Frequently missed abdominal compartment syndrome.

Intra-abdominal pressure (Intra-abdominal pressure – IAP) is defined as static pressure inside abdominal cavity, that fluctuates with respiration, physical exercise and change in body position. It is determined by total volume of internal organs and concurrent organ dysfunction (blood, fluid, tumors or factors reducing relaxation of abdominal walls). IAP should be expressed in (mm Hg)and measured at the end of expiration with patient in supine position, with no abdominal contractions. Clinical assessment of IAP is of little sensitivity and inadequate. There are two methods of IAP measurement: direct – intraoperative, using trocar or drain located in peritoneal cavity, and indirect – recording intra-abdominal pressure in gastric cavity, anus, vena cava inferior, and urine bladder (Intra-Vesical Pressure; IVP). IVP is the easiest and the fastest method to measure IAP and serves nowadays as the golden standard. It was first introduced by Kron in 1948 (1). It is done through indwelling bladder catheter, instilling 50-100 ml of sterile saline into the bladder connected to a T-connector. The catheter is then clamped and intravesical pressure is measured, at the end of expiration, using manometer/pressure transducer connected to the other arm of the Tconnector. The symphysis pubis is used as a zero reference point. During this procedure the urine bladder wall, with such filling, is assumed to act as membrane that transfers intra-abdominal pressure fluctuations (2, 3, 4). The disadvantage of such method is that in case of spastic bladder and intraperitoneal adhesions – due to lack of pressure transduction between different regions of abdominal cavity – IVP does not reflect IAP.