Direct Measurement of Intra-abdominal Pressures in a Horse by Using a Solid Microsensor

Current techniques to measure intra-abdominal pressures in horses use metal cannulas. Concerns that the metal cannula could puncture abdominal viscera if left in place prevent continual pressure measurements. The aim of this study was to validate the use of a solid microsensor and digital monitoring system in the measurement of direct intra-abdominal pressure in horses by comparing its values with the ones simultaneously obtained by means of an intraperitoneal cannula. Ten healthy adult horses had intra-abdominal pressures measured simultaneously through an intraperitoneal cannula zeroed midway between the height of the tuber ishii and point of the shoulder and by the use of an intraperitoneal solid microsensor placed within the abdomen at the same level as the metal cannula. Three repeated intra-abdominal pressure measurements were obtained at rest, after placement of a nasogastric tube, and after placement of 5-L increments of water into the stomach, up to a total volume of 20 L of water. The difference between values obtained (after conversion) was 3.6 mm Hg. The correlation coefficient was 0.825. Direct intra-abdominal pressure monitoring with a solid microsensor allows continuous monitoring without concern for gastrointestinal perforation, is simple to use and to calibrate, and is minimally invasive.