Comparison of Bladder Pressure Measurement by Using a Ruler and Transducer Monitor

Abstract

       Abdominal compartment syndrome (ACS) occurs when there is an increase intraabdominal pressure (IAP) to the point that it disturbs normal functioning of intra-abdominal hemorrhage and receive a large volume of intravenous fluid replacement and/or blood transfusion. The survival rate of those who have IAP under 25 cmH2O ranges from 17 to 75 percent. At present , there are two ways of measuring intra-abdominal pressure. The direct measurement is done by inserting a catheter connected with pressure transducer into the abdomen and the IAP value is shown in the monitor.

      However, this procedure is highly invasive and quite complicated to implement. The second and more commonly used method, first accomplished by Kron and colleagues in 1984, is indirect measurement of IAP which is done through the measurement of urinary bladder pressure. In this method, a Foley’s catheter is inserted into the bladder and connected with the pressure transducer through an infusion set and normal saline solution. IAP value is then shown on the monitor. Because of its simpler procedure and less invasive nature, the bladder pressure measurement has been recognized as a standard method of IAP measurement until present. However, not all healthcare settings have access to a pressure transducer particularly those non-intensive care units in developing countries.

      As a result, this prospective study was conducted to compare the IAP values obtained from a 3-tailed Foley’s catheter with a ruler to those measured by a pressured transducer. In this study a 3- tailed Foley’s catheter was inserted into the bladder. One tail drained urine into a urine bag and the other was connected to an infusion set with normal saline solution for bladder pressure measurement.

        Each pair of bladder pressure values were read from the ruler and pressure transducer for each time point (every 4-6 hours). A total of 29 pairs of bladder pressure values were obtained from two patients who had abdominal injuries. Data collection was done in a trauma intensive care unit of a tertiary care level hospital during October 2008 - March 2009. Data analyses were done using descriptive statistics, paired sample t-test and Pearson’s correlation. Results revealed that the average IAP values measured by the pressure transducer and a 3- tailed catheter with a ruler were not statistically significant and were highly correlated (p 0.124, t 1.586, Pearson’s r 0.915). Hence, it is concluded that a 3-taileld catheter with a ruler can be used in substitution of a pressure transducer in measuring intra-abdominal pressure. Further study should be done to investigate potential risks associated with the use of a 3-tailed catheter in measuring IAP such as the incidence of urinary infection.

Key words: intra-abdominal pressure, intra-abdominal hypertension, abdominal compartment syndrome, bladder pressure