eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Abdominal Trauma, Penetrating

Author: Paul A Testa, MD, Resident, Department of Emergency Medicine, New York University Medical Center, Bellevue Hospital
Coauthor(s): Eric Legome, MD, Chair, Department of Emergency Medicine, St Vincent's Hospital, Manhattan; Lewis J Kaplan, MD, FACS, FCCM, FCCP, Director, SICU and Surgical Critical Care Fellowship, Associate Professor, Department of Surgery, Section of Trauma, Surgical Critical Care, and Surgical Emergencies, Yale University School of Medicine
Contributor Information and Disclosures

Updated: Jul 28, 2008

Introduction

Background

During the Civil War and late 1800s, penetrating abdominal wounds were managed expectantly and were nearly uniformly fatal. Laparotomy became the treatment of choice during World War I but still with high mortality. By World War II, early laparotomy resulted in a survival rate close to 50%. The 1950s afforded availability of antimicrobials, better understanding of fluid replacement, and faster transport from the scene, which further increased survival rates. By the late 1950s, mandatory laparotomy was the rule for the management of patients with abdominal penetrating trauma. Since the 1960s, mortality rates of 9.5-12.7% for civilian gunshot wounds and as low as 3.6% for stab wounds have been reported in the United States.

Over this period of time, there has been a substantial evolution in patient management. Resuscitation protocols reflect the impact of appropriate crystalloid administration, the immunomodulatory properties of blood transfusions and an understanding for physiologic end points of resuscitation. Damage control surgery and treatment of abdominal compartment syndrome have had major impacts on care of the severely injured. Technologies allow less invasive and more rapid and specific diagnostic evaluations. Selective operative management and increasing application of angioembolization have served to further reduce surgical intervention. Refinement of evidence-based clinical pathways has allowed for a judicious allocation of resources.

Nevertheless, penetrating abdominal organ injury patterns and survival have plateaued over the past decade. Death from refractory hemorrhagic shock or exsanguination in the first 24 hours remains the most common cause of mortality. Damage control surgery is being used more frequently with improved early survival but with a concurrent increase in late morbidity.

Pathophysiology

Physiologic evaluation of the patient with penetrating abdominal trauma concentrates on two major findings: peritonitis and hemodynamic instability.

Peritoneal signs develop when the peritoneal envelope and the posterior aspect of the anterior abdominal wall are both inflamed. The peritoneal or retroperitoneal blood and organ contents inflame deeper nerve endings (visceral afferent pain fibers) and result in poorly defined pain. Irritation of the parietal peritoneum leads to somatic pain, which tends to be more localized; however, the diffuse nature of intra-abdominal spillage often leads to diffuse findings. The back or shoulder distribution of pain may provide a clue to the damaged organ (ie, shoulder pain from a damaged spleen with subphrenic blood).

Hemodynamically stable patients with penetrating abdominal trauma and peritonitis can be assumed to have a hollow visceral perforation and may have significant intra-abdominal hemorrhage. Thus, peritonitis on physical examination is a trigger for emergent intervention regardless of vital signs.

Hypotension, narrow pulse pressure, and tachycardia or signs of inadequate end organ perfusion in the setting of penetrating abdominal trauma provide evidence of significant intra-abdominal injury, especially vascular trauma, and warrant immediate surgical exploration. Confounding injuries or medical problems, such as tension pneumothorax or acute myocardial infarction, need be excluded.

Wounds located on the anterior abdomen can be explored locally to determine whether they penetrate the peritoneum. On the flank area and back area, exploration is more difficult and less reliable. Therefore, flank and back wounds are not explored and are considered penetrating unless obviously superficial.

Gunshot wounds, considered high-velocity projectiles, are the most common cause (64%) of penetrating abdominal trauma, followed by stab wounds (31%) and shotgun wounds (5%). Injury patterns differ depending on the weapon. Low-velocity stab wounds are generally less destructive and have a lower degree of morbidity and mortality than gunshot wounds and shotgun blasts. Gunshot wounds and other projectiles have a higher degree of energy and produce fragmentation and cavitation, resulting in greater morbidity.

The severity of shotgun wounds depends on the distance of the victim from the weapon. The mass of a bullet is minimal, and, thus, their velocity decreases rapidly when the bullet leaves the barrel of the gun. When the distance is less than 3 yd, the injury is considered high velocity, and if the distance exceeds 7 yd, most of the buckshot penetrates only the subcutaneous tissue.

In penetrating abdominal trauma due to stab wounds, the most commonly injured organs are the liver (40%), small bowel (30%), diaphragm (20%), and colon (15%). Intra-abdominal injuries from a gunshot wound are to the small bowel (50%), colon (40%), liver (30%), and abdominal vascular structures (25%).

Frequency

United States

Tracking trauma is the purview of the National Center for Injury Prevention and Control (NCICP). Data collected by this organization suggest that traumatic injury is the third overall leading cause of death and the number one cause of death in persons aged 1-44 years. Penetrating abdominal trauma affects approximately 35% of those patients admitted to urban trauma centers and 1-12% of those admitted to suburban or rural centers.

The mechanism that underlies the penetrating trauma (eg, gunshot wound, stab wound, impalement) relates to the mode of injury (eg, accidental or intentional injury, homicide, suicide). Homicide or intentional injury is the predominant mode of abdominal injury in this patient population. Accidental injury is most common in pediatric home firearm injuries but is uncommon by comparison to the overall levels of homicide and intentional injury. Suicide via penetrating abdominal trauma is uncommon.

International

The frequency of penetrating abdominal injury across the globe relates to the industrialization of developing nations, weapons available, and, significantly, to the presence of military conflicts. Therefore, frequency varies.

Mortality/Morbidity

• The death rate from penetrating abdominal trauma spans the entire spectrum (0-100%), depending on the extent of injury. Patients with violation of anterior abdominal wall fascia without peritoneal injury have a 0% mortality rate and minimal morbidity rate, while those with multiorgan injury complexes presenting with hypotension, base deficit less than -15 mEq/L HCO₃, lactate level more than 20 mmol/L, and near exsanguination have an almost 100% mortality rate.
• An average mortality rate for all patients with penetrating abdominal trauma is approximately 5% in most level 1 trauma centers, but this population is necessarily biased given the higher acuity seen at such centers, thus skewing the data.
• The most common morbidities following penetrating abdominal trauma are wound infection (2-8%) and intra-abdominal abscess with or without sepsis (10-80%, depending on presence or absence of bowel injury in combination with major vascular injury).

Race

• Race distribution in patients with penetrating abdominal trauma depends significantly on the location of the receiving hospital. Urban centers predominantly receive young African American and Hispanic males more frequently than young white males due to population demographics in these areas. A similar distribution occurs for their female counterparts.
• Although quantifying the death rate for penetrating abdominal trauma by race is difficult, the relative risk of death for penetrating injury in general is known. African American males have a 3-fold increase in relative risk of death compared with their white male counterparts. African American females have a 2.5-fold increase in relative risk of death compared with their white female counterparts. However, suburban centers tend to receive a greater proportion of youthful to middle-aged white males as their predominant patient population because of regional demographics.

Sex

Males comprise the great majority of patients with penetrating trauma injuries across the United States and the world. In some areas of the United States, approximately 90% of patients with penetrating trauma are male.

Age

Injuries are the leading cause of death in patients aged 1-44 years.

Clinical

History

The history provides clues to the most likely injury patterns and potential management priorities. Emergency medical services (EMS) personnel are often essential in providing a history, especially in a critically ill patient or someone with altered mental status.

• A common acronym is the AMPLE history:
  • Allergies
  • Medications
  • Prior illnesses and operations
  • Last meal
  • Events and environment surrounding injury
• Further historical factors include the following:
  • Anatomic location of injury and type of weapon (ie, gun, knife), which directs the diagnostic process; the number of gunshots heard, times stabbed, and position of the patient at the time of injury help describe the trajectory and path of the injuring object.
  • Close-range injuries transfer more kinetic energy than those sustained at a distance, although range is often difficult to ascertain when assessing gunshot wounds.
  • Blood loss at the scene should be quantified as accurately as possible from EMS personnel. However, previous research has shown that this assessment is very difficult and rarely reliable. The character of the bleeding (eg, arterial pumping, venous flow) may assist in determining whether major vascular injury has occurred.
  • The initial level of consciousness or, for moribund patients, the presence of any signs of life at the scene (ie, pupillary response, respiratory efforts, heart rate or tones) is vital to determine the prognosis and to guide resuscitative efforts. Particularly important is the patient's response to therapy en route to the ED. Evidence of hypotension in the field should raise suspicion for intra-abdominal injury.

Physical

The initial physical examination begins with visual assessment of the patient during transport into the ED, with particular focus on the ABCs. Rapid determinations regarding respiratory effort, perfusion, external hemorrhage, and consciousness level are usually easily made.

Initial vital signs assist in determining injury severity and need for operative intervention. Tachycardia, high or low respiratory rate, and hypotension are indicators for need for greater resource availability.

• Primary survey
  • The primary survey is defined by the mnemonic ABCDE: Airway, Breathing, Circulation, Disability, and Exposure/Environment. Although described sequentially, much of this evaluation may be performed simultaneously and problems identified are managed immediately.
    • Airway - The airway always is assessed immediately for patency, protective reflexes, foreign body, secretions, and injury.
    • Breathing - Breathing is assessed by determining the patient's respiratory rate and by subjectively quantifying the depth and effort of inspiration.
    • Circulation: The circulation assessment begins with an evaluation of the patient's mental status, skin color, and skin temperature. Patients in significant hemorrhagic shock will progress from anxiety to agitation and finally coma if their blood loss continues unabated. The traditional vital signs of heart rate, blood pressure, and respiratory rate are not sensitive or specific for hemorrhagic shock.
    • Disability: This is assessed early to document neurologic deficits before giving sedation or paralytics. The Glasgow Coma Score and the gross motor and sensory status of all 4 extremities should be determined and recorded. The physician also should recognize the need for cerebro-protection measures in cases of brain injury.
    • Exposure/environment: Exposure is particularly important in the patient with a traumatic mechanism of injury where failure to identify a second or third injury may result in major morbidity due to failure to diagnose a life-threatening injury. Complete exposure and head-to-toe visualization of the patient is mandatory in a patient with penetrating abdominal trauma. This includes buttocks, posterior part of the legs, scalp, posterior part of the neck, and perineum. There is little to be gained by practicing spinal immobilization unless spinal injury is obvious.
  • Once the primary survey is complete, a complete head-to-toe physical examination is performed as an integral part of the secondary survey, including digital rectal and genital examinations. This detailed examination may need to be delayed until after operative therapy has corrected obvious life-threatening injury.
• Secondary survey and injury assessment
  • External inspection for injuries with respect to anatomic landmarks aids identification of possible intracavitary injury. In evaluating patients with penetrating abdominal trauma, the abdomen is classically divided as follows:
    • Anterior abdomen - Anterior costal margins to inguinal creases, between the anterior axillary lines
    • Intrathoracic abdomen or thoracoabdominal area - Fourth intercostal space anteriorly (nipple) and seventh intercostal space posteriorly (scapular tip) to inferior costal margins
    • Flank - Scapular tip to iliac crest, between anterior and posterior axillary lines
    • Back - Scapular tip to iliac crest, between posterior and axillary lines
  • The physical examination is a more reliable indicator for surgical intervention with penetrating abdominal trauma than with blunt trauma. At many trauma centers, repeated abdominal examinations are the preferred approach for managing hemodynamically stable patients with penetrating abdominal stab wounds. Development of peritonitis or hemodynamic instability is an indication for operative intervention. While selective nonoperative management of penetrating abdominal trauma is practiced at most trauma centers in this country, hemodynamic instability and diffuse abdominal tenderness indicating peritonitis are surgical indications.
  • Common physical examination recommendations include evaluation for tympany (a bell-like or percussive note upon gently tapping on the abdomen), dullness to percussion, and bowel sounds. Abdominal distention, not clearly due to "bagging" or swallowed air, may be an indicator of an intra-abdominal catastrophe. A vascular injury is often found in combination with hollow or solid viscus penetration or devitalization.
  • Evisceration has historically been a clear indication for operative management. However, some centers replace eviscerated omentum and serially observe or image these patients.
  • Impaling objects may tamponade otherwise uncontrolled hemorrhage if the object resides within or crosses a major vessel or solid organ such as the portal vein or liver. Therefore, penetrative objects should not be removed except where definitive treatment can be provided.
  • Several studies have looked at ED observation and serial examination with discharge in 10-12 hours on patients with negative findings. While promising, this has not been fully validated in multiple centers.
  • Increasing pain, peritoneal findings (eg, point tenderness, involuntary guarding, rebound tenderness), or diffuse and poorly localized pain that fails to resolve also indicates that surgical exploration should be undertaken.

Causes

• Urban violence
• Domestic violence crosses all socioeconomic barriers and is an important consideration in the evaluation of injuries sustained at home and those reportedly involving the patient's family or significant other.
• Illegal drugs and legally purchased ethanol fuel all types of violence.
• Global factors - From a global perspective, penetrating abdominal trauma in most settings results principally from military actions and wars.
• Penetrating abdominal trauma may be iatrogenically introduced. A documented complication of diagnostic peritoneal lavage (DPL) is injury to the underlying bowel, bladder, or major vessels such as the aorta or vena cava. However, the incidence of such complications is relatively small.

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