations of computed tomography scans In 1982, Federle et al 5 examined the use of computerized axial tomography (CT) scans, and their findings led to a rapid growth in the use of CT scans for evaluation of blunt abdominal trauma. CT scans have the advantage of being noninvasive; in addition, they are organ specific and allow quantification of the amount of free fluid in the abdominal cavity. CT scans also allow the grading of specific solid organ injury and assess the retroperitoneum. 6,7 Despite these advantages, however, CT scanning has some significant drawbacks. Appropriate utilization of CT scans requires a hemodynamically stable patient, whereas many trauma patients are not hemodynamically stable. It also requires patient transport to the radiology department and prohibits the performance of concurrent procedures while the CT scan is in progress. CT scans of the abdomen require the administration of intravenous contrast, which may precipitate an allergic reaction or kidney failure in sensitive persons. CT imaging fails to detect hollow viscus injury in approximately 7% of patients with blunt abdominal trauma 8 and requires 24- hour CT technician availability. These disadvantages February

2 JOURNAL OF EMERGENCY NURSING/Levins reduce the diagnostic ability of CT scanning in critically injured patients. Overview and advantages of ultrasound The need for a rapid, noninvasive assessment tool for the diagnosis of intra-abdominal injury has led to interest in ultrasound. Ultrasound involves sound waves at frequencies above the range of human hearing: 20,000 cycles per second, or 20 khz. Ultrasound originated in the 1930s with the advent of sonar to enable the United States military to detect underwater objects such as submarines. 9 At its outset, ultrasound used the A-mode (amplitude modulation), which provided a single-image, 1-dimensional echo. In the 1960s, with the advent of the B-mode (brightness modulation), a 2-dimensional echo became available. 10 In the early 1980s, the mode of real-time ultrasound became available. Real-time ultrasound produced 15 to 30 images per second, which allowed a significant increase in the quantity and quality of images. 11 It also allowed for detection of movement within the abdomen. Various authors have stated that a minimum of 20 to 100 ml of free fluid must be visible on ultrasound to make a diagnosis of hemoperitoneum. When more than 200 ml was present, the diagnosis of hemoperitoneum was virtually assured. The initial medical utilization was crudely adapted from the military technology in the 1940s by Gohr and Wedekind to identify cranial abnormalities. 12 The first use in obstetrics and gynecology was by Wild and Weit in the 1950s. 13 In 1963, Holmes and Howry 14 first used ultrasound in diagnosing abdominal disease, and Goldberg et al 15 used ultrasound to identify ascitic fluid in Only recently has the surgical community within the United States expressed interest in ultrasound. This level of interest differs markedly from our surgical counterparts in Europe and Japan, where ultrasound is performed by the examining physician at the bedside. The German Association for Surgery has required education in ultrasound for its residents since 1988, and only candidates experienced in ultrasound may sit for national board examination. 16 Initial studies evaluating the use of ultrasound in abdominal trauma also came from Europe. In 1981, Halfbass et al 17 evaluated 190 trauma patients and correctly identified 24 of 25 cases of hemoperitoneum. Aufschnaiter and Kofler 18 evaluated a series of 128 trauma patients in which the conclusion was reached that all clinically relevant cases of hemoperitoneum were identified. In the late 1980s, the American surgical community began to see abdominal ultrasound as a viable diagnostic modality. The initial studies of Rozycki et al 19 and Tso et al 20 verified what our European counterparts had known for years: Diagnostic ultrasound in blunt abdominal trauma is effective in diagnosing life-threatening hemoperitoneum. One common point found throughout the literature is the effect of operator experience with this diagnostic modality. Increased experience with ultrasound equates with increased accuracy. Many institutions using ultrasound offer initial training for surgical residents in basic ultrasound. This initial training is supplemented by actual hands-on performance of ultrasound under the guidance of an attending surgeon. Numerous courses also are offered by individual groups such as the American College of Emergency Physicians, the Eastern Association for the Surgery of Trauma, and the Society for Academic Emergency Medicine. Increased training and experience result in greater accuracy. Rozycki et al 21 found that an attending trauma surgeon who had completed at least 200 ultrasound examinations had a false-negative rate of 0%. Focused assessment sonogram for trauma As utilization of ultrasound increased, the focused assessment sonogram for trauma (FAST) was developed. Numerous studies have shown that the FAST technique has a sensitivity of 93%, a specificity of 98%, and an accuracy of 97% for identifying intraabdominal hemorrhage. These data compare favorably with DPL, CT, and radiologist-performed ultrasound. 21 FAST is an extension of the physical examination that is performed by the trauma surgeon as a part of the primary examination after the airway, breathing and circulation (ABCs) have been completed in the hemodynamically unstable patient. In the hemodynamically stable patient, the FAST survey is completed as a part of the secondary survey. The FAST survey should be completed in about 2.5 minutes. 22 The purpose of the FAST survey is to identify free fluid within the abdominal cavity, surrounding the heart, and within both hemithoraces, not organ-specific imaging. Various authors have stated that a minimum of 20 to 100 ml of free fluid must be visible on ultrasound to make a diagnosis of hemoperitoneum. 16 Volume 26, Number 1

