Abdominal trauma: Clinical practice

Abdominal trauma is defined as injury anywhere between the nipple line and inguinal creases, and can be blunt, like from motor vehicle accidents, or penetrating, like from stab wounds or gunshot wounds.

As with any trauma, evaluation begins with the primary survey, which includes the ABCDEs; airway, breathing, circulation, disability and exposure.

The main goal of the primary survey is to assess and treat for immediately life-threatening injuries.

Okay, so if the individual is talking to you with a clear voice, their airway is intact. If not, assess their ability to maintain the airway, or if they needed assisted ventilation with a bag-valve mask or even endotracheal intubation.

As for “breathing”, look for tracheal deviation and listen to the breath sounds.

Also, if the individual is hypoxic, provide 100% oxygen using a non-rebreather mask.

Next, look at the heart rate and blood pressure, as tachycardia or hypotension may indicate hemorrhagic shock.

Assess for signs of inadequate end-organ perfusion, such as altered mental status, decrease urine output, cool or pale skin, and delayed capillary refill.

Also, insert two large-bore intravenous lines, and prepare for the need for blood products.

Bedside ultrasound can also be used in the primary survey - and it’s called focused assessment with sonography for trauma, or the FAST exam.

The ultrasound probe explores the pericardial cavity, then the right flank, also called the hepatorenal recess or Morison’s pouch, and then the left flank which looks for perisplenic fluid, and finally the suprapubic region to look for fluid around the bladder.

When views are added to look for a pneumothorax, hemothorax, or cardiac tamponade, it’s called an extended FAST or E-FAST.

The FAST exam is non-invasive, portable, and great at detecting intra abdominal bleeding, but it does require skill to use it properly and doesn’t identify which organ is injured.

For example, fluid in the hepatorenal space does not necessarily mean hepatic injury.

Finally there’s “Disability” which means neurological disability, and is assessed by checking the pupils and using the Glasgow Coma Scale, or GCS.

And there’s “exposure” which is assessed by turning the individual on their side, and assessing their back for any occult injuries.

All right, now the secondary survey focuses on taking a history, and performing an elaborate head-to-toe examination with the goal of detecting more subtle injuries.

Ecchymosis over the periumbilical region, also called Cullen's sign, or on both flanks, also called the Grey-Turner sign respectively signify intraperitoneal and retroperitoneal hemorrhage from pancreatic injury.

Referred pain to the left shoulder when palpating the left upper quadrant is Kehr's sign, which indicates splenic injury irritating the left hemidiaphragm.

A seat belt sign is a diagonal ecchymosis across the abdomen in the distribution of a seatbelt, and this clues towards small bowel injury or a transverse fracture of the L3 vertebrae, also called a Chance fracture.

Signs of peritoneal irritation such as guarding and rebound tenderness may be present, but the absence of these findings don’t rule out an abdominal injury.

Common labs that are sent include a CBC, blood type and crossmatch, and a PT, PTT, and INR.

Also, a urine beta-hcG should be obtained for any female of childbearing age.

A urinalysis should be obtained to look for hematuria, which could be due to genitourinary injury.

And because bleeding from trauma causes a loss of platelets and coagulation factors, in addition to a loss of RBCs, it’s important to replace them all.

So, packed red blood cells, or PRBCs, platelets, and fresh frozen plasma or FFP are all given in a one-to-one-to-one ratio. In other words, if you’re giving 3 units of PRBCs, you’ll also give 3 units of platelets, and 3 units of FFP.

Additionally, because gram-negative and anaerobic bacteria live in the gut, prophylactic antibiotics like piperacillin-tazobactam are given to decrease the risk of an intra-abdominal source of sepsis.

Management of blunt abdominal trauma depends on the individual’s hemodynamic stability.

If they’re hemodynamically unstable, and the FAST exam shows free fluid, they should immediately get an exploratory laparotomy.

If the FAST exam doesn’t show free fluid, then resuscitation is continued, and other causes of hemorrhagic shock should be searched for - like bleeding from a pelvic or long-bone fracture.

After that the FAST exam is repeated, and a diagnostic peritoneal lavage, or DPL can be done.

A DPL involves inserting a needle into the abdomen, aspirating a fluid sample, and sending it off to for a microscopic analysis.

In a hemodynamically unstable individual, if there’s gross blood, or more than 100,000 RBCs, or more than 500 WBCs on the microscopic analysis, then an exploratory laparotomy should be done.

Now, if the individual is hemodynamically stable and their FAST exam is negative for free fluid, then serial abdominal exams are performed every couple of hours.

Some individuals are sent for a CT scan of the abdomen, depending on the clinical suspicion of intra-abdominal injury.

On the other hand, if the FAST exam shows free fluid, then the next step is definitely a CT scan of the abdomen.

The CT can show specific organ injuries, as well as retroperitoneal injuries, but it can miss pancreatic, diaphragmatic, small bowel, and mesenteric injuries.

If the CT scan is positive, then the next step is either non-operative management or an exploratory laparotomy, depending on the type and severity of the injury.

All right, now in penetrating abdominal trauma, the primary and secondary survey are similar.

Also, the FAST is routinely performed, but unlike blunt trauma, it’s less helpful and isn’t used in isolation as a reliable decision making tool.

It’s also usually done as an E-FAST exam, because the concern for pneumothorax or hemothorax in penetrating trauma is greater than in blunt trauma.

Another difference is that individuals with penetrating abdominal trauma should receive a tetanus toxoid vaccine.

Prophylactic broad-spectrum antibiotics are typically given to those that need surgical intervention.

Finally, if an object like a knife is impaled, it’s important to leave it in place until it can be surgically removed to prevent uncontrolled bleeding.

Okay, now when it comes to stab wounds, the liver is the most commonly injured organ.

An emergent exploratory laparotomy should be done if there’s hemodynamic instability, impalement or evisceration of abdominal contents, signs of peritonitis such as guarding or rebound tenderness, or signs of gastrointestinal hemorrhage such rectal bleeding or a bloody aspirate from a nasogastric tube.

If none of these are present, the next step is to determine if there’s penetration into the peritoneal space - specifically if the anterior rectus fascia was penetrated. This can be done with a FAST exam, which will show free fluid, done in conjunction with exploring the wound under local anesthesia.

If there doesn’t seem to be peritoneal penetration, then the wound should be cleaned and closed.

If there is peritoneal penetration, a CT scan is done to delineate specific organ injuries, then the individual is observed for 12 to 24 hours, and during that time serial abdominal exams are done every few hours.

If they develop hemodynamic instability or signs of peritonitis, they’re taken for an exploratory laparotomy.

If the individual remains hemodynamically stable, doesn’t develop signs of peritonitis, and is otherwise stable, they’re typically discharged home.

Okay, now for gunshot wounds, the small and large bowel are most commonly injured.

Indications for emergent exploratory laparotomy include hemodynamic instability, and signs of peritonitis or evisceration. If none of these are present, then assessment for peritoneal perforation is done using a CT scan.

Now unlike stab wounds, gunshot wounds almost always penetrate the peritoneum and cause intraperitoneal organ injury.