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CHAPTER 263:  Abdominal Trauma      1751 FIGURE 262-5. CT scan of traumatic aortic injury. A. Axial CT scan showing mediastinal hematoma (open arrow) and irregularity and thrombus in the aorta (closed arrow). B. Sagittal  CT  scan  of  same  patient  with  pseudoaneurysm  (arrow)  from  tear  in  aorta  distal  to  left subclavian artery. FIGURE 262-6. Angiogram of the same patient in Figur e 262-5 showing pseudoaneurysm (open arrow) and irregular lumen (closed arrow) of injured aorta. results because a clot or an intimal flap may close the luminal defect. The overall complication rate of angiography has remained at about 25%, but rates for serious complications, such as amputation and death, remain low at 0.1% and 0.3%, respectively. TREATMENT OF GREAT VESSEL INJURY Consult a trauma or vascular surgeon at the time of initial suspicion of great vessel injury or immediately upon diagnosis. Transport patients with great vessel injury who exhibit hemodynamic instability, profound hemorrhage from chest tubes, and radiographic evidence of a rapidly expanding mediastinal hematoma immediately to the operating room. Immediate surgical repair may not be possible in all patients. Patients with instability from other injuries, such as from intra-abdominal injuries or severe closed head injuries, may require a delayed repair due to the severity of these other life-threatening issues. Some elderly patients may have comorbidities that require medical management prior to surgery. Pharmacologic control of blood pressure and heart rate is extremely important when delayed or nonoperative manage ment is contemplated. 2,77 Avoid large swings in blood pressure that may increase vessel-shearing forces in patients who are hemodynamically stable. Administer β-adrenergic blocking agents, sedatives, analgesics, and vasodilators as needed to keep the patient’s heart rate and systolic blood pressure at appropriate levels. Use autotransfusion devices in cases of large bleeding vessels if available. Traumatic aortic injuries can be partial thickness (as in the classic intimal flap of aortic dissection) or full thickness with containment by surrounding structures. These histopathologic entities mandate a similar therapeutic approach as aortic dissection. Decreasing the slope of the dP/dT (change in pressure over the change in time) will decrease wall tension and shearing forces. This may lead to permissive hypoten sion and bradycardia as a treatment and temporizing measure in aortic disruption. Maintain systolic blood pressure in the 100 to 120 mm Hg range with a heart rate around 60 beats/min. This will decrease the shearing forces on the internal lumen. Patients should not perform any maneuver, like a Valsalva, that will increase intrathoracic pressure. Titrating a short-acting β-blocker, such as esmolol, can decrease the heart rate. Once the heart rate is controlled, an arterial vasodilator, such as a calcium channel blocker or sodium nitroprusside, can be added to help control the blood pressure. A vasodilating calcium channel blocker such as nicardipine or clevidipine is recommended over sodium nitroprusside. Do not use sodium nitroprusside alone due to the reactive tachycardia associated with its administration. 2,6 Acknowledgments: The authors thank Christopher Ross and Theresa Schwab for their contributions to this chapter in the prior edition. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Abdominal Trauma Anthony A.

one due to the reactive tachycardia associated with its administration. 2,6 Acknowledgments: The authors thank Christopher Ross and Theresa Schwab for their contributions to this chapter in the prior edition. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Abdominal Trauma Anthony A. Ferroggiaro O. John Ma INTRODUCTION Abdominal trauma accounts for 15% to 20% of all trauma deaths. 1 Although the liver is the most frequently injured abdominal organ, the spleen is the most frequently injured intra-abdominal organ from sports accidents. 2 Death may occur as a consequence of massive hemorrhage and generally results in early demise soon after the injury. Patients who survive the initial traumatic insult are at risk for infection and sepsis. CHAPTER Tintinalli_Sec21_p1669-1766.indd 1751 8/1/19 12:22 PM

