Penetrating Abdominal Trauma: Current Concepts
John R. Richards, M.D., F.A.A.E.M.
Dr. Richards is Professor, Department of Emergency Medicine, University of California, Davis Medical Center, Sacramento, California.
Within the past 12 months, Dr. Richards reports no commercial conflicts of interest.
Albert Einstein College of Medicine, CCME staff and interMDnet staff have nothing to disclose.
Release Date: 09/13/2010
Termination Date: 09/13/2013
Estimated time to complete: 1 hour(s).
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In support of improving patient care, this activity has been planned and implemented by Albert Einstein College of Medicine-Montefiore Medical Center and InterMDnet. Albert Einstein College of Medicine – Montefiore Medical Center is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.
Learning ObjectivesUpon completion of this Cyberounds®, you should be able to:
Penetrating abdominal trauma (PAT) is commonly encountered in trauma centers and combat hospitals overseas and less so in suburban and rural emergency departments. Treatment of PAT has changed over the past few decades with technological improvement in diagnostic imaging, selective non-operative management and resuscitation strategies. In this Cyberounds® we will discuss the evolution of surgical management of PAT, imaging studies such as CT and FAST, diagnosis, triage, resuscitation, disposition, and use of antibiotics and factor VIIa as it pertains to emergency physicians caring for these patients.
Treatment of PAT has changed throughout the centuries, with non-surgical management being the standard of care through World War I. This policy changed in World War II and the Korean War, in which patients with PAT frequently underwent laparotomy.(1) The standard changed once more in 1960 after Shaftan published a paper advocating "selective conservatism" for both military and civilian surgeons treating these injuries.(2) In 1968 Nance and Cohn published favorable results of this type of management in a large number of patients with stab wounds (SWs) to the abdomen.(3) The advent of imaging modalities such as CT has facilitated this conservative approach. Other techniques such as diagnostic peritoneal lavage (DPL) and local exploration, i.e., "stabogram," have been utilized to triage these patients to the operating room.(4)(5)(6)(7)(8)
Anterior abdominal GSWs represent the injuries most likely to require operative management.
Anterior abdominal GSWs represent the injuries most likely to require operative management. Anterior SWs are less predictable but stable patients may undergo local exploration and CT imaging. In 2008 Schmelzer and associates reported 25% of patients undergoing immediate surgery for PAT had no intra-abdominal injuries identified. The most common reasons for surgery in their study were for hypotension, anterior location and transaxial wounds.(6) The complication rate from laparotomy has been reported as high as 20% in the past; thus avoiding unnecessary surgery, while providing definitive care, has become the trauma surgeon's mandate. This approach has also been successful in pediatric patients with PAT.(8)
In the past, CT was somewhat limited in the diagnosis of bowel injuries. Technological advances have improved the diagnostic ability of CT to identify hollow-organ injuries.(9)(10)(11)(12) Shanmuganathan and colleagues reported triple contrast (oral, rectal, intravenous) CT had 97% sensitivity, 98% specificity and 98% accuracy in detection of PAT with subsequent reduction in negative laparotomy rate.(10) A more recent study of the use of single contrast (intravenous) CT for PAT determined CT had 98% sensitivity and 90% specificity for predicting need for laparotomy.(11) A meta-analysis in 2009 also confirmed CT as an effective imaging study in the triage of PAT patients to the operating room.(12) Laparoscopy, as an alternative to laparotomy, has also been extensively evaluated for this indication. Sosa and colleagues have reported success with diagnostic laparoscopy in reducing the number of negative laparotomies and subsequent complications.(13)
With the assumption peritoneal violation has occurred, intravenous antibiotics should be administered to all patients presenting with PAT as soon as feasible. Broad-spectrum coverage for gram-positive, gram-negative and anaerobic organisms is the goal. At our institution, we routinely administer ceftriaxone (Rocephin®) and metronidazole (Flagyl®) if the patient is not allergic to these antibiotics. It is interesting to note there have been no randomized controlled trials to either support or refute the use of prophylactic antibiotics in PAT.(14) If time permits, tetanus immunization history should be queried and updated. For the stable patient being treated at a trauma center, further testing under the guidance of the on-call trauma surgeon such as local exploration, CT or laparoscopy may be done. If serious injuries are identified or the patient becomes unstable, laparotomy may be performed to control any hemorrhage, halt contamination, identify all injuries, and proceed to definitive repair or damage control. Disposition of patients with PAT should be ultimately at the discretion of the surgeon.
Outcome: Abdominal CT demonstrated the bullet had lodged near the liver but no operable injury was detected. The patient was discharged two days later.
Delay in transfer for imaging studies such as CT should be avoided.
Although PAT is a frequent occurrence in inner city trauma centers, all emergency physicians should be prepared to care for these patients whether they work in an urban, suburban or rural ED. Rapid assessment, intervention and triage are essential. As the patient is transferred from the EMS responders to the ED, the emergency physician should get a quick history from paramedics. Abnormal prehospital vital signs and any deterioration en route should be documented. As usual, airway, breathing, circulation, disability and exposure (ABCDEs) are part of the primary survey. If the patient is unresponsive or has waning mental status, intubation should be performed. Large bore intravenous access should be established, and crystalloid such as normal saline infused to maintain systolic pressure >90 mm Hg.
The concept of "permissive hypotension," in which the amount of crystalloid is titrated to systolic blood pressure of 90 mm Hg to prevent dilution of clotting factors, makes teleological sense.(15) There is new evidence that large volumes of crystalloid may have significant noncolligative and even inflammatory side effects.(16) Patients presenting with hypotension are assumed to have lost 30-40% of their blood volume (Class III shock) and should receive blood products as soon as possible. If time is an issue, non-crossmatched products should be given. Secondary survey should follow once vital signs have stabilized, with head to toe exam to detect occult injuries.
These patients may have also sustained blunt trauma to the head and torso. All entrance wounds should be marked prior to x-ray imaging. If possible, obtaining information from the patient, police or paramedics regarding the details of the incident such as number of shots fired, identification of assailant, type of weapon used and sites of pain is important. Indications for immediate laparotomy include hemodynamic instability, evisceration, peritonitis, impaled object, blood from natural orifices, high-velocity missile injury and unreliable exam. With regard to imaging, at the very minimum a portable chest x-ray should be obtained on all patients presenting with PAT to determine if hemo/pneumothorax is present, and if the missile has lodged in the thorax. If such an injury is detected, the emergency physician should proceed with chest tube placement.
For the emergency physician working in a non-trauma center or hospital without a surgeon willing to accept care, a critical task becomes arranging transfer of the patient to a trauma center. This requires contacting a trauma surgeon who will accept the patient and an EMS service that will expeditiously transport the patient. This is often via air ambulance. Steps to anticipate adverse events en route should be undertaken. These may include provision of blood products, securing a chest tube for those patients with hemo/pneumothorax and intubation if the patient might become unresponsive or combative en route. Delay in transfer for imaging studies such as CT should be avoided, since definitive treatment cannot be provided no matter what the findings are. Diagnostic peritoneal lavage is rarely performed by emergency physicians anymore, as it is time-consuming, invasive and provides no information about the anatomical location of the putative injury.
Outcome: Portable chest x-ray demonstrated a left hemothorax with the bullet lodged in the thoracic cavity. A chest tube was placed, and the patient received four units of crossmatched packed red blood cells – two in the ED and two en route during transfer. Air ambulance transported him to the accepting trauma center, where he underwent operative repair of diaphragm, spleen and colon injuries.
Trace pelvic free fluid in non-trauma female patients of reproductive age is considered normal.
