Patient Care, Trauma

Many Elements Involved in Penetrating Abdominal Wounds

Issue 4 and Volume 36.

EMS responds to a “bar fight” with unknown injuries. On arrival, the crew finds three patients. Patient No. 1 has lacerations to his right forearm and above his right eye; patient No. 2 has multiple abrasions to the face; patient No. 3 is complaining of abdominal pain and initially shows signs of a wound to the abdomen.

Police tell the crew that a 10″ kitchen knife was found near patient No. 1. Their rapid assessment reveals that patients No. 1 and 2 are stable, have no active bleeding and are oriented. Patient No. 3 is sitting on the ground propped against a wall. His vital signs are pulse 103, blood pressure 98/40, and respirations 22 and shallow. He responds to verbal commands but is complaining of pain in his left upper quadrant. A small wound is noted just below the rib cage with minor exterior bleeding.

The key issue here involves the following questions: How badly is patient No. 3 injured? Did the knife penetrate his peritoneum, entering his abdomen? Is the injury in the abdomen or thorax? Does it involve or affect his lung?

In penetrating wounds to the abdomen, there are multiple organs, blood vessels and layers of fat to absorb or deflect the penetrating object, making organ damage nearly impossible to clearly identify. The best indicators of possible derangement of abdominal contents are the entry point and a good physical exam. It’s also helpful to develop an index of suspicion, anticipating the potential injuries when dealing with penetrating trauma. The key to survival for these patients is rapid stabilization and transport to the nearest trauma center.

The major contributing factor in mortality from abdominal trauma is hemorrhage. Because of the large number of blood vessels and organs packed into the abdominal area, these patients are at an increased risk of significant hemorrhage even with a seemingly small wound. Blood from penetrating wounds to the abdomen can pool in the anterior abdomen, pelvis and retroperitoneum. Each can hold well over 1 L of fluid without external signs.

With the number of patients on long-term blood thinners increasing, it’s important to understand how these drugs add to the risk of mortality from abdominal hemorrhage. The anticoagulant warfarin (coumadin) works by altering the clotting cascade, and clopidogrel (Plavix) and aspirin work by decreasing the ability of platelets to form a clot. Using different pathways, these drugs increase clotting time, which also increases the risk of major bleeding and death.

Proper exposure of the stab site is a critical part of prehospital care. If a sucking chest wound exists, the EMS providers must identify it and ensure it’s properly sealed. If an evisceration has occurred in an abdominal wound, the organ must not be pushed back in, but covered with a moist dressing and protected.

Anatomy & Examination
First, we need to establish the size of the abdomen. It extends from the bottom of the diaphragm to the pelvic ligaments, from the abdominal wall to the spine, and from side to side.(1) The inside of the anterior abdomen is lined with the peritoneum, a membranous layer just below the skin. This is the largest of the cavities within the abdomen.

The bladder, and the uterus in females, are in the inferior portion of the abdominal cavity. Due to the way the abdomen tips, it forms the pelvic cavity. The retroperitoneal cavity lies behind the anterior abdomen encased it its own membranous sac. The aorta, vena cava and kidneys reside in the retroperitoneal cavity.

The abdomen is divided into four quadrants for ease of examination, description and documentation. The quadrants are labeled right upper, right lower, left upper and left lower. They correspond to specific abdominal organs, helping establish your index of suspicion for organ and blood vessel damage.

The right upper quadrant contains the liver, gallbladder and right kidney. The right lower quadrant contains the ascending and half the transverse colon and a portion of the small bowel. The left upper quadrant contains the stomach, spleen and left kidney. The left lower quadrant contains the remainder of the transverse colon as well as the descending and sigmoid colon and small bowel. The pancreas straddles the right and left upper quadrants, and the urinary bladder straddles the right and left lower quadrants. Female organs also reside in both the right and left lower quadrants and the uterus straddles the two lower quadrants.

In addition to the organs, major blood vessels are also located in each quadrant. The aorta is generally midline, and inferior vena cava is just right of midline. These vessels are located in the retroperitoneal cavity near the spinal column. The renal arteries are also located in the retroperitoneal cavity, branching off the aorta at the level of the lower thoracic spine. The hepatic artery and vein are primarily located in the right upper quadrant. Bifurcation of the aorta occurs at about the level of the bladder and femoral arteries exit through the right and left lower quadrants.

Examination of the abdomen should begin with visual inspection and auscultation of the entry wound, if possible. Don’t start the abdominal exam with deep palpation because this can worsen intra-abdominal bleeding, and it’s not a reliable indicator of pelvic or retro-peritoneal bleeding, especially in obese patients. Identifying a rigid section of abdominal wall with light palpation usually indicates intraperitoneal rupture of a blood vessel or hollow organ, such as the bowel. This condition can lead to sepsis from spilled bowel contents or increased mortality from a ruptured vessel.

Special Circumstances
It’s important to understand the anatomy of the abdomen and how it corresponds with the various quadrants. It will help you provide a better report, even though you aren’t going to be able to determine the exact location or extent of the bleeding. The following are special circumstances that you should be aware of when evaluating and triaging a patient with an abdominal wound.

Pneumothorax: With each inspiration and expiration, the diaphragm moves up and down, changing the size and location of upper quadrant organs. Expiration moves the liver, spleen and stomach into the lower portion of the rib cage, exposing these organs to damage when there’s an injury to the chest. With a deep breath, the lungs are brought down into the upper quadrants of the abdomen, leaving the lungs at risk for injury.

When a patient has suffered a penetrating wound to the lower portion of the ribs, always include a thorough evaluation of lung sounds to rule out pneumothorax. Close monitoring and supplemental oxygen are important considerations when caring for these patients.

Some penetrating abdominal wounds can result in evisceration, a protrusion of the organs outside the abdominal wall. There are two main causes for evisceration. The first is a large wound that extends through the peritoneum, causing a sudden eruption of abdominal contents. The second is more subtle; it’s a small wound with minimal bleeding when the patient develops intra-abdominal pressure. The pressure will be released through any available opening, often sending abdominal contents to the surface.

Care of eviscerated organs requires attention to detail. These extruded body parts are usually surrounded by sterile fluid and protected from air, so treatment must recreate this protective environment. Handle the organs as little as possible. When you need to move them, use a sterile sheet unless you carry sterile gloves. Cover the organs in sterile gauze or a sheet and wet them down with sterile saline. It’s vital to organ survival that organs remain covered and moist
during transport.

Arterial bleeding: As discussed in the previous section, several major blood vessels are in the abdomen. When dealing with a penetrating wound around the umbilicus, consider that the aorta may be involved. This injury has a low probability of survival, and there should be no delay in transport.

When a patient suffers a penetrating wound to the flank, you should be highly suspicious of a laceration of the renal vasculature or the kidneys. Both of these scenarios require early surgical treatment to stem blood flow and preserve kidney function.

Organ damage: The abdomen consists of two types of organs, hollow and solid. Hollow organs are reservoirs of bodily fluids or conduits for excretion of body waste. Examples of hollow organs include the stomach, intestines and urinary bladder. Penetrating injuries to these organs will result in spillage of bacteria, partially digested food and other waste products. Vascular injuries can also be expected with penetrating injures involving hollow organs. Besides hemorrhage, the biggest risk is peritoneal infection.

Solid organs, such as the kidney and spleen, are organs of filtration, which means they’re dense and contain massive amounts of blood vessels. The biggest risk in this patient population is hemorrhage, and the only course of treatment is surgical intervention. Unlike hollow organs, the content of these organs is blood, so although less risk of peritoneal infection exists, hemorrhages can still occur.

You place an oxygen mask on the patient but notice he still seems to be working hard to breathe. An assessment of his left lung reveals diminished lung sound, but the pulse oximeter reading is staying at 95% with the non-rebreather. Light palpation of the abdomen reveals rigidity in the left upper quadrant and elicits a cry of pain from the patient. This raises your index of suspicion for an injury to the spleen with intra-abdominal hemorrhage. Two IVs are started, and the patient is transported to the nearest trauma center.

In this case, many elements are involved in the assessment and management of penetrating abdominal trauma. Considerations during the assessment phase should include characteristics of the penetrating projectile, location of the wound and a high index of suspicion if the patient is bleeding. You should also consider medications when evaluating and determining the severity of the injury.

Remember that surgery is the only treatment for a severe injury to the abdomen, so rapid transport to the nearest trauma center is of utmost importance. JEMS

1. Aehlert B. Paramedic Practice Today, Volume 2. Mosby: St. Louis, 491, 2009. 

This article originally appeared in April 2011 JEMS as “Below the Surface: Tips for assessing abdominal injuries.”