Effect of patient positioning on intra-abdominal pressure monitoring

Background: Intra-abdominal hypertension affects multiple organ systems. Current measurement standard requires supine positioning, which jeopardizes patient safety by increasing the risk for ventilator-associated pneumonia. This study evaluated the relationship between intra-abdominal pressure (IAP) and head-of-bed (HOB) positioning in critically ill intubated patients. Methods: IAP measurements were performed using intravesical catheters with manometry. IAP was measured in a range of patient HOB increases from 0 degrees to 45 degrees. Multivariable generalized estimating equation modeling was performed to describe the relationship between IAP and HOB positioning. Results: Three hundred (300) observations were performed on 37 patients. In multivariable modeling, HOB increase was significantly associated with IAP. Body mass index, positive end-expiratory pressure, temperature, and diagnostic category were significant in this model, whereas age and Riker sedation score were not. Conclusions: There is a significant, positive association between IAP and HOB positioning in critically ill patients. Clinically relevant changes in IAP occur at HOB increases > 20 degrees. (c) 2007 Excerpta Medica Inc. All rights reserved.