injured intra-abdominal organ from sports accidents. 2 Death may occur as a consequence of massive hemorrhage and generally results in early demise soon after the injury. Patients who survive the initial traumatic insult are at risk for infection and sepsis. CHAPTER Tintinalli_Sec21_p1669-1766.indd 1751 8/1/19 12:22 PM 1752 SECTION 21: Trauma  SOLID ORGAN INJURIES Signs and symptoms of a solid organ injury are generally due to pain and blood loss. Exclusive reliance on the Advanced Trauma Life Sup port shock classification may lead to underrecognition of progressive instability. 5 In general, early intra-abdominal hemorrhage may result in minimal change in vital signs. As blood loss continues, heart and respi ratory rate increase and urinary output drops. Patients may also become anxious and confused. Hypotension may not occur until the circulating blood volume significantly decreases. Hepatic and splenic injuries are at high risk for hemorrhage in both penetrating and blunt abdominal trauma. Any blunt abdominal trauma patient with diffuse peritonitis or who is hemodynamically unstable should be taken urgently for laparotomy. 6,7 Hepatic and splenic injuries are graded; low grades indicate less severe injury. CT imaging has improved the definition of injuries, and combined with the development of interventional radiology and catheter-based vascular management, many patients with hepatic or splenic injuries are managed nonoperatively. Surgical consultation is required in any solid organ injury; transfer to a level 1 trauma center reduces mortality. 8 Delayed rupture can occur in splenic and hepatic injuries, and at times, pain with solid organ injury may be referred to the shoulder/scapular region.  HOLLOW VISCUS AND MESENTERIC INJURIES In blunt abdominal trauma, the incidence of blunt bowel and mesenteric injuries is infrequent (1% to 12%). 9,10 Hollow viscus injuries produce symptoms from the combination of blood loss and peritoneal contami nation by GI contents. Hemorrhage from a mesenteric injury may be minimal and not be obvious on physical exam. Chemical irritation of the peritoneum from gastric acid contents may produce immediate pain, although bacterial contamination of the abdominal cavity may result in delayed signs and symptoms. Delays in diagnosis and operative management are associated with an increase in mortality.  RETROPERITONEAL INJURIES The retroperitoneal structures discussed in this chapter include the pancreas (excluding the tail) and duodenum. See Chapter 265, “Genitourinary Trauma” for a discussion of kidney, ureter, and bladder injuries. Pancreatic injuries infrequently occur (4%) with abdominal trauma, yet are associated with significant morbidity and mortality. 11 Pancreatic trauma often occurs from rapid deceleration, such as unrestrained drivers who hit the steering column or bicyclists who fall against a handle bar, and these patients are at risk for pancreatic injuries. Similarly, duodenal injuries may be relatively asymptomatic and go undiagnosed. As the duodenal hematoma expands, signs and symptoms of obstruction may develop (abdominal pain, distention, and vomiting). Duodenal rupture generally occurs following high-velocity deceleration. The ruptured contents may be contained within the retroperitoneum and missed with studies that investigate the peritoneum exclusively. Fever and leukocytosis herald the development of an abscess or sepsis.  DIAPHRAGMATIC INJURIES Diaphragmatic injuries are uncommon (0.8% to 5% of patients with thoracoabdominal injury). Diaphragmatic injury diagnosis is often delayed in blunt trauma due to concomitant severe injuries and may be incidentally identified during operative treatment for hemodynamic instability.

ess or sepsis.  DIAPHRAGMATIC INJURIES Diaphragmatic injuries are uncommon (0.8% to 5% of patients with thoracoabdominal injury). Diaphragmatic injury diagnosis is often delayed in blunt trauma due to concomitant severe injuries and may be incidentally identified during operative treatment for hemodynamic instability. 12 CT imaging has variable sensitivity and specificity (ranging to a low of 60% and 70%, respectively). Delayed diagnosis may lead to herniation or strangulation of abdominal contents through the dia phragmatic defect, with mortality rates up to 50%. DIAGNOSIS Although multiple diagnostic modalities exist to detect intra-abdominal injuries, no study is fail-proof. Therefore, a combination of careful physical exam, attention to the mechanisms and circumstances of injury, and judicious selection of diagnostic studies is used for diagnosis. PATHOPHYSIOLOGY  BLUNT ABDOMINAL TRAUMA In blunt trauma, all abdominal structures are at risk, and ultimately the biomechanics of the traumatic force determine which organs are affected. Compressive, shearing or stretching, and acceleration/decel eration forces impact the abdominal cavity and structures leading to abdominal wall, solid organ, or hollow viscous injuries. Abdominal organs may be relatively mobile or fixed. Injury is common in transition areas between these structures, such as the ligament of Treitz, where mesenteric or small bowel injuries may occur. The most common mechanism for blunt abdominal trauma is a motor vehicle collision. 