COLONIC LUMINAL PRESSURE IN HORSES WITH STRANGULATING AND NONSTRANGULATING OBSTRUCTION OF THE LARGE COLON

Colonic luminal pressure (median, range) measured during ventral midli ne celiotomy in 69 horses with strangulating obstruction (SO) of the l arge colon (SO; greater than or equal to 270 degrees large colon volvu lus; 27 cm H2O: 2 to 80 cm H2O) was greater (P =.0023) than that measu red in 37 horses with nonstrangulating obstruction (NSO) of the large colon (NSO; less than or equal to 1800 volvulus or a nonstrangulating displacement: 18 cm H2O; 6 to 46 cm H2O). Sixty-five percent (45 of 69 ) of horses with SO and all horses with NSO survived. Survival analysi s was restricted to 59 horses with large-colon SO that survived to hos pital discharge or met the criteria specified for classification as no nsurvivors. Colonic luminal pressure in nonsurvivors (48.5 cm H2O; 34 to 80 cm H2O) was higher (P = .0001) than that measured in survivors ( 18 cm H2O; 2 to 50 cm H2O) of SO. From response operating characterist ic curves, a luminal pressure of 38 cm H2O optimized the distribution of horses with SO into survivor and nonsurvivor groups. Sensitivity, s pecificity, and positive and negative predictive values for a colonic luminal pressure greater than 38 cm H2O in predicting nonsurvival were 0.89, 0.91. 0.72 and 0.97, respectively. Measurement of colonic lumin al pressure may be useful for predicting survival in horses with colon ic volvulus. (C) Copyright 1996 by The American College of Veterinary Surgeons