Intra-abdominal pressure measurement: validation of intragastric pressure as a measure of intra-abdominal pressure

Background. The diagnosis of abdominal compartment syndrome depends upon the demonstration of an elevated intra-abdominal pressure (IAP). Direct measures of IAP are impractical in the critical care unit; intravesical pressure (IVP) and intragastric pressure (IGP) should represent acceptable surrogate measures. IVP is the preferred measure of IAP in critical care. We considered that IGP represents a practical alternative. The objective of this preliminary study was to observe the relationship between IGP and IAP. Methods. After Institutional Ethics Board approval, 29 patients having elective laparoscopic surgery were recruited. IAP was measured directly via the abdominal trochar. This was compared with IGP measured via a commercial balloon catheter placed into the stomach. Results. Measured IGP was always more positive than IAP; both showed linear correlation (r(2)> 0.9). When IGP was calibrated against IAP, an estimated difference between the IGP and IAP of +/- 2.5 mm Hg for 95% of the measurements was seen. Conclusions. The study demonstrates the strength of the relationship between IGP and IAP in normal individuals. Application of IGP measurement in the critical care patient is necessary to demonstrate its suitability for continuous IAP assessment.