History and exam

Key diagnostic factors

common

abdominal distension

A tense, distended abdomen is the most important clinical sign.

oliguria

Urine output is decreased due to impaired renal blood flow and decreased urine production.

increased respiratory effort

Patients have difficulty maintaining minute ventilation and oxygenation due to a decrease in pulmonary compliance produced by transmission of abdominal pressure to the torso.

Atelectasis can also occur.

hypotension

Increased intra-abdominal pressure compresses the inferior vena cava and impairs venous return to the heart, leading to decreased preload and cardiac output.

Risk factors

strong

excessive fluid resuscitation (>3 L in 24 hours)

Oncotic and hydrostatic effects of large-volume fluid resuscitation lead to increased amounts of extracellular and extravascular fluid, causing gut edema and ascites. Both increase intra-abdominal pressure.

massive blood transfusion (>10 units in 24 hours)

Hydrostatic effects of massive blood transfusion lead to increased amounts of extracellular and extravascular fluid, causing gut edema and ascites. Both increase intra-abdominal pressure.

decreased abdominal compliance

Abdominal compliance is determined by the elasticity of the abdominal wall and diaphragm. Conditions such as severe obesity, burns with abdominal wall eschars, and severe ventilator dyssynchrony with use of accessory muscles can decrease abdominal compliance, which can significantly increase IAP.[14]

intra-abdominal infection/inflammation

Intra-abdominal infections, primarily those causing generalized peritonitis, can lead to an intensive inflammatory response in the peritoneal surfaces and the gut.

Significant fluid resuscitation and surgical intervention are often required, both of which increase gut edema and the generation of peritoneal fluid.

The inflammatory response in severe acute pancreatitis leads to ACS in approximately 40% of cases, with a significant increase in mortality.[7][8]

hemoperitoneum

Patients require fluid resuscitation and massive transfusion, and will therefore also have gut edema and ascites.

Hemoperitoneum can produce intra-abdominal pressures high enough to cause ACS. However, because fluid resuscitation is instigated early, hemoperitoneum in combination with ascites and gut edema is more common.

weak

ileus

Any process that decreases or impairs the normal transit of bowel contents can produce accumulation of luminal contents, leading to distension of the bowel and an increase in intra-abdominal pressure.

pneumoperitoneum

Can arise from perforation of a peptic ulcer or diverticulum, or it can be iatrogenic prior to laparoscopy. In the case of perforation, peritoneal inflammation increases, with consequent intestinal edema and peritoneal fluid production. In the iatrogenic case, induced pneumoperitoneum generally only leads to ACS when the upper pressure limit is set inappropriately high.

loss of abdominal domain

The term "loss of abdominal domain" refers to a situation in which more of the viscera are located outside the abdominal cavity than inside because the abdominal cavity is unable to accommodate all of the abdominal contents within its fascial boundaries.

Patients who are undergoing a repair of large ventral hernia with previous loss of domain are at risk for developing increased abdominal pressure after hernia closure.[15]

comorbid cirrhosis

Patients with advanced cirrhosis may have large volumes of ascitic fluid present at baseline and are at increased risk if intra-abdominal pressure is increased by another cause.

retroperitoneal hematoma

Mass effect from the hematoma causes an effective loss of intra-abdominal volume, with a resultant increase in IAP. It has been described in patients who have spontaneous retroperitoneal bleeds from anticoagulation and from endovascular procedures that cause bleeding.[16][17]

Use of this content is subject to our disclaimer