1 Falls, second in frequency as causes of blunt trauma, produce injury due to the fall distance, the impact surface, and the manner of surface impact. Both solid and hollow organ rupture can occur with retroperitoneal injury and hemorrhage resulting when the force is transmitted along the axial skeleton. 3 Pedestrians struck by vehicles or motorcyclists and bicyclists who crash generally have no protection to their abdomen and are at high risk for intra-abdominal injuries.  PENETRATING ABDOMINAL TRAUMA Stab and gunshot wounds produce injury as the foreign object passes through tissue. With gunshot wounds, there may be additional injury from the transmitted energy of the blast. Furthermore, gunshot wounds create secondary missiles such as fragmented bone that may increase the traumatic burden. The length, trajectory, and fragmentation of the penetrating object will not necessarily be known during the evaluation. Therefore, assume any penetrating injury to the chest, pelvis, flank, or back to have penetrated the abdominal cavity until proven otherwise. CLINICAL FEATURES Clinical signs may be obvious (such as evisceration) or occult. Fac tors making the diagnosis of an abdominal injury challenging include concomitant injuries (particularly significant head injuries), referred pain, intoxication with alcohol or other toxicologic substances, or lan guage barriers. Y oung, healthy patients may be able to compensate for intra-abdominal hemorrhage before clinical signs become overt. Elderly patients may be on anticoagulation medications or on medications limiting physiologic response, such as antihypertensives (beta-blockers or calcium channel blockers).  PHYSICAL EXAMINATION Inspect the abdomen for external signs of trauma (e.g., abrasions, lacerations, contusions, seatbelt marks). A normal-appearing abdomen does not exclude serious intra-abdominal injury. Following inspection, pal pate the abdomen in all quadrants, making note of general or regional tenderness and signs of acute abdomen (rigidity, rebound, guarding). Regardless of imaging, document serial exams for patients who remain in the ED for several hours. A traumatic abdominal process may progress over hours, and new symptoms and signs may indicate the development of a surgical process.

general or regional tenderness and signs of acute abdomen (rigidity, rebound, guarding). Regardless of imaging, document serial exams for patients who remain in the ED for several hours. A traumatic abdominal process may progress over hours, and new symptoms and signs may indicate the development of a surgical process. Reliance on physical exam alone, particularly with a worrisome mechanism of injury, may result in an unacceptably high misdiagnosis rate or delay in treatment. As many as 45% of blunt trauma patients thought to have a benign abdomen on initial physical exam are later found to have a significant intra-abdominal injury.  ABDOMINAL WALL INJURIES Contusions of the abdominal wall musculature may result either from a direct blow or indirectly via a sudden muscular contraction. Symptoms include pain and possibly soft tissue swelling or a hematoma. Abdominal wall injuries may mimic or implicate more extensive intra-abdominal injury. Imaging may be indicated to “rule out” intra-abdominal injury. Tintinalli_Sec21_p1669-1766.indd 1752 8/1/19 12:22 PM

indirectly via a sudden muscular contraction. Symptoms include pain and possibly soft tissue swelling or a hematoma. Abdominal wall injuries may mimic or implicate more extensive intra-abdominal injury. Imaging may be indicated to “rule out” intra-abdominal injury. Tintinalli_Sec21_p1669-1766.indd 1752 8/1/19 12:22 PM CHAPTER 263:  Abdominal Trauma      1753 Hemodynamic instability may limit the immediate use of some diag nostic testing (CT). The FAST examination has become integral to early resuscitation and the diagnostic algorithms of abdominal trauma patients. Indications to consider an expanded abdominal trauma evaluation are listed in Table 263-1. Often these evaluations include laboratory testing, imaging, further resuscitation, and reevaluation. Trauma service consultation may be invaluable.  