3 Levins/JOURNAL OF EMERGENCY NURSING Table 1 Advantages and disadvantages of ultrasound Advantages 1. Rapid implementation 2. Noninvasive 3. No contrast administration is required 4. Repeatable, portable 5. With experienced surgeons, ultrasound has an accuracy and sensitivity that approaches DPL and CT Disadvantages 1. Requires frequent utilization to obtain proficiency 2. Large amounts of intraluminal air and subcutaneous air limit visualization 3. Morbid obesity limits visualization 4. Not organ specific Image available in print only. DPL, Diagnostic peritoneal lavage; CT, computed tomography. When more than 200 ml was present, the diagnosis of hemoperitoneum was virtually assured. 23 The diagnosis of hemothorax by ultrasound has been found to be very accurate, and fluid collections of as little as 20 ml can be detected by ultrasound. However, because pneumothorax is not visible on ultrasound, a chest radiograph is still mandatory. 24 The most common reasons given for not using ultrasound were lack of surgeon interest, political infighting among various departments, and a lack of funding for equipment. The FAST surveys for blood in the pericardial sac surrounding the heart (epigastric view) and in 3 dependent regions of the abdomen: Morrison s pouch in the right upper quadrant (hepato-renal recess), which is the most posterior abdominal compartment in the supine patient, the spleno-renal recess in the left upper quadrant, and the pouch of Douglas in the pelvis (supra-pubic view) (Figure 1). Both upper quadrant abdominal views also allow for the detection of hemothoraces. Gastric decompression may be performed before initiation of ultrasound; however, urinary catheterization should be withheld, allowing the full bladder to provide an acoustic window for easier visualization of blood within the pelvis. 25 Figure 1 Transducer positions for the focused assessment for the sonographic examination of the trauma patient. (Reproduced with permission from Rozycki GS. The role of surgeon performed ultrasound in patients with possible cardiac wounds. Annals of Surgery 1996; 223:738.) Utilization of the FAST survey should, in the hands of an experienced trauma surgeon, quickly and reliably rule out the abdominal compartment, pericardial sac, or hemithorax as the location of life-threatening blood loss. However, it is not organ specific and does not rule out the potential for isolated injury not resulting in significant hemoperitoneum, pericardial tamponade, or hemothorax. For advantages and disadvantages of ultrasound, see Table 1. In the case of a hemodynamically stable patient with multiple injuries, a positive ultrasound does not mandate immediate operative intervention. A CT scan to allow organ specificity and grading of injury is indicated. Continued serial physical assessment and repeat ultrasound and CT scanning should also be used. Current regional use of ultrasound To assess the use of ultrasound in blunt trauma, a telephone survey of 21 trauma centers (both level 1 and 2) in the Delaware Valley area was conducted by the author in March This survey found that 15 February

4 JOURNAL OF EMERGENCY NURSING/Levins Table 2 Preparing for the FAST examination 1. Ensure that the primary assessment and treatment is completed quickly and appropriately. Remember the FAST survey may be a part of the primary survey in the hemodynamically unstable patient (after the ABCs) or a part of the secondary survey in the hemodynamically stable patient. 2. Remember, gastric decompression is okay. Withhold Foley catheter insertion until ultrasound is completed. (A full bladder makes fluid identification in the pelvis easier). 3. Room-temperature gel is cold; it should be warmed if possible. 4. Whereas exposure of the patient is important, areas not necessary for evaluation should be covered with warm blankets to maintain patient dignity and to help minimize hypothermia. 5. Be prepared in light of positive findings for rapid transport of the patient to the operating room. FAST, Focused assessment sonogram for trauma; ABCs, airway, breathing, and circulation. centers used ultrasound for diagnosing abdominal trauma. In most of these centers, the ultrasound was performed at the bedside by the trauma attending physician; however, a few centers used the radiology department. Of the centers using the radiology department, one maintained 24-hour radiologist coverage as a member of the trauma team while the others used radiology during normal business hours. After hours, either the trauma attending physician or ED attending physician performed necessary ultrasound. In 2 centers, ultrasound is only performed during the day with radiology support. In centers not using ultrasound, 5 of the 6 maintained level 2 trauma center status, and 2 of these 6 plan to utilize ultrasound in the near future. The most common reasons