REEVALUATION OF THE BALLOON IN GASTROINTESTINAL MANOMETRY

Although the flow-through catheter (FTC) system has been useful and sa tisfactorily accurate for gastrointestinal manometry, we hypothesized that a cylindrical, liquid-filled balloon would also accurately reflec t stress imposed by a sphincter. Latex balloons were fitted over the s ide ports of a closed-end catheter. The responses of the balloon and F TC system were compared in a cylindrical chamber commonly identified a s a Starling resistor. Independent, constant-pressure sources were use d to control both the inwardly directed ''contact pressure'' of the St arling resistor (P-s) and the intraluminal fluid pressure (P-lum). The balloon transducers responded linearly and accurately (slope = 1) to changes in both P-s and P-lum within the test range (0-200 mmHg, 0-26. 7 kPa). When either P-lum or P-s was held constant and the other chang ed, the balloon transducers always accurately measured the higher of t he two pressures. Although the performance of the FTC system was impro ved after the Starling resistor was lubricated, the FTC system sometim es responded inaccurately to changes in P-s. The ability of the balloo n transducers to measure the contractions of the lower esophageal sphi ncter and of the esophagus was demonstrated. We conclude that the ball oon transducer can measure sphincter pressure accurately and suggest t hat, in certain circumstances, it might be advantageous relative to th e FTC system.