The abdomen is one of the five sites of life-threatening haemorrhage in the trauma patient and should be assessed as part of the circulatory assessment in the primary survey.
The boundaries of the abdomen are from the nipples at full expiration to the inguinal ligaments and pubic symphysis anteriorly, and the tips of the scapula to the gluteal skin crease posteriorly. Remember that lower chest trauma may cause abdominal injury.
The abdomen is divided into the:
• Peritoneal cavity (including liver, spleen, stomach, parts of duodenum and bowel).
• The retroperitoneum (including major vessels, kidneys, ureters, colon).
• The pelvic cavity (including bladder, rectum, iliac vessels, and internal genitalia in females).
Diagnosis of an abdominal injury is very difficult particularly in a multiple injury patient who may have reduced conscious level or distracting injury. Missed injury is associated with a poor outcome.
Mechanism of injury
• Blunt (see Blunt abdominal trauma, [link]).
• Penetrating (see Penetrating abdominal trauma, [link]).
• Blast injury (see Blast injury, [link]).
It is important to take a detailed history from the patient, paramedic, or police regarding the mechanism of injury to assess the likelihood of abdominal injury.
Signs, symptoms, and clinical findings
• Abdominal pain.
• pattern bruising, e.g. seat belt sign;
• wounds to anterior or posterior abdomen;
• distension (late sign).
• Abdominal tenderness on palpation or peritonism.
• Auscultation for bowel sounds (may be difficult in Resuscitation room and not a reliable sign).
• Rectal or vaginal bleeding – PR for rectal integrity and tone.
• Tachycardia and/or hypotension.
Beware significant amounts of blood may be present in the abdominal cavity without any clinical signs.
• Bloods: may be normal despite significant injury.
• Plain abdominal X-ray: is rarely useful and an erect CXR to assess for free gas is generally not possible in a trauma patient.
• Urinalysis: for blood on dipstick and a pregnancy test in all women of child-bearing age. A catheter may be required to obtain a urine sample.
• FAST USS (see Investigation of abdominal injury, [link]).
• CT scan (see Investigation of abdominal injury, [link]).
Initial management of abdominal injury
• Treat airway and breathing problems.
• Oxygen 15 L.
• Insert 2 × wide bore IV access.
• Send bloods for FBC, U&E, LFT, amylase, clotting and X match.
• Give IV sodium chloride 0.9% in 250 mL boluses to maintain SBP above 90 mmHg.
• Involve a surgeon at an early stage.
• Inform the duty anaesthetist and theatres if the patient is likely to require an early laparotomy.
• Consider the need for a NGT to decompress the stomach and reduce risk of vomiting.
• Insert a urinary catheter and monitor hourly urine output. This should not be performed before urological input if there are any signs of urethral injury, e.g. blood at meatus, scrotal, or perineal haematoma, significant pelvic fracture and patient unable to self-void.
Log-rolling a patient with intra-abdominal injury may lead to disruption of clots and catastrophic internal haemorrhage with shock. Try to minimize movements using a scoop stretcher or pat slide.
A compromise may have to be met to thoroughly assess the back and flanks for posterior abdominal injury and rectal examination. Depending on the mechanism of injury, this may include a gloved hand passed under the patient to check for bleeding or wounds, or a limited 15° log roll each side to directly visualize the back.
Focused assessment with sonography for trauma ultrasound scan
FAST is used for the rapid assessment of free fluid in the abdominal cavity or the pericardium as an adjunct to the primary survey.
• Rapid, non-invasive bedside test.
• Can be performed in the Resuscitation room by a trained emergency medicine or surgical doctor on haemodynamically unstable patients.
• Easily repeated.
• Requires approximately 500 mL blood to have accumulated before reliable detection.
• A negative test does not exclude intra-abdominal haemorrhage.
• Operator dependent.
• Views limited by surgical emphysema, bowel gas, or obesity.
• Does not identify which organ is injured or the type of fluid, e.g. blood or bowel contents.
FAST assesses the presence of free fluid (black) in four areas:
• Hepatorenal recess in right upper quadrant (between liver and right kidney).
• Splenorenal recess in left upper quadrant (between spleen and left kidney).
• Pouch of Douglas in pelvis (behind the bladder).
• Pericardium (around the heart).
If haemodynamically unstable patient
• FAST positive: needs laparotomy.
• FAST negative: look for other sources of haemorrhage.
Diagnostic peritoneal lavage
This used to be the investigation of choice for identifying abdominal injury in unstable patients in the Resuscitation room or where other radiological investigations were not available. It has been superseded in most centres by use of FAST ultrasound and the availability of CT scans. The test is invasive, with risk of iatrogenic damage to abdominal organs, and there is a high rate of false positive tests.
Prior to diagnostic peritoneal lavage (DPL) the bladder is decompressed with a urinary catheter and the stomach with a NGT. The procedure involves cleaning the skin and injecting local anaesthetic at the site of puncture midline just below the umbilicus. The skin is elevated with forceps, and incised down to fascia and then through peritoneum. A peritoneal dialysis catheter is inserted into the peritoneal cavity and aspirated. If this is negative, 1 L of warmed sodium chloride 0.9% is instilled via the catheter, agitated, and then re-aspirated. A sample of the fluid is sent to the laboratory.
A positive scan is free aspiration of >10 mL of blood, gastrointestinal contents or bile, or on lavage >100,000 red blood cells (RBC), >500 white blood cells (WBC) or a positive Gram stain test. A negative test does not exclude retroperitoneal injury or diaphragmatic tears.
