An observational study on intraabdominal pressure in 125 critically ill patients

Elevated intraabdominal pressure and the abdominal compartment syndrome seem to be the recent hype at critical care conferences. The objective of this longitudinal, observational study is to document epidemiologic data on intraabdominal pressure (IAP) in patients admitted to a mixed medical and surgical intensive care department (ICU) of an university hospital and to determine the value of routine monitoring of IAP.

All adult patients admitted for an expected minimum stay of 48 hours in the ICU were included, provided that they needed an indwelling urinary bladder catheter. Included patients were followed until discharge from the ICU or until death, whichever came first. Final outcome at hospital discharge was determined. The IAP was measured in a non-invasive manner through the aspiration port of a standard indwelling bladder catheter, in a modification of the procedure as originally described by Kron et al. The IAP was measured twice daily until discharge from the ICU or until there was no further need of a bladder catheter (i.e. a bladder catheter was not left in place for the sole purpose of measuring IAP). Furthermore, demographic, pathologic, and diagnostic data, as well as physiologic, hemodynamic, and biochemical parameters were recorded. Several disease severity scores were calculated.

We present the results of the first 125 patients included. A total of 1451 measurements were performed. Patients were stratified into two groups depending on 30-day survival or outcome at discharge from hospital. Forty-one patients (652 measurements) did not survive. Mean IAP for this group was 8.9 (range -6 to 24, SD 4.5). We recorded 130 IAP-values over 12 mmHg (20%) of which seven IAP-values over 19 mmHg (1%) in six patients. Eighty-four patients (799 measurements) had a favourable outcome. Mean IAP for this group was 7.6 (range -6 to 30, SD 4.6). We recorded 112 IAP-values over 12 mmHg (14%) of which 10 IAP-values over 19 mmHg (1%) in five patients. The two-tailed student's t-test for the IAP between the two groups was significant (P < 0.0001). However, elevation of IAP-values did not necessarily coincide with demise. We could not demonstrate a linear correlation between IAP-values and values of other parameters.

From our present data we can conclude that IAP is generally higher in non-survivors than in survivors, but that survivors can have elevated values of IAP. Routine monitoring of IAP in all patients admitted to the ICU does not seem warranted.