Chapter 17
Abdominal Trauma
Jameel Ali
Chapter Overview
Missed or delayed diagnosis of intra-abdominal injuries accounts for a major cause of preventable deaths in trauma patients1 because of the many diagnostic challenges in these patients. Management or monitoring in the intensive care unit (ICU) could potentially decrease this risk. In order to accomplish this, the surgical intensivist requires a clear understanding of the clinical features of initial presentation, the likelihood of change occurring later in the patient’s course, general principles of abdominal trauma management as well as management of specific injuries affecting the intraabdominal contents. These patients, particularly with blunt trauma may be difficult to assess because of altered sensorium (from drugs, alcohol, or head injury), altered sensation (from spinal injury), and injury to adjacent structures (pelvis, chest) that may present with abdominal findings.2 ICU admission allows close observation during the preoperative as well as postoperative period during which important changes could occur that would prompt changes in management strategy including a return to the operating room (OR).
In this chapter, general principles of management of abdominal injuries are followed by description of the role of adjunctive studies and principles of management of specific injuries to guide the intensivist in caring for these patients.
General Principles
Abdominal injuries may be classified into two broad categories: blunt and penetrating which differ from each other in significant ways.
Penetrating injury may result from stabs or other sharp instruments, or from bullet or shotgun. Stab wounds tend to be the least serious because the organs involved are only those within the trajectory of the wounding instrument and surrounding organ injury is absent. Unless the stab wound penetrates a vascular structure directly, major hemorrhage is not as likely as in other forms of penetrating or blunt injury. Penetrating injuries from bullets or shotguns produce unpredictable injuries because of their variable trajectory since a straight line joining the points of entry and exit does not represent the path of the missile and multiple organ involvement is common. Low velocity missiles create less damage than high velocity missiles because of the lower kinetic energy transfer. In shotgun injuries much less damage occurs when the injury is sustained from far range than close range.
Blunt injury results from a crushing force producing irregular lacerations with multiple organ involvement. Diagnosis is more challenging and the treatment approach needs to be more aggressive because morbidity and mortality from major hemorrhage, devitalization of tissue and complications such as sepsis are much higher than in penetrating injuries.
The frequency of organ involvement is also different between penetrating and blunt injuries. In penetrating injuries the order of frequency of organ involvement is: liver, small bowel, stomach, colon, major vessels, and retroperitoneum. In blunt injuries the order is spleen, kidney, liver, and intestines.
Because of the variability in location of the diaphragm with the phases of respiration and the unpredictable trajectory of penetrating wounds to the abdominothoracic areas, it is prudent to consider the possibility of intraabdominal injuries in all patients in whom there is impact to the chest or abdomen. In a hemodynamically compromised trauma patient, when the therapeutic decision is unclear, the combination of physical examination, chest X-ray, and chest tube insertion will frequently allow determination of whether the causative lesion is in the chest. With a negative chest X-ray and no chest tube drainage in the absence of cardiac tamponade or traumatic air embolism laparotomy should be considered to identify and treat a possible intra-abdominal cause of the hemodynamic compromise.
The entire abdomen, chest, and upper thigh should be prepped and draped in preparation for the laparotomy to allow access to both the abdomen and chest as well as to deal with possible lesions in either cavity, access to the supradiaphragmatic aorta for temporary control of massive intraperitoneal hemorrhage as well as access to the groin for possible venous graft harvesting. In most instances where abdominal aortic control is deemed necessary, this is accomplished through the intra-abdominal approach. Preoperative antibiotics to cover aerobic and anaerobic organisms should be administered preferably prior to the incision3 to prevent septic complications. In the absence of fecal contamination, the antibiotics should not be continued after the operation. However, when there is contamination, antibiotics should be continued until the temperature returns to normal without a leukocytosis. An increase in temperature and leukocytosis during antibiotic treatment or after cessation of antibiotics suggests residual sepsis often in the form of an undrained abscess warranting intervention — operative or minimally invasive — or a change in antibiotics (see chapter on Intra-abdominal Sepsis).
