Abdominal Compartment Syndrome Workup

Updated: Jan 30, 2023
  • Author: Richard Paula, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
  • Print

Lab and Imaging Studies

Laboratory studies and abdominal computed tomography scan are part of the workup for abdominal compartment syndrome. Measure intra-abdominal pressure (IAP) if abdominal compartment syndrome is suspected. IAP can be easily monitored by measuring bladder pressure. [41]

The following lab studies may be indicated:

  • Comprehensive metabolic panel (CMP)

  • Complete blood cell count (CBC)

  • Amylase and lipase assessment

  • Prothrombin time (PT), activated partial thromboplastin time (aPTT) if the patient is heparinized

  • Cardiac marker assays

  • Urinalysis and urine drug screen

  • Measurement of serum lactate levels (at many institutions, the sample must be kept on ice)

  • Arterial blood gas (ABG): This is a quick way to measure the pH, lactate, and base deficit

Abdominal CT scanning can reveal many subtle findings. Pickhardt et al found the following in patients with abdominal compartment syndrome [42] :

  • Round-belly sign: Abdominal distention with an increased ratio of anteroposterior-to-transverse abdominal diameter (ratio >0.80)

  • Collapse of the vena cava

  • Bowel wall thickening with enhancement

  • Bilateral inguinal herniation

Plain abdominal radiographic studies are often useless in identifying abdominal compartment syndrome, although they may show evidence of free air or bowel obstruction. Abdominal ultrasonography may reveal an aortic aneurysm, particularly with large aneurysms, but bowel gas or obesity makes performing the study difficult.


Intra-abdominal Pressure Measurement

IAP can be easily monitored by measuring bladder pressure. Measurement of intraluminal bladder pressure consists of instilling about 25 mL of saline into the urinary bladder through the Foley catheter. The recommended volume is 25 mL, but studies have demonstrated similar measurements using only 10 mL. [43] The tubing of the collecting bag is clamped, and a needle is inserted into the specimen-collecting port of the tubing proximal to the clamp and is attached to a manometer. Bladder pressure (measured in mm H2O) is the height at which the level of the saline column stabilizes with the symphysis pubis as the zero point. [41, 44, 45, 3]


In an excellent group of articles, Burch et al developed a grading system. [46] Patients with higher-grade abdominal compartment syndrome have end-organ damage, which is evidenced by splenic hypercarbia and elevated lactate levels, even if they appear clinically stable. The following grading system has become accepted if IAH is present:

  • Grade I: 10-15 cm H2 O

  • Grade II: 15-25 cm H2 O

  • Grade III: 25-35 cm H2 O

  • Grade IV: >35 cm H2 O

End-organ damage has been observed with IAP as low as 10 cm H2O, and multiple studies have found damage at values ranging from 20 to 40 cm H2O. Disparity exists because abdominal compartment syndrome never occurs as an isolated event.

Cheatham et al found abdominal perfusion pressure (APP) to be a much better predictor of end-organ injury than lactate, pH, urine output, or base deficit. [44] The APP is equal to the mean arterial pressure minus the IAP.