Urgent considerations
See Differentials for more details
Haemorrhagic shock
The abdominal cavity is a large potential space for haemorrhage that offers little opportunity for a tamponade effect to arise due to its tendency to distend. Abdominal vascular, splenic, and hepatic injuries can rapidly result in haemodynamic instability and shock. Similarly, renal injuries can quickly haemorrhage significant volumes into the retroperitoneal space. It is therefore critical that initial evaluation and management are carried out in a timely manner.
Haemorrhagic shock is a condition of reduced perfusion with inadequate oxygen delivery caused by acute blood loss. It may present with hypotension; tachycardia; oliguria; tachypnoea; diminished or absent pulses; altered sensorium; and pale, cold, clammy skin. Urgent consultation with a surgeon and anaesthetist is advisable. Patients in haemorrhagic shock require aggressive fluid resuscitation, blood transfusions, and control of the haemorrhage. Patients who are haemodynamically unstable or who have diffuse abdominal tenderness after penetrating abdominal trauma should be taken urgently for laparotomy.[13]
European guidelines recommend that patients should undergo an immediate bleeding control procedure if they have an obvious source of bleeding, and if they present with haemorrhagic shock in extremis and have a suspected source of bleeding.[14] Patients with gunshot wounds, major stab wounds, or shrapnel wounds are examples of patients who typically fall into this category. Blood should be drawn for crossmatch and multiple units of packed red blood cells prepared in anticipation of a transfusion.
Patients with profound haemorrhagic shock, suggested by extreme hypotension and a severely reduced mental status (i.e., coma), require an immediate un-crossmatched blood transfusion. Pressure delivery and blood-warming devices can be helpful in situations of profound haemorrhage. With large-volume transfusions, coagulation may be affected and this needs to be monitored and treated with fresh frozen plasma and platelets as necessary. These patients require at least two functioning large-bore peripheral intravenous lines for fluid administration and a Foley's catheter to allow accurate monitoring of urine output. If peripheral lines are difficult to place, a short, large-calibre femoral or subclavian central line is recommended. Long double- or triple-lumen central lines should be avoided as fluid cannot be infused rapidly through these catheters.
A 2009 study found that aggressive transfusion of packed red blood cells, fresh frozen plasma, and platelets improves the outcome in haemodynamically unstable trauma patients.[15] Evidence from a small, randomised trial suggests that coagulation factor concentrates may be more effective than fresh frozen plasma in patients with trauma-induced coagulopathy.[16]
Delays in the amount of time prior to laparotomy in an abdominal trauma patient with intra-abdominal bleeding increase morbidity and mortality.[17] European guidelines recommend serum lactate testing to estimate and monitor the extent of bleeding and tissue hypoperfusion.[14] Base-deficit, calculated from arterial blood gas measurement, may be used as an alternative; however, lactate levels more specifically reflect the degree of tissue hypoperfusion.[14]
Antifibrinolytics (such as tranexamic acid) should be considered in all trauma patients with acute severe haemorrhage as soon as possible, as they have been shown to increase survival when given within 3 hours of injury.[18][19] A meta-analysis found that among patients with traumatic bleeding or postnatal haemorrhage, immediate treatment with tranexamic acid greatly increased the odds of survival, with the survival benefit decreasing by about 10% for every 15 minutes of treatment delay until 3 hours, after which there was no benefit.[20]
Guidelines recommend that patients presenting with haemorrhagic shock and an unidentified source of bleeding (as may occur with blunt trauma) undergo immediate further assessment by a focused assessment by sonography in trauma (FAST) examination.[21][22] This test is useful to quickly diagnose intra-abdominal haemorrhage.[23][24] The FAST examination uses a bedside ultrasound to provide images of the right upper quadrant, left upper quadrant, and pelvis to assess for intra-abdominal haemorrhage. According to one Cochrane review, the sensitivity and specificity of point of care sonography is 68% and 95% for adults and children with abdominal trauma.[25] If a FAST examination is unavailable or unreliable, a diagnostic peritoneal lavage (DPL) may be performed to assess for intraperitoneal bleeding.[26] DPL involves making a small midline incision below the umbilicus and using a needle and small catheter to aspirate intraperitoneal fluid to assess for blood or bile. If the aspirate is found to contain 10 mL of gross blood or bile, an exploratory laparotomy is indicated. In the absence of gross blood or bile, DPL requires 1 litre of fluid to be infused into the peritoneum and then drained. The effluent should be sent to the laboratory and evaluated. Laboratory criteria for a positive DPL are:
>1.0 × 10¹² red blood cells/L (>100,000 red blood cells/mm³)
>0.50 × 10⁹ white blood cells/L (>500 white blood cells/mm³)
Presence of bacteria, bile, or food particles.