Although with the availability of the multitude of reliable diagnostic modalities a specific diagnosis is usually made prior to laparotomy, in most instances a specific preoperative diagnosis is not required. In general, signs suggestive of peritonitis, hemorrhage, perforation, or penetration warrant consideration for exploration of the abdomen. These signs may be elicited during assessment in the ICU.
Peritonitis is suggested by pain, localized, generalized, or rebound tenderness, guarding with or without rigidity.
Hemorrhage is detected by many modalities and depends also on the magnitude of blood loss. Intraperitoneal hemorrhage occasionally but not always results in clinical signs of peritoneal irritation. Other signs include subtle drop in Hemoglobin (Hb), tachycardia, and a decrease in urine output and in major hemorrhage, signs of shock. In blunt trauma without evidence of hollow viscus injury and with bleeding that is likely to stop spontaneously, selective nonoperative management is an acceptable option.4 Such patients must be monitored in an ICU setting with readily available surgeons to take the patient to the OR promptly when indicated by worsening of hemorrhage as manifested by a continued fall in Hb, worsening vital signs, and urine output. The threshold for laparotomy in penetrating injury with hemorrhage is much lower.
Penetration of the abdomen in stab wounds is diagnosed by wound exploration under local anesthesia. The wound is visually explored with good lighting and appropriate retractors. If it is determined that the peritoneum has been violated, in most instances laparotomy is conducted. Others have combined wound exploration with peritoneal lavage when the wound exploration suggests peritoneal penetration and if the peritoneal lavage is also positive, proceeding to laparotomy.5–7 All bullet wounds to the abdomen are generally treated by laparotomy.8 However, a selective approach which involves scanning of the abdomen and using abdominal wall radio-opaque markers has been used to identify tangential wounds which do not penetrate the peritoneum, thus, sparing laparotomy.9–10 All these patients should still be observed very carefully in the ICU for delayed signs of hollow viscus perforation which can be missed and also can occur from blast injury without evidence of peritoneal violation on imaging. The safest approach, however, is to subject all gunshot wounds to laparotomy.
In general, physical examination and history would determine the need for the trauma laparotomy. However, when the history and physical signs are equivocal, unreliable, or impossible to elicit because of neurologic deficits from drugs, spinal cord, or brain injury — ultrasound, peritoneal lavage, Computed Tomography (CT) scan, and laparoscopy are very useful adjuncts in deciding on the need for laparotomy.9–12
Role of Peritoneal Lavage, CT, Ultrasound, and Laporoscopy in Assessing Abdominal Trauma
Non-therapeutic laparotomy for penetrating abdominal trauma has been reported to be as high as nearly 60%.11 If the decision is made from wound examination the incidence of non-therapeutic laparotomy is 57%, from CT is 24%, from diagnostic peritoneal lavage is 31%, focused abdominal sonogram for trauma (FAST) is 40%, and systematic clinical assessment with blood cell count is 33%. So, clinical assessment with blood cell count which could be easily accomplished by the intensivist without need for extra imaging would result in a significant decrease in non-therapeutic laparotomy when compared to wound examination (from 57% to 33%). The most specific modality among ultrasound, CT and peritoneal lavage is CT scan. The disadvantage of CT is that it requires movement of the patient to the CT scan suite and is therefore not appropriate for hemodynamically compromised patients. The advantages of ultrasound are its portability, ease of application, repeatability, rapidity, and sensitivity but it is operator dependent and requires a well-trained experienced operator of the equipment, who does not need to be a radiologist.13 Although peritoneal lavage is very sensitive it is not very specific-this plus its relative invasiveness limits its application and in most institutions where ultrasound is immediately available, peritoneal lavage is seldom used.