given for not using ultrasound were lack of surgeon interest, political infighting among various departments, and a lack of funding for equipment. One center stated that a new spiral CT machine located in close proximity to the emergency department was used instead of ultrasound. In comparing cost-effectiveness between CT scanning, DPL, and ultrasound, some interesting findings emerge. Whereas cost varies from center to center depending upon equipment used, the charge for an abdominal CT scan ranges from $400 to $1200. The charge for a DPL ranges from $200 to $650. These figures are for the procedures themselves and do not include professional fees or additional charges. The charge for ultrasound in many centers is nothing, although this obviously does not take into account the capital expense of the ultrasound equipment. Many centers are currently not billing for physician-performed ultrasound in the trauma population. One of the main reasons given is the lack of widespread acceptance of ultrasound as a diagnostic modality. Possibly, as ultrasound becomes more common and accepted as a diagnostic modality, it too will entail a charge. Currently this lack of charge makes ultrasound far and away more cost-effective compared with CT scanning and DPL. The charge for an abdominal CT scan ranges from $400 to $1200. The charge for a DPL ranges from $200 to $650. These figures are for the procedures themselves and do not include professional fees or additional charges. The charge for ultrasound in many centers is nothing. As new technology continues to evolve and ultrasound becomes more widely accepted, the trauma community in general must have some understanding of the role diagnostic ultrasound can play in the initial assessment and treatment of trauma patients. While emergency nurses role in performing this examination is limited, there are some responsibilities that all members of the trauma team share (Table 2), and nurses directly involved in the care and resuscitation of trauma victims are critically important to the process. Persons providing care for trauma patients need to know what ultrasound is, how this technology has evolved, and what its advantages and limitations are. References 1. Root HD. Abdominal trauma and diagnostic peritoneal lavage revisited. Am J Surg 1990:159: Powell DC, Bivins BA, Bell RM. Diagnostic peritoneal lavage. Surg Gynecol Obstet 1982;155: Soderstrom CA, DuPriest RW, Cowley RA. Pitfalls of peritoneal lavage in blunt abdominal trauma. Surg Gynecol Obstet 1980;151: Cox EF. Blunt abdominal trauma: a 5 year analysis of 870 patients requiring celiotomy. Ann Surg 1984;199: Volume 26, Number 1

5 Levins/JOURNAL OF EMERGENCY NURSING 5. Federle MP, Crass RA, Jeffrey RB, Trunkey D. Computed tomography in blunt abdominal trauma. Arch Surg 1982; 117: Thal ER, Meyer DM. The evaluation of blunt abdominal trauma: computed tomography scan, lavage or sonography. Adv Surg 1991;24: Trunkey D, Federle MP. Computed tomography in prospective. J Trauma 1986;26: Dauterive AH, Flanebaum L, Cox EF. Blunt intestinal trauma. Ann Surg 1985;201: Bushong SC. The physics and biology of diagnostic ultrasound. In: Athey PA, Hadlock FP, editors. Ultrasound in obstetrics and gynecology. St Louis (MO): Mosby; p Ziskin MC. Basic physics of ultrasound. In: Fleischer AC, Romero R, Manning FA, Jeanty P, James AE, eds. The principles and practice of ultrasonography in obstetrics and gynecology. 4th ed. Norwalk (CT): Appleton and Lange; p Cooperberg PL, Li DKB, Sauerbrei EE. Abdominal and peripheral applications of real time ultrasound. Radiol Clin North Am 1980;18: Tiling T, Bouillon B, Schmid A, et al. Ultrasound in blunt abdomino-thoracic trauma. In: Border JR, Allgöwer M, Hansen ST Jr, Rüedi TP, editors. Blunt multiple trauma: comprehensive pathophysiology and care. New York: Marcel Dekker; Howry DH, Bliss WR. Ultrasonic visualization of soft tissue structures of the body. J Lab Clin Med 1952;40: Holmes JH, Howry DH. Ultrasonic diagnosis of abdominal diseases. Am J Diagnostic Dis 1963;8: Goldberg BB, Clearfield HR, Goodman GA. Evaluation of ascites by ultrasound. Radiology 1970;96: Wening JV. Evaluation of ultrasound, lavage and computed tomography in blunt abdominal trauma. Surg Endosc 1989;3: Halbfass HJ, Wimmer B, Hauenstein K, Zavisic D. Ultrasonic diagnosis of blunt abdominal injury. Fortschr Med 1981;99: Aufschnaiter M, Kofler H. Sonographische Akutdiagnostik Beim Polytrauma. Akt Traumatol 1983;13: Rozycki GS, Ochsner MG, Schmidt JA, Frankel HL, Davis TP, Wang D, et al. A prospective study of surgeon performed ultrasound as the primary adjuvant modality for injured patient assessment. J Trauma 1995;39: Tso P, Rodriguez A, Cooper C, Militello P, Mirvis S, Badellino M. Sonography in blunt abdominal trauma: a preliminary progress report. J Trauma 1992;33: Rozycki GS, Shackford SR. Ultrasound, what every trauma surgeon should know. J Trauma 1996;40: Rozycki GS. Ultrasound as used in thoracoabdominal trauma. Surg Clin North Am 1998;78: Akio K, Toshibumi O. Emergency center ultrasonography in the evaluation of hemoperitoneum: a prospective study. J Trauma 1991;31: Rothlin M, Naf R, Amgwerd M, Candinas D, Frick T, Trentz O. Ultrasound in blunt abdominal and thoracic trauma. J Trauma 1993;34: Rozycki GS, Ochsner MG, Jaffin JH, Champion HR. Prospective evaluation of surgeons use of ultrasound in the evaluation of trauma patients. J Trauma 1993;34:517. February