Validation of the urine column measurement as an estimation of the intra-abdominal pressure

To evaluate the efficacy of the urine column (UC) measurement compared to the intra-vesicular pressure (IVP) measurement as an estimation of intra-abdominal pressure (IAP) in patients with IAP up to 30 mmHg.

Fifteen patients undergoing a laparoscopic cholecystectomy were studied. All patients were catheterized. IVP measurements were performed using a pressure transducer connected to the culture aspiration port. UC measurements were done by holding up the tubing against a measuring rod. The symphysis pubis was used as the zero-reference. IAP was raised from 0 to 30 mmHg using increments of 5 mmHg, during which first the IVP and then UC measurement series were recorded end-expiratory. Fifty and 100 ml of saline were used as a priming volume.

The IVP and UC measurements showed a significant correlation with IAP. Comparing IVP and UC showed a correlation of 0.91 (p < 0.001) for 50 ml and 0.87 (p < 0.001) for 100 ml of saline as a priming volume. Using 50 ml of saline, UC was 0.68 mmHg higher than IVP (95% CI -7.21 to +5.85 mmHg). For 100 ml of saline, UC was 1.23 mmHg lower than IVP (95% CI -7.41 to +9.87 mmHg).

UC measurement shows significant correlation to IVP measurement as an estimation of the IAP. Further study needs to be done to conclude whether UC measurement is a reliable clinical alternative to IVP measurement.