Comparison of a new device for the continuous intra-gastric measurement of intra-abdominal pressure (CiMon) with direct intra-peritoneal measurements in cirrhotic patients during paracentesis

Objective: To evaluate a new commercially available system for the intra-gastric measurement of intra-abdominal pressure (IAP). Design and setting: Prospective interventional trial in an intensive care unit of a university hospital. Patients: Ten patients with cirrhosis and tense ascites scheduled for paracentesis and instrumented with a ballon-tipped nasogastric tube. Intervention: Intermittent paracentesis with repeat paired measurements of IAP. Measurements and results: Intra-abdominal pressure was measured directly through the paracentesis catheter using a scaled measurement gauge. Simultaneously, intra-gastric measurements were performed with the CiMon device (Pulsion Medical Systems, Munich, Germany), by means of a ballon-tipped nasogastric tube connected to a pressure transducer. The range of IAP was 6.5-28 mmHg for direct measurements and 3.7-16 mmHg for measurements obtained with the CiMon device. The regression equation according to Passing and Bablok for the two methods had an intercept of 0.054 (95% CI-1.475-1.669) and a slope of 0.674 (95% CI 0.538-0.813). The cusum test showed a significant deviation from linearity (P < 0.05). In the Bland-Altman test bias and limits of agreement were - 4.9 (±6.8) mmHg or, expressed as percentage of the average, -44% (±49%). Conclusion: Intra-gastric measurments of IAP using the CiMon device were not reliable enough to be clinically useful in these ascitic patients.