In vitro validation of a novel methodfor continuous intra-abdominalpressure monitoring

Objective: Intra-abdominal pressure (IAP) measurement is important in daily clinical practice. Most measurement techniques vary in automaticity and reproducibility. This study tested a new fully automated continuous technique for IAP measurement, the CiMON. Methods: Three IAP measurement catheters (a Foley manometer and two balloon-tipped catheters) contained in a 50-ml infusion bag were placed on the bottom of a half open 3-l container. To simulate IAH the container was filled with water using 5 cmH(2)O increments (0-30 cmH(2)O). Pressure was estimated by observers using the Foley manometer (IAP(FM)) and simultaneously recorded using two IAP monitors: IAP(spie) with Spiegelberg and IAP(CiM) with CiMON. Observers were blinded to the reference levels. Fifteen observers (three intensivists, four residents, two medical students, and six nurses) conducted three pressure readings at each of the seven pressure levels with the FM technique, giving 315 readings. These were paired with the automated IAP(spie) and IAP(CiM) readings and the height of the H2O column. Results: The intra- and interobserver coefficients of variation (COVA) were low for all methods. There was no difference in the results between specialists, physicians in training, andnurses. Spearman's correlation coefficient (R-2) values for all paired measurements were greater than 0.9, and Bland-Altman analysis comparing the reference H2O column, IAP(FM), and IAP(spie) to IAP(CiM) showed a very good agreement at all pressure levels (bias -0.1+/-0.6 cmH(2)O, 95%CI -0.2 to 0). There was a consistent, low underestimation of the reference H2O pressure by the Spiegelberg technique and a low overestimation at pressures below 20 cmH(2)O by both other techniques. Conclusions: All three measurement techniques, IAP(FM), IAP(spie), and IAP(CiM) have good agreement with the applied hydrostatic pressure in this in vitro model of IAP measurement.