Selecting the Diagnostic Modality in Blunt Abdominal Trauma
Intra-abdominal hemorrhage is the prime indication for laparotomy in blunt abdominal trauma. A diagnostic test such as ultrasound is most attractive because of its relative accuracy, rapidity, non-invasiveness, and minimal cost. However, there is still a role for other modalities such as CT and peritoneal lavage. With a negative ultrasound the patient may be observed by clinical examination. Change in the patient’s hemodynamic status warrants a repeat ultrasound or CT. In a stable patient with equivocal ultrasound findings CT should be done. An unstable patient with equivocal ultrasound should be considered for a peritoneal lavage or taken directly to the OR. When the ultrasound in a hemodynamically normal patient is positive for hemoperitoneum, CT scan should be conducted to assist in the decision for non-operative management of solid organ injury. The unstable patent with hemoperitoneum on ultrasound requires laparotomy.
There are variable results with using laparoscopy14 in abdominal trauma and there are no uniform recommendations for its use. Its most practical application is in the patient with equivocal findings who may be taken to the OR and the laparoscopy conducted prior to any planned open laparotomy with a view to abandoning the laparotomy if the laparoscopic findings do not indicate the need for a therapeutic laparotomy. When the decision for nonoperative management is made based on the above guidelines, these patients should ideally be monitored in an ICU setting unless there is another unit where the patient could be closely observed.
General Conduct of the Trauma Laparotomy
After cardiorespiratory resuscitation, usually in the emergency room, including insertion of two large bore IV’s, availability of blood and blood products, administration of fluids through a fluid warming device, insertion of a urinary and gastric catheter, insertion of an arterial line where appropriate, the patient is taken to the OR where a general anesthetic is administered, IV antibiotics administered as described, and the abdomen, chest, and groin are prepped and draped as indicated earlier. The anesthetist is notified of the intent to begin and to ensure that the fluids, including blood and blood products as well as warming and monitoring devices are ready. A generous midline incision from xiphisternum to pubis is then made.
Based on the principles enunciated in the Advanced Trauma Operative Management (ATOM) Course,15 the goals of the trauma laparotomy are to:
(1) Control hemorrhage
(2) Control contamination
(3) Definitive repair of injuries/damage control as required.
(1) Control of hemorrhage: The major cause of mortality in the multiple injured patient is hemorrhage with the major source being from abdominal trauma. The main initial focus on opening the abdomen is therefore to identify and stop bleeding while administering IV fluids. The site of the intraabdominal bleeding is frequently not immediately obvious and a systematic approach is essential. Two large suctions and sponges are used to remove blood while packing with large radio-opaque sponges, starting with packing above and below the solid organs in the upper abdomen (spleen and liver), then displacing the intestines from the lateral gutters towards the midline and packing laterally, followed by moving the bowel upward from the pelvis and tightly packing the pelvis. These maneuvers allow temporary control of the bleeding and provides the opportunity to “catch up” with fluid/blood administration. The packing is then removed in sequence and bleeding controlled by direct means as required. If on removal of packing from the liver and spleen bleeding recurs and cannot be controlled definitively it may be necessary to replace the packing and decide later whether a “damage control” approach (see in the following paragraphs) is required. Other techniques of hemorrhage control includes application of topical hemostatic agents, electro coagulation, vascular clips and agents such as the Argon beam, proximal and distal control of vessels with ligation or repair.
(2) Control of contamination: Gross spilled intestinal contents, devitalized necrotic tissue are suctioned out and perforations are identified and marked with temporary clamps, large sutures or staples initially and a decision made later as to whether formal repair, resection, anastomosis are appropriate depending on the patients overall clinical status.
(3) Definitive repair/damage control: Once hemorrhage and contamination are controlled, a reassessment of the patient’s clinical status is made, including core temperature, coagulation, hemodynamic, and acid–base status. If these parameters are acceptable then definitive surgical repair of injuries is conducted.
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