Patients found to have significant free intra-abdominal fluid according to FAST examination (or DPL) and haemodynamic instability should undergo urgent surgery.
European guidelines recommend using contrast-enhanced whole-body CT (WBCT) to detect and identify the type of injury and the potential source of bleeding.[14] Usually, patients with penetrating trauma and signs of haemodynamic instability undergo surgery without CT; however, some authors recommend WBCT while continuing resuscitation, regardless of haemodynamic status.[22][27][28][29]
The Eastern Association for the Surgery of Trauma makes the following recommendations with regard to managing penetrating abdominal trauma.[13]
Take patients who are haemodynamically unstable or who have diffuse abdominal tenderness for urgent laparotomy
Perform exploratory laparotomy or further diagnostic investigation for intraperitoneal injury in patients who are haemodynamically stable but have an unreliable clinical exam (e.g., patients with severe head injury, spinal cord injury, severe intoxication, or need for sedation or anaesthesia)
Routine laparotomy is not indicated in haemodynamically stable patients with:
Abdominal stab wounds without signs of peritonitis or diffuse abdominal tenderness (away from the wound site) in centres with surgical expertise
Abdominal gunshot wounds if the wounds are tangential and there are no peritoneal signs
Penetrating injury isolated to the right upper quadrant with stable vital signs, reliable examination, and minimal to no abdominal tenderness.
Consider abdomino-pelvic CT in patients who are initially managed non-operatively
Diaphragmatic lacerations and peritoneal penetration may be evaluated with diagnostic laparoscopy
Serial physical exams can reliably detect significant injuries if performed by experienced clinicians and the same team
Most patients managed non-operatively can be discharged after 24 hours of observation if the abdominal exam is reliable and they have minimal or no abdominal tenderness.
Missed or delayed diagnosis of intra-abdominal organ injury
Injuries to the spleen, liver, and abdominal vasculature
Significant intra-abdominal haemorrhage and haemodynamic instability may result from abdominal vascular, splenic, and hepatic injuries. A FAST examination and abdominal CT scan with contrast have important roles in diagnosing these injuries and should be initiated promptly when these injuries are suspected.
Pancreatic injury
Diagnosis of pancreatic injuries is notoriously difficult due to the retroperitoneal location of the pancreas, resulting in delay in the development of signs and symptoms. Vague abdominal pain radiating to the back and abdominal tenderness usually do not appear until some hours after the traumatic event. An abdominal CT scan is key to making the diagnosis, as serum amylase and serum lipase may only later become elevated. Magnetic resonance cholangiopancreatography is recommended to definitively exclude pancreatic parenchymal and ductal injuries.[8]
Diaphragmatic injury
Missed diaphragmatic injuries are associated with significant morbidity from herniation and strangulation of abdominal viscera. There is a high incidence of diaphragmatic injury in thoraco-abdominal penetrating trauma and blunt abdominal trauma. The patient may complain of chest pain, abdominal pain, or shortness of breath. There may be haemodynamic instability when the patient lies supine. Typically, there are diminished breath sounds on the affected side, with bowel sounds audible over what would normally be the lung fields. Thoraco-abdominal CT is good for diagnosing diaphragmatic injuries related to blunt trauma, but laparoscopy is better for detecting diaphragmatic injuries relating to penetrating trauma.
Stomach and small bowel injuries
Significant morbidity and mortality accompany a missed or delayed diagnosis of small bowel injury. Patients often do not have signs of peritonitis in the early period and small bowel injury may be missed. This may happen in the context of blunt abdominal trauma, where a small bowel injury is not suspected, or when a stab wound to the anterior abdomen is misdiagnosed as not having penetrated the posterior abdominal fascia. Stomach injury often results in a rapid onset of burning epigastric pain, followed by rigidity and rebound sensitivity. Classically, free air under the diaphragm is seen on erect chest x-ray with perforation of a hollow viscus, although this is not always seen and diagnosis may also require abdominal CT and DPL, along with careful evaluation of the clinical and laboratory findings.
Mesenteric injury
There is a high rate of delayed diagnosis of mesenteric injury after blunt abdominal trauma, as patients may be initially asymptomatic and CT scanning has a high false-negative rate. Delayed diagnosis can result in bowel ischaemia. Maintaining a high level of clinical suspicion, along with FAST examination and abdominal CT, is important in ensuring that the diagnosis is not missed.
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