ULTRASONOGRAPHY The FAST examination is a widely accepted primary diagnostic study. The underlying premise of the FAST exam is that many clini cally significant injuries will be associated with free intraperitoneal fluid (Figure 263-1). The greatest benefit of FAST is the rapid identification of free intraperitoneal fluid in the hypotensive patient with blunt abdominal trauma. The FAST examination is accurate, rapid, noninvasive, repeatable, and portable, and involves no nephrotoxic contrast material or ionizing radiation. Massive hemoperitoneum is quickly detected with a single view of Morison’s pouch. FAST also evaluates for free pericardial or pleural fluid and for pneumothorax. The main disadvantage of US compared to CT is the inability to identify the exact source of free intraperitoneal fluid. Other potential disad vantages of the FAST examination are the operator-dependent nature of the examination, the difficulty in interpreting the images in patients who are obese or have subcutaneous air or excessive bowel gas, and the difficulty in distinguishing intraperitoneal hemorrhage from ascites. Also, the FAST examination cannot evaluate the retroperitoneum as well as CT. Therefore, US and CT are complementary rather than competing technologies when time and stability permit, and the potential benefits of CT outweigh the risks. Beyond diagnosis, US can be a clinically helpful tool for trauma resuscitation. US may guide the placement of central venous catheters, suprapubic catheters, and large-bore peripheral lines. The inferior vena cava diameter of trauma patients, as measured on initial CT imaging, is a marker of intravascular volume and a predictor of mortality, 13,14 although the reliability of inferior vena cava diameter measurement is still debated. 15,16 Because the FAST examination can reliably detect small amounts of free intraperitoneal fluid and can estimate the rate of hemorrhage through serial examinations, US has replaced diagnostic peritoneal lavage (DPL) for blunt abdominal trauma in the majority of North American trauma centers. A positive DPL in isolation is no longer an absolute indication for exploratory laparotomy; the amount of hemor rhage and the hemodynamic status of the patient are important factors for determining further management steps.  COMPUTED TOMOGRAPHY Abdominopelvic CT with IV contrast is the noninvasive gold standard study for the evaluation of abdominal injury (unless the patient has allergy to iodinated contrast). The addition of PO contrast can result in aspiration and is too time-consuming to be practical in trauma management. The major advantage of IV contrast CT over other diagnostic modalities is that the precise location(s) of specific injury can be identified ( Figure 263-1). CT can quantify and differentiate the amount and type of free fluid in the abdomen. CT can also evaluate for retroperitoneal injuries; it is the ideal study for assessment of the duodenum, pancreas, and vascular and renal systems.

ies is that the precise location(s) of specific injury can be identified ( Figure 263-1). CT can quantify and differentiate the amount and type of free fluid in the abdomen. CT can also evaluate for retroperitoneal injuries; it is the ideal study for assessment of the duodenum, pancreas, and vascular and renal systems. The use of multiphasic CT (arterial, portal, and equilibrium phases) accurately identifies lifethreatening mesenteric hemorrhage and transmural bowel injuries. 9 CT evidence of a flat inferior vena cava suggests hypovolemia. With a focus on patient safety, source EDs should transmit completed imaging with patient transfer to avoid repeat CT imaging whenever possible. Outcomes and time to definitive care are not significantly improved when imaging is repeated at the accepting trauma center.  DIAGNOSTIC PERITONEAL LAVAGE Despite the reproducibility and prospectively validated sensitivity of DPL to diagnose intraperitoneal injury, the advent and acceptance of other diagnostic modalities have significantly reduced the frequency of DPL. DPL can be performed using a closed ( Figure 263-2) or open tech nique. However, the open DPL technique requires advanced training and expertise. Some advocate the use of DPL in the hemodynamically FIGURE 263-1. Hemoperitoneum. The abdominal IV contrast CT. A. A fractured spleen with surrounding hematoma is demonstrated, but a small stripe of fluid is also present above the  right  kidney  in  Morison’s  pouch. B. A  right  intercostal  oblique  US  view  from  the  same patient reveals a thin stripe of fluid in Morison’s pouch. [Reproduced with permission from Ma OJ, Mateer JR, eds: Ma and Mateer’s Emergency Ultrasound, 3rd ed. © 2014, McGraw-Hill, Inc. New York.] TABLE 263-1 Abdominal Injuries That Need Expanded Evaluation •  Presence  of abdominal pain, tenderness, distention, or external signs of trauma •  Mechanism  of injury with a high likelihood of causing an abdominal injury •  Suspicious  lower chest, back, or pelvic injury •   Inability to tolerate a delayed diagnosis (e.g., patients who are elderly, on anticoagulants, or have liver cirrhosis/portal hypertension) •  Presence  of distracting injuries •  Altered  consciousness/sensorium (e.g., CNS injury, intoxicating substances) Tintinalli_Sec21_p1669-1766.indd 1753 8/1/19 12:22 PM