Focused assessment with sonography for trauma (FAST) for the triage of unstable BAT patients to laparotomy has become standard of care. The use of FAST for PAT detection has not been as extensively studied as for BAT. It is useful for detecting hemopericardium, hemoperitoneum and, in experienced hands, hemo/pneumothorax. Sensitivity of FAST in this setting has been reported to be 46-67%, with specificity of 94-98%.(18) Thus, stable patients with positive FAST will most likely undergo CT imaging, and unstable patients will go directly to the operating room regardless of FAST findings. The pericardial view has been shown to be of particular importance in PAT patients presenting in pulseless electrical activity.(19)
Trace pelvic free fluid in non-trauma female patients of reproductive age is considered a normal physiological finding by radiologists. This fluid results from progression of the normal menstrual cycle, including ruptured ovarian follicles, ovarian exudation and retrograde menstruation. In the setting of trauma, pelvic free fluid cannot be dismissed as normal. In two BAT studies, the finding of any free fluid in women of reproductive age was associated with a higher incidence of intra-abdominal injury.(20)(21)
Outcome: The patient was transferred without incident. She underwent laparotomy the following day after developing increasing abdominal pain and fever, and she was found to have a small bowel injury.
Perform thoracotomy without delay, as it represents the patient's best chance for survival.
Thoracotomy currently remains an important ED procedure, as it enables relief of cardiac tamponade, control of cardiac bleeding, compression of the proximal aorta and provision of open cardiac massage. Patients should be considered for thoracotomy if they had measurable vital signs on arrival or en route prior to their cardiopulmonary arrest. Branney and associates reported GSW to the abdomen was among the mechanisms of injury associated with the highest survival rate (13%) after ED thoracotomy.(22) Edens and co-workers recently reported a survival rate of 17% in PAT patients during their experience at a combat surgical hospital in Iraq.(23) Emergency physicians should be prepared to perform thoracotomy without delay in this situation, as it represents the patient's best chance for survival.
Outcome: Intubation and a left thoracotomy were immediately performed by the emergency physician. No injury to the heart was identified. Two liters of normal saline and 2 units of non-crossmatched blood was rapidly infused. Manual compression of the proximal aorta resulted in return of pulse and measurable blood pressure. The patient was taken to the operating room where abdominal aortic injury was identified and repaired successfully. The patient was discharged from the hospital with normal neurological function.
Knives create different patterns of abdominal injury such as a stab or slash wounds. Sharp objects resembling knives such as wood sticks, metal poles, arrows, create these injuries as well. The site of the wound has implications for injury potential. Selective non-operative management of anterior abdominal SWs is standard of care in the United States today. Approximately half of these injuries may be managed without surgery. Cothren et al. reported local wound exploration was an important diagnostic modality in the treatment of anterior abdominal SWs.(24) Only 11% of these patients required surgery, and 46 of 139 patients were discharged immediately from the ED based solely on a negative local exploration. Unless the treating emergency physician is experienced and comfortable with this technique, it is best left to the trauma surgeon to perform and decide the patient's disposition.
Ultrasound to detect fascial violation has been studied with sensitivity of 59% and specificity of 100%.(25) The authors concluded that a positive finding precludes local wound exploration but a negative finding cannot be relied upon. Posterior abdominal SWs may have significant associated injuries such as bowel perforation, renal and ureteral injury, and vascular injury. Local wound exploration may be less accurate for these patients, and CT imaging represents a preferred alternative. For impalement injuries, the object should be left in place with the assumption it is tamponading a vascular injury.
Intoxicated patients with life-threatening injuries should not be allowed to leave the ED.
Intoxicated patients with life-threatening injuries should not be allowed to leave the ED. The emergency physician should request all readily available personnel, including nurses, technicians, janitors, security and/or law enforcement, to assist in physical restraint. If there are not enough team members to safely restrain the patient, he should be allowed to leave, and law enforcement notified immediately so that he can be arrested and brought back to the ED. Chemical restraint with intravenous benzodiazepines and antipsychotics should be administered if the patient is combative. These patients do not have the capacity to understand the gravity of their injuries, thus providing the treating physician with medico-legal protection. If chemical restraint fails, it may be necessary to perform rapid sequence induction and intubation to achieve ultimate control of the situation. This is especially important during air transport, as a combative patient could result in a crash of the plane or helicopter.
Outcome: The patient attempted to punch the emergency physician as he approached with the Q-tip. He was then physically restrained with the aid of two nurses, one radiology technician, a security guard and a janitor. He received intravenous haloperidol and diazepam. After successful sedation, he was taken to the operating room after local wound exploration revealed violation of the peritoneum, and bowel and liver injuries were identified and repaired. He later sued the emergency physician, trauma surgeon and hospital for battery and false imprisonment. The lawsuit was unsuccessful, as it did not progress past the discovery phase.
Penetrating injuries to the abdomen may result from several mechanisms. Firearms and sharp objects such as knives are often used in criminal assaults or self-inflicted incidents. Blast injuries with penetrating wounds from shrapnel are most likely encountered on the battlefield but may occur as a result of terrorist attacks or occupational accidents. Firearms such as rifles, handguns, shotguns and BB/pellet guns have significant differences in injury patterns from their ballistic properties. It is estimated that there are over 30,000 fatal and 100,000 non-fatal gunshot injuries per year in the United States. Stab wounds are encountered three times more often than gunshots but have lower transmitted energy, thus lower mortality.
Many factors determine the extent of intra-abdominal injury from a bullet. The type of gun used, type of bullet, distance of the victim from the gun, location and trajectory of the bullet, and permanent versus temporary cavity produced from the injury. A permanent cavity results from a crush-type injury, and a temporary cavity results from a blast effect with stretching of tissue. Bullet types include full metal jacket, lead, soft-point, semi-jacketed, hollow-point and ballistic-tipped.
The most severe injuries occur with fragmentation of the bullet.
The most severe injuries occur with fragmentation of the bullet. The potential for injury was recognized by the various armies of the world when the Hague Convention of 1899 banned the use of expanding and/or fragmenting bullets in future wars. Not all countries, criminals or terrorist organizations have followed this dictum, however.
The .22 round is a commonly used bullet that is cheap and readily available. It is a low-energy round. Shotgun injuries at close range are considered high-energy with potential for tremendous tissue damage. The AK-47 fires a high-energy 7.62x39 mm cartridge, which has the potential for significant wounding from fragmentation due to yaw, essentially a zigzag, tumbling type of motion. However, high-energy projectiles may produce relatively minor wounds in cases where the projectile enters and exits the body before beginning to yaw.(26) Primary injury from blasts occurs from the shock wave followed by a secondary injury from shrapnel. Emergency physicians treating these patients should also consider potential tertiary injuries from falls, collisions, smoke inhalation, and burns.
Recombinant activated factor VIIa (NovoSeven®) is a vitamin K-dependent glycoprotein that is structurally similar to the human form. It is approved for the treatment of bleeding episodes in patients with hemophilia A or B who have developed inhibitors to factor VIII or factor IX, respectively. It promotes hemostasis by activating the coagulation cascade. Clinical trials in the setting of BAT and PAT have not shown that the use of factor VIIa results in significantly improved survival rates but it does result in fewer transfusions of blood products and later complications such as acute respiratory distress syndrome (ARDS).(27)(28) A recent study from the Iraq conflict also supports the findings of these earlier trials.(29) At this time there is no definitive reason to use factor VIIa for PAT patients in the initial resuscitation, as it is usually difficult to obtain and extremely expensive. However, if the patient requires significant transport time or there is a shortage of blood products, use of factor VIIa may be advantageous if the emergency physician can actually obtain it expeditiously.
Outcome: Portable chest x-ray demonstrated bilateral hemo/pneumothoraces with shrapnel in the thoracic cavity, and chest tubes were placed immediately. The patient became hemodynamically unstable and was taken to the operating room where injuries to her spleen, kidney, bowel and diaphragm were identified and repaired. Request for factor VIIa was made to the pharmacy, and this was given in the operating room. A CT scan of the head after surgery identified a temporal bone skull fracture and subdural hemorrhage which required a separate operation. After several weeks she was eventually discharged neurologically intact.