When Pressed to Check the Pressure

Estimating a patient's intra-abdominal pressure (IAP) can be a challenge when the patient is not in an ICU setting and abdominal compartment syndrome or intra-abdominal hypertension are suspected.  Here is a quick method for estimating IAP. This is a much simpler version of the method reported by Cheatham et al and only requires a measuring tape, 25 mL of normal saline in a syringe and a tubing clamp.  The attached picture is of a patient that I tried this method on today. Only took 5 minutes from start to finish.

1.  Make sure that Foley's tubing is empty by draining all the urine into the bag.

2.  The patient should be supine.  Hang the urine bag up on the patient's IV stand 2.5-3 feet above the bed.

3.  Clamp (or pinch/kink) the tube just distal to the hub and then have the nurse inject 25 mL of normal saline through the Foley into the bladder.  The normal saline should be at room temperature.

4.  As the column of urine rises in the tube, measure the height of the column in centimeters by holding the measuring tape as shown with the zero approximately at the point of the iliac crest where the mid axillary line passes.

5.  Divide the height in centimeters of the column by 1.36 to get the pressure in mmHg.

The cut off (2) for intra-abdominal hypertension is 12 mmHg and that for compartment syndrome is 20 mmHg (with organ dysfunction).  In this patient with oliguric acute kidney injury developing after a bowel surgey, the pressure was 26 mmHg, suggesting abdominal compartment syndrome as the etiology.

Also see Mohmand and Goldfarb Editorial in NephSAP 10(3) May 2011.

Hashim Mohmand MD.