CT scan may be performed as part of a total body CT scan in the multiple-injured patient or to specifically evaluate abdominal injuries. Intravenous contrast is used, and the scan includes the top of diaphragm (to identify haemothorax or pneumothorax) down to the pubic symphysis and pelvis.
The advantage of CT is visualization of retroperitoneal structures, detection of arterial contrast extravasation and the ability to grade solid organ injury, which may allow non-operative management. It may miss some diaphragmatic, hollow viscus, or early pancreas injuries.
Disadvantages include exposure to ionizing radiation and side effects of intravenous contrast. The main limitation of CT is it cannot be used in haemodynamically unstable patients. However, in experienced trauma centres with modern high-speed CT scanners situated in proximity to the Resuscitation room and a specialized senior team accompanying the patient, transient responders to resuscitation may also be scanned. This decision must be made by a senior experienced Trauma team leader.
Angiography may be useful to accurately diagnose bleeding sites and therapeutically embolize vessels. This is particularly useful following complex pelvic fractures and in solid organ injury with vascular damage.
This is the commonest cause of abdominal trauma in the UK. The most commonly injured organs are the liver and spleen.
• Crush injury, e.g. industrial.
• Fall from height.
• Direct blow, e.g. punch, kick from horse.
Pattern of injury
• Direct impact causing compression or crush injury.
• Deceleration, shearing and rotational forces.
• Increased intra-luminal pressure causing injury to hollow viscus.
Indications for further investigation
• Mechanism of injury gives high index of suspicion.
• Injuries above and below abdomen, e.g. chest and femurs.
• Clinical signs including bruising.
• Difficult to assess for abdominal injury, e.g. reduced conscious level, distracting injury, spinal injury.
• Lower rib fractures may suggest liver or splenic injury.
This may be an option for certain isolated blunt liver, spleen, or renal injuries. The decision must be made by a senior surgeon with awareness that the patient may deteriorate and require surgical intervention later. The indications are:
• Injuries to solid organs demonstrated by CT to be appropriate for non-operative management.
• Minimal physical signs.
• Haemodynamically stable (<2 units of blood transfused).
• HDU/ICU bed available to observe patient.
• Senior surgeon available to perform repeated serial examinations and perform urgent laparotomy if later required.
Explosions from domestic gas, industrial sites, or bombs may cause abdominal injury by:
• Primary blast wave: causing perforation of bowel or shearing of mesentery or solid organs (without any external signs of injury).
• Secondary fragmentation injury: penetration of abdominal cavity by bomb materials or flying debris.
• Tertiary blunt injury: from being thrown by the blast wind.
Signs and symptoms of primary blast injury
• Abdominal pain, nausea and vomiting, tenesmus, testicular pain.
• Abdominal distension and tenderness.
• Rectal bleeding.
• Tachycardia and hypotension.
• Assess and treat any life-threatening airway or chest injury.
• Manage as blunt or penetrating abdominal injury according to findings.
• Admit for observation if there are no obvious features of abdominal injury on examination or investigation, as there is a high risk of delayed intestinal perforation (up to 10 days).
• Low threshold for laparotomy.
Stab wounds are still more common than GSW in the UK. Injuries depend on the energy transferred by the penetrating object and the trajectory.
• A full history should include the time of injury, type of weapon or round, distance from assailant, number of wounds or shots, position of patient when penetration occurred, and the amount of external bleeding at scene.
• It is essential to fully expose the patient early in the primary survey to identify any concealed wounds. This includes the back, flanks, groins, buttocks, and perineum plus a rectal examination.
• Beware: the size of the external wound does not determine the likelihood or severity of intra-abdominal injuries.
• In a conscious patient check for a spinal cord injury by assessing the neurological status of the limbs.
• Plain X-ray may be useful in stable patients to identify the location of any retained bullet and allow prediction of the trajectory, e.g. has it gone from chest to thigh, passing through the thorax and abdominal cavity?
Any foreign body or knife must only be removed in theatre at laparotomy under direct vision to enable control of any potential haemorrhage or contamination.
• Cover wound with sterile dressing. Any protruding bowel or omentum should be covered with warm saline soaked swabs, and not handled or pushed back into the abdomen.
• Check tetanus status and consider need for prophylaxis.
• Give IV antibiotics according to local prescribing guidelines.
Local wound exploration
Local wound exploration is the evaluation of a stab wound using local anaesthetic before extending and probing the wound. This should only be performed in theatre by a surgeon who will be able to proceed to laparoscopy or laparotomy if it is indicated. Exploration is positive when the anterior fasica or peritoneum has been breached. There is no role for wound exploration in GSW: these should all have a laparotomy.
Serial examination has good sensitivity and negative predictive value for evaluating patients with minor penetrating abdominal trauma. The patient is admitted for observation for at least 24 h with hourly assessment of haemodynamic status and at least 4-hourly assessment for clinical abdominal signs. If the patient develops any signs of bleeding or peritonism during this period of observation a laparotomy is performed. If they develop a pyrexia, tachycardia, or localized tenderness a CT scan, laparoscopy, or laparotomy is performed. If after 24 h, the patient remains well they can start a normal diet and discharge can be considered.
Indications for laparotomy
• Stab wounds with peritoneal penetration.
• Any GSW to the abdomen.
• Retained foreign bodies.
• Haemodynamically unstable with penetrating abdominal injury.
• Haemodynamically stable with positive CT scan.
Ensure a member of staff informs the police that you have ‘a patient’ in the department with a stab wound or GSW. If the patient has arrived by the ambulance service they will usually be accompanied by a police officer. It is justifiable to break confidentiality when there are issues of public interest, and to protect the safety of your department and staff. Consult the General Medical Council website and the MPS/MDU for further information.