injury •   Inability to tolerate a delayed diagnosis (e.g., patients who are elderly, on anticoagulants, or have liver cirrhosis/portal hypertension) •  Presence  of distracting injuries •  Altered  consciousness/sensorium (e.g., CNS injury, intoxicating substances) Tintinalli_Sec21_p1669-1766.indd 1753 8/1/19 12:22 PM 1754 SECTION 21: Trauma unstable patient with concern for intra-abdominal injury when the FAST exam is negative or unavailable.18  DIAGNOSIS IN PENETRATING TRAUMA The same diagnostic tools are available for evaluation of intraperitoneal injury in the patient with penetrating trauma (CT, US, and DPL). Mandatory exploration for patients sustaining a stab wound to the abdomen has yielded unacceptably high rates of nontherapeutic laparotomy, 19 yet physical exam alone can miss important intra-abdominal injuries. The emergency physician or consultant surgeon may locally explore anterior abdominal stab wounds (Figure 263-3) to assess for violation of the peritoneum.20 Patients with transabdominal gunshot wounds almost always have intra-abdominal injuries. In the hemodynamically stable patient with penetrating trauma, CT can help guide the surgeon for operative versus nonoperative management. TREATMENT  LAPAROTOMY Laparotomy remains the gold standard therapy for significant intraabdominal injuries. It is definitive, rarely misses an injury, and allows for complete evaluation of the abdomen and retroperitoneum. Table 263-2 describes generally accepted indications for exploratory laparotomy. All patients with persistent hypotension, abdominal wall disruption (peritoneal violation), or peritonitis need surgical exploration. In addition, the presence of extraluminal, intra-abdominal, or retroperitoneal air on plain radiograph or CT should prompt surgical exploration. Early surgical involvement in decision making and resuscitation may be valuable in blunt abdominal trauma patients; in smaller medical centers or community hospitals, transfer to a trauma center may best serve such patients.  NONOPERATIVE MANAGEMENT OF BLUNT TRAUMA Nonoperative management of trauma patients has been greatly advanced by the evolution of CT. CT can make the diagnosis of solid organ injury along with ruling out other injuries requiring surgery. Solid visceral injuries are graded according to their severity. Both the Eastern Association for the Surgery of Trauma and the Western Trauma Association have published guidance on nonoperative management of blunt abdominal trauma. Nonoperative management is now the treatment of choice in hemodynamically stable blunt hepatic and splenic injured patients “irrespective of the grade of injury, patient age, or the presence of associated injuries. ” Several technologic advances have increased the sophistication of nonoperative therapy. The increased resolution of helical CT can iden tify intraparenchymal vascular injuries (i.e., pseudoaneurysms or arte riovenous fistulae) and active extravasation of contrast, further defining Guidewire through needle Catheter over guidewire FIGURE 263-2. Closed diagnostic peritoneal lavage. Drain the urinary bladder. Infiltrate the  area  just  below  the  umbilicus  with  lidocaine  and  epinephrine. Insert  the  needle  two fingerbreadths below the umbilicus. Aspirate directly with a syringe attached to the needle, or  insert  a  guidewire  into  the  abdomen  and  place  the  peritoneal  lavage  catheter  over  the guidewire. Instill 1 L of normal saline through the catheter, and then aspirate. FIGURE 263-3. Local  abdominal  wound  exploration  for  anterior  abdominal  stab wounds. This is a surgical procedure requiring expertise, proper instrumentation, and lights. Use only for anterior abdominal stab wounds.

theter  over  the guidewire. Instill 1 L of normal saline through the catheter, and then aspirate. FIGURE 263-3. Local  abdominal  wound  exploration  for  anterior  abdominal  stab wounds. This is a surgical procedure requiring expertise, proper instrumentation, and lights. Use only for anterior abdominal stab wounds. Widen the stab wound and explore down to the level of the fascia to determine if the anterior fascia and/or posterior fascia have been violated. TABLE 263-2 Indications for Laparotomy Blunt Penetrating Absolute Anterior abdominal injury with hypotension Abdominal wall disruption Peritonitis Free air under diaphragm on chest radiograph Positive FAST or DPL in hemodynamically unstable patient CT-diagnosed injury requiring surgery Injury to abdomen, back, and flank with hypotension Abdominal tenderness GI evisceration High suspicion for transabdominal trajectory after gunshot wound CT-diagnosed injury requiring surgery Relative Positive FAST or DPL in hemodynamically stable patient Solid visceral injury in stable patient Hemoperitoneum on CT without clear source Positive local wound exploration after stab wound Abbreviations: DPL = diagnostic peritoneal lavage; FAST = focused assessment with sonography for trauma. Tintinalli_Sec21_p1669-1766.indd 1754 8/1/19 12:22 PM