Effects of lumbosacral subarachnoid catheterization in horses.

Objectives-To evaluate the effects of long duration subarachnoid catheterization in horses on cerebrospinal fluid (CSF) cellularity and bacteriology, arterial blood pressure, heart rate, respiratory rate, rectal body temperature, and spontaneous locomotor activity. Study Design-Prospective experimental study. Animal -Five clinically normal healthy adults horses weighing 511 +/- 47 kg. Methods-Subarachnoid catheters were placed using sedation and local anesthesia and maintained for 48 hours in standing horses. Cerebrospinal fluid samples were tested for cellularity and bacteria growth. Heart rate, respiratory rate, arterial blood pressure, and body temperature were recorded. Locomotor activity was graded. One-way repeated measures ANOVA and Bonferroni's test were used to statistically compare data from baseline to 12, 24, and 48 hours. Results-Subarachnoid catheterization in horses produced an acute inflammatory reaction after 12 hours of catheterization, as evidenced by a statistically significant increase in CSF white blood cell count. No bacterial contamination was encountered. No significant differences were found in heart rate, respiratory rate, body temperature, and arterial blood pressure. The horses did not develop motor ataxia or proprioceptive deficits during 48 hours of catheterization. Conclusions-Results of this study suggest that 48 hours of subarachnoid catheterization in horses does not produce clinical signs of neurologic dysfunction or cardiovascular and respiratory changes, even though an inflammatory reaction occurred. Clinical Relevance-Subarachnoid catheterization in horses is preferred for monitoring CSF pressure or for repeated collection. Understanding the effects of catheterization alone, allows the clinician to better interpret abnormalities in CSF collected. (C) Copyright 1999 by The American College of Veterinary Surgeons.