Surgery STAT: Emergency management of hemoabdomen

Editor's Note: SurgerySTAT is a collaborative column between the American College of Veterinary Surgeons (ACVS) and DVM Newsmagazine.

Hemoabdomen, defined as the accumulation of blood within the peritoneal cavity, is a relatively common finding in dogs but rare in cats. The underlying cause of hemoabdomen can be either traumatic or spontaneous. The most common cause of traumatic hemoabdomen is a motor vehicle accident, but penetrating trauma can also result in abdominal bleeding.

Spontaneous hemoabdomen is caused by neoplasia 80 percent of the time in dogs but only 46 percent of the time in cats. The spleen is the most common organ in both species to develop neoplasia, and hemangiosarcoma is the most common diagnosis. Regardless of the cause, intra-abdominal hemorrhage can be life-threatening. Patients with evidence of shock should have an intravenous catheter placed for immediate volume resuscitation. Diagnostic testing should initially be limited to rapid assessment of packed cell volume (PCV) and total solids and an abdominocentesis. Hemoabdomen can be diagnosed if blood that does not clot is retrieved by abdominocentesis.

Fluid therapy

The goals of initial resuscitation are to correct hypovolemia and stop further hemorrhage. Fluid resuscitation is imperative because prolonged hypotension will compromise organ perfusion. Traditionally, rapid infusion of a large volume of fluid has been recommended, but overly aggressive fluid administration can exacerbate hemorrhage by disrupting clots and diluting clotting factors.

Boluses of isotonic crystalloids in 15- to 20-ml/kg increments should be given until an improvement in perfusion is seen (heart rate, respiratory rate, pulse quality, body temperature) and the mean arterial pressure reaches 60 mm Hg or a systolic blood pressure of 80 to 90 mm Hg is achieved. Colloid boluses (i.e., 5 ml/kg hetastarch) can also be given in addition to crystalloids. The total volume of colloid administered should not exceed 40 ml/kg/day to avoid prolonged clotting times.

Transfusion

Blood products should be given based on the rate and quantity of blood lost, but, in general, bleeding dogs and cats with a PCV < 25 percent are candidates for transfusion. Blood typing should be performed before transfusion, but in dogs with no history of previous transfusion, a donor that has a negative test result for dog erythrocyte antigen 1.1 can be safely used.

Fresh whole blood is the most effective fluid for hemorrhagic shock, and 2 ml/kg of whole blood can be expected to raise the PCV 1 percent. Packed red blood cells (RBCs) at a dose of 1 ml/kg will also result in a 1 percent increase in PCV. For hemorrhage resulting from a coagulopathy, fresh frozen plasma should be given at a starting dose of 6 to 10 ml/kg. If the coagulopathic patient has a PCV < 25 percent, either fresh whole blood or a combination of packed RBCs and fresh frozen plasma can be used.

Autotransfusion is performed when blood products are not readily available and if there is no evidence of concurrent uroperitoneum, septic peritonitis or, ideally, neoplasia. With autotransfusion, the blood is collected aseptically and administered through a blood administration set or in-line filter. Blood is defibrinated when it has been in contact with the peritoneum for longer than 45 minutes, so the addition of anticoagulants is only needed if the bleeding is extremely acute.

Abdominal wrapping

A tight compressive bandage placed around the abdomen has been shown to slow blood loss and increase survival. The bandage should be started at the pubis and extend cranially to the level of the xyphoid. Once the patient has been stabilized, the bandage can be slowly removed by cutting it cranially to caudally in small increments every few minutes. Removing it too quickly can result in a rapid drop in blood pressure.

Table 1

If shock recurs after bandage removal, resuscitative fluid therapy is restarted, and the need for emergency surgery is considered. This technique is contraindicated in patients with respiratory compromise, diaphragmatic hernia or head trauma.

Further diagnosis and treatment

Additional diagnostic tests should be performed once the patient is stable. A coagulation panel should be performed if a coagulopathy is suspected. Abdominal radiography will show decreased serosal detail and may reveal a mass or evidence of organ displacement (Figure 1). Ultrasonography is generally more useful in identifying the source of hemorrhage and can also facilitate abdominal fluid collection. Thoracic radiographs should be obtained in patients with trauma to rule out concurrent injury and in patients with an abdominal mass to rule out metastasis. Indications for laparotomy in patients with either traumatic or spontaneous hemoabdomen are listed in Table 1.

Figure 1: A ventrodorsal radiograph of the abdomen of a dog with a ruptured splenic mass and hemoabdomen. There is loss of serosal detail, and the intestines are displaced to the right.

Prognosis

In general, hemoabdomen due to blunt trauma can usually be managed with abdominal wrapping and supportive care. The survival rate in dogs is about 70 percent whether they are treated surgically or medically. The survival rate for pets with spontaneous hemoperitoneum is widely variable, depending on the cause.

Dr. Ludwig works in a private small-animal referral practice in Charleston, S.C. She is a national and an international speaker in several areas in soft tissue and emergency surgery and has written several articles in both veterinary journals and textbooks.