Background: Raised intra-abdominal pressure (IAP) or intra-abdominal hypertension (IAH) may induce many adverse effects including the abdominal compartment syndrome. We evaluated a new technique for continuous monitoring of intra-abdominal pressure (CIAP) using a standard three-way bladder catheter in a diverse group of intensive care unit patients.
Methods: CIAP measured using a standard three-way bladder catheter was compared with five standard intermittent IAP (IIAP) measurements in 79 patients.
Results: Mean (standard deviation) CIAP was identical (15.4 mm Hg [5.8]) for CIAP and IIAP one minute after saline injection. Mean differences between methods were less than 1 mm Hg, and similar whether IIAP was measured at 1 minute, 2 minutes, 3 minutes, 4 minutes, or 5 minutes. Bland-Altman analysis comparing CIAP and IIAP (1 minute) revealed a mean difference (95% confidence interval) of -0.06 mm Hg (-0.51, 0.39). Limits of agreement were -4.12 mm Hg to 4.00 mm Hg. Considering gradations of IAH defined by the World Society of the Abdominal Compartment Syndrome, CIAP was sensitive for detecting slightly elevated IAP (>11 mm Hg) but is less sensitive for distinguishing between higher grades of IAH (e.g., pressures >20 mm Hg or 25 mm Hg). Limits of agreement were best for patients with IAP less than 20 mm Hg, surgical or traumatic diagnoses and for patients with BMI less than 26.
Conclusions: Overall, CIAP is an accurate and simple means of measuring IAP when compared with the current standardized method. Elevated CIAP measurements should be confirmed with IIAP measurements if accurate grading is required until further validation and experience is obtained.