A 22-year-old man presents to the hospital 1 hour after sustaining two stab wounds during an altercation. On examination, the patient appears intoxicated and grimaces during manipulation of the wounds. His temperature is 36.8°C (98.2°F), pulse rate 86 beats/min, blood pressure 128/80 mm Hg, and respiratory rate 22 breaths/min. A thorough physical examination reveals two stab wounds. One wound is located at the anterior axillary line, 1 cm above the left costal margin; the second wound is located 4 cm left of the umbilicus. There is no active bleeding from either wound site. The breath sounds are present and equal bilaterally. The abdomen is tender only in the vicinity of the injuries. The patient claims that the knife used in the attack was approximately 5 in (12.7 cm) in length.
What is your next step?
What are the potential injuries?
ANSWERS TO CASE 15: Penetrating Abdominal Trauma
Summary: A 22-year-old hemodynamically stable, intoxicated man presents with stab wounds to the left thoracoabdominal region and abdomen.
• Next step: Perform primary and secondary assessments focusing on the abdominal examination and obtain an upright chest radiograph (to assess for pneumothorax, hemothorax, and free intra-abdominal air).
• Potential injuries: Heart, lung, diaphragm, intra-abdominal injury.
1. Learn the various possible approaches in the selective treatment of patients with a penetrating abdominal injury.
2. Learn the benefits and potential limitations associated with the various diagnostic strategies for detecting intra-abdominal injuries.
3. Learn the evolving strategies to the initial management of hypotensive penetrating abdominal injury patients.
This patient has sustained penetrating thoracoabdominal and abdominal injuries. Initial attention should be directed to the primary survey, which includes assessment of the airway, breathing, and circulation (ABCs). These appear to be stable based on the scenario. For this patient, the concerns include possible injury to the thoracic structures, diaphragm, and intra-abdominal structures. There are a number of different acceptable management options, but a reasonable approach for this patient may include an initial upright chest radiograph to rule out pneumothorax, hemothorax, and free air, with a study repeated in 6 hours if no abnormalities are seen initially. Subsequently, a focused abdominal sonography for trauma (FAST) examination can be performed to exclude pericardial effusion, which would indicate a cardiac injury. The patient could undergo diagnostic laparoscopy to determine if there is peritoneal penetration of the stab wounds and if there is a diaphragm injury. Any suspicion of a hollow viscus injury during laparoscopy should result in a celiotomy. Alternatively, a CT scan can be obtained initially to help determine the depth of knife penetration. If the CT scan is able to identify a knife tract that does not violate the peritoneal cavity or penetration near the diaphragm, he may be simply observed or discharged.
APPROACH TO: Penetrating Abdominal Trauma
Patient treatment always begins with an evaluation and management of ABCs—a primary survey. Listening to the patient allows the examiner to determine the adequacy of the airway and brain perfusion, and to make certain there are no obvious neurologic deficits. Breathing is evaluated by listening to the patient’s breath sounds. The finding of obvious decreased breath sounds on the left side is an indication for the placement of a chest tube. In addition to measuring vital signs, the examiner can evaluate the circulation by palpating the skin and observing the capillary refill. Cool skin or a capillary refill for more than 2 seconds is an indication of shock. The circulation evaluation includes an examination for distended neck veins or muffled heart tones, which are indications of cardiac tamponade and require immediate treatment.
A determination of the extent of disability is the equivalent of a rapid neurologic examination, and it includes assessing the pupillary response as well as the patient’s response to verbal stimuli. The patient’s clothes should be removed to look for evidence of other injuries. During the primary survey, an upright chest radiograph should be obtained. This chest radiograph is useful in the evaluation of pneumothorax or hemothorax, the cardiac silhouette for evidence of cardiac injury, and intra-abdominal free air consistent with a hollow viscus injury. If the chest radiograph shows no abnormalities, it should be repeated at 4 to 6 hours to rule out a delayed pneumothorax. FAST should also be performed to rule out blood in the pericardium. The sensitivity of FAST in detecting pericardial blood is as high as 100%, but its sensitivity in detecting abdominal injury approximates only 50%. Therefore the use of FAST in penetrating trauma is still controversial.
