HEMODYNAMIC-EFFECTS OF EPIDURAL KETAMINE IN ISOFLURANE-ANESTHETIZED DOGS

Objective-The purpose of this study was to determine the hemodynamic e ffects of epidural ketamine administered during isoflurane anesthