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Effect of Hypercapnia or Xylazine on Lateral Ventricle and Lumbosacral Cerebrospinal Fluid Pressures in Pentobarbital‐anesthetized Horses
Author(s) -
MOORE RUSTIN M.,
TRIM CYNTHIA M.
Publication year - 1993
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.1993.tb01691.x
Subject(s) - xylazine , medicine , anesthesia , pentobarbital , cerebrospinal fluid pressure , ventricle , heart rate , blood pressure , lumbosacral joint , cardiology , intracranial pressure , anatomy , ketamine
Facial artery pressure, central venous pressure, heart rate, and lateral ventricle cerebrospinal fluid (CSF) pressure (LV‐CSFP) were measured in 10 pentobarbital‐anesthetized horses at arterial partial pressure of carbon dioxide (PaCO 2 ) values of 40,60, and 80 mm Hg, produced by varying the inspired carbon dioxide concentration. Variables were recorded at 5‐minute intervals for 15 minutes at each level of PaCO 2 . Arterial blood gas analysis was performed at the end of the 15‐minute time period for each level of PaCO 2 . Lateral ventricle CSF pressure was significantly increased (p < .05) at a PaCO 2 of 80 mm Hg. Cardiovascular variables were not significantly changed by changing PaCO 2 . The PaCO 2 was returned to 40 mm Hg; 1.1 mg xylazine/kg body weight was injected intravenously in eight horses, and data were collected for 60 minutes. No significant changes were observed. No changes were observed in two control horses not receiving xylazine. Subsequently, placement of a lumbosacral subarachnoid catheter allowed simultaneous measurement of LV‐CSFP and lumbosacral CSF pressure (LS‐CSFP) at PaCO 2 values of 40,60, and 80 mm Hg. The Pearson Correlation Coefficient between LV‐CSFP and LS‐CSFP was 0.94 (p < .0001) It was concluded that changes in CSF pressure could be detected at the lateral ventricle and the lumbosacral space; increasing PaCO 2 to 80 mm Hg resulted in significant increases in LV‐CSFP; xylazine does not increase LV‐CSFP in pentobarbital‐anesthetized, normocapnic horses; and under the conditions of this experiment, LV‐CSFP and LS‐CSFP were closely correlated.