There have been significant paradigm shifts in the approach to the initial management of hypotensive trauma patients, with many of the strategies having been developed based on observations from the management of combat casualties during the ongoing military activities in Iraq and Afghanistan. The principles guiding these changes are that the majority of hypotensive trauma patients have ongoing bleeding and the approach to initial resuscitation should be directed to minimize their bleeding rather than restoring normal vital signs. This approach has been referred to as hemostatic or damage-control resuscitation. The hypotensive trauma patient without evidence of brain injuries is purposefully kept hypotensive at systolic blood pressures in the 80s to 90s. Crystalloid resuscitation is minimized on the basis that excess crystalloid infusion would contribute to decrease in hematocrit, body temperature, and dilution of clotting factors. Therefore blood products are used to resuscitate the patient as needed, and the blood products are provided at a ratio of 1:1:1 (packed RBC: fresh frozen plasma: single donor platelet). Although this approach is increasing accepted as the standard approach for critically injured patients in many centers, the strategy has not been validated by randomized controlled studies.
Following the primary survey, a careful secondary survey should be performed to ascertain the extent of the patient’s injuries. The most important part of the secondary survey in this patient is the abdominal examination. The presence of prominent physical findings such as rigidity, guarding, or significant tenderness distant from the stab wounds is an indication for celiotomy. It is important to note that the physical examination may not be reliable in patients with penetrating abdominal trauma, especially in those who are intoxicated.
Patients with penetrating abdominal trauma have historically undergone mandatory surgical exploration, resulting in a high nontherapeutic celiotomy rate and a high complication rate. The practice of selective celiotomy currently has become widely accepted. This change in practice has resulted in alternative methods of evaluation, including admission to the hospital for serial abdominal examinations, local exploration of the wound followed by diagnostic peritoneal lavage (DPL), and abdominal computed tomography (CT) or exploratory laparoscopy.
Observation of asymptomatic patients with abdominal stab wounds for the development of positive physical findings results in a low nontherapeutic celiotomy rate. Patients who are observed require frequent evaluations for peritoneal findings or hemodynamic instability. Most studies have reported that abdominal injuries manifest in the vast majority of patients within the first 24 hours; therefore patients should be observed for a minimum of 24 hours. A policy of observing patients with stab wounds is associated with the reduction in nontherapeutic laparotomy; however, this approach could result in delays in treatment of injuries and compromised patient outcomes.
Local wound exploration of stab wounds permits a determination of fascial penetration. A sterile field is prepared around the stab wound, and the area is infiltrated with a local anesthetic. The stab wound is enlarged to permit adequate exploration, and the tract of the wound is followed. If the anterior abdominal fascia has been penetrated, further evaluation is indicated.
Diagnostic peritoneal lavage (DPL) was designed to sample the intra-abdominal contents for blood, inflammation (white blood cell [WBC] count), or fecal matter. A catheter is placed in the abdomen using the Seldinger (catheter over a guidewire) technique. The catheter is aspirated after placement to look for evidence of gross blood or fecal contents. If the aspiration results are negative, 1 L of warmed normal saline is instilled into the abdomen and then removed by gravity. The criteria for a positive DPL results in patients with blunt trauma are well established and include gross aspiration of 10 mL of blood, aspiration of fecal contents, or the presence of greater than 100,000/mm3 red blood cells (RBCs) or 500/mm3 WBCs in the lavage fluid.
Diagnostic Peritoneal Lavage Criteria
Although the criteria for grossly positive DPL results and the WBC count criteria (500 cells/mm3) for penetrating are the same as for blunt trauma, the RBC count criteria have not been standardized. The published thresholds range from 1000/mm3 to 100,000/mm3. The use of low RBC count criteria results in sensitivities approaching 100% but in nontherapeutic celiotomy rates as high as 30%. The use of higher erythrocyte thresholds is associated with a reduced sensitivity and a reduced nontherapeutic celiotomy rate. DPL is not a sensitive test for injuries to the diaphragm or retroperitoneal structures. Over the last decade, the application of DPL has become more limited, as FAST and CT scans have become more accessible.
Computed tomography (CT) is being increasingly applied for the evaluation of penetrating torso injuries in hemodynamically normal patients. Oral, intravenous, and rectal contrasts are often used to help detect intraperitoneal fluid and enteric content leakage. Results from a CT scan are considered positive if there is evidence of peritoneal penetration, free intraperitoneal fluid or air, intraperitoneal extravasation of contrast material, or penetration tract near an intraperitoneal hollow organ. Abdominal CT imaging can be used to follow a stab wound tract or bullet path accurately, allowing determination of the structures that are at risk for injury. Some solid-organ injuries can be managed nonoperatively if a hollow viscus injury can be ruled out and the patient remains stable. CT scanning is noninvasive and specific for injury, but it is not sensitive in detecting diaphragm injuries.
Diagnostic laparoscopy is also an option in assessing patients with penetrating abdominal trauma. It is extremely useful in evaluating peritoneal penetration, solid-organ injury, and diaphragm injury. Laparoscopy is not sensitive in detecting hollow viscus injury. Laparoscopy is unique in that it is accurate in the detection of diaphragm injuries and injuries that can be repaired using laparoscopic techniques. Laparoscopy obviates the need for a full celiotomy in approximately 50% of stable patients with abdominal stab wounds. The disadvantages of laparoscopy are its lack of sensitivity in detecting hollow viscus injuries and the requirement for an operative procedure.
15.1 A 25-year-old man sustains a stab wound to the abdomen 8 cm superior to the umbilicus. His skin is cool, and he is diaphoretic. His blood pressure is 74/40 mm Hg, and his pulse is 130 beats/min. His abdomen is distended and diffusely tender. Which of the following management possibilities is most appropriate?
A. Abdominal CT scan
B. Diagnostic peritoneal lavage
E. Local wound exploration
15.2 A 47-year-old man sustains a stab wound to the left upper quadrant of his abdomen. He complains of minimal pain. He is alert and hemodynamically normal, and the results from his abdominal examination show no abnormalities. Which of the following statements is true?
A. Abdominal CT is sensitive in the detection of diaphragm injuries.
B. The FAST examination reliably rules out intra-abdominal injury.
C. Local wound exploration revealing fascial penetration is an absolute indication for celiotomy.
D. Intra-abdominal injury is highly unlikely in this patient.
E. The patient should be admitted for a 24-hour observation period.
15.3 A 37-year-old woman sustains a stab wound located at the anterior axillary line, 3 cm superior to the costal margin. She is alert and has normal mentation. Her blood pressure is 104/60 mm Hg, and pulse is 100 beats/min. Which of the following is the most appropriate next step?
A. Listen to the patient’s breath sounds.
B. Obtain a chest radiograph.
C. Perform a FAST examination.
D. Examine her abdomen.
E. Perform a CT scan of the abdomen and chest.
15.4 A 56-year-old man was stabbed in the right lower quadrant of his abdomen. He complains of pain at the wound site. His vital signs are normal, and the findings from his abdominal examination are normal. Local wound exploration reveals penetration of the anterior fascia, and DPL reveals 7000 RBCs/mm3 and 750 WBCs/mm3. Which of the following is the most appropriate next step?
A. Repeat the DPL in 4 hours.
B. Obtain an abdominal CT scan.
C. Perform a laparoscopy.
D. Continue with observation and non-operative treatment.
E. Perform a celiotomy.
15.1 D. The patient tachycardia and hypotension suggest that he has a life-threatening intra-abdominal hemorrhage, and after the ABCs and volume resuscitation he needs immediate celiotomy. Based on the location of the patient’s stab wound, it is also conceivable that his clinical picture could be due to a cardiac injury and cardiac tamponade; therefore preparations should also be made to address that possibility. CT scan, wound exploration, diagnostic peritoneal lavage, and laparoscopy are diagnostic techniques to determine if significant intraperitoneal injuries had occurred, and these modalities are inappropriate for a patient exhibiting clinical signs of intra-abdominal injury.
15.2 E. Asymptomatic stab wounds can be observed for the development of abdominal symptoms or hemodynamic instability. The sensitivity of the FAST examination is only 50%. The initial abdominal examinations may be relatively normal in patients with significant intra-abdominal injuries; for example, perforation of the colon with fecal contamination would not produce peritoneal irritation until peritonitis develops after many hours.
15.3 A. The primary survey (ABCs) should be performed first. Rather than focusing on radiological studies or abdominal examination, the first priority should be assessing airway and breathing (air exchange). Chest x-ray and CT scan of the chest are not inappropriate diagnostic studies for this patient with thoracoabdominal penetrating injury, but auscultation takes precedence over the imaging studies. The FAST is not as helpful in this patient; as FAST has low sensitivity in patients who are hemodynamically stable, failure to identify free fluid in the abdomen does not rule out intra-abdominal injuries.
15.4 E. The DPL results are positive by WBC criteria, and hollow viscus injury is suspected. Celiotomy is the best method of excluding this type of injury.
The sensitivity of the FAST examination in detecting pericardial blood is as high as 100%, but its sensitivity in detecting abdominal injury approximates 50%.
An abdominal examination revealing prominent findings such as rigidity, guarding, or significant tenderness distant from the stab wounds is an indication for celiotomy.
Selected patients who have sustained penetrating abdominal injury may be observed for a minimum of 24 hours.
If the anterior abdominal fascia is penetrated by a wound, further evaluation is needed.
Positive DPL results in blunt trauma patients include gross aspiration of 10 mL of blood, aspiration of fecal contents, or the presence of greater than 100,000 RBCs/mm3 or 500 WBCs/mm3 in the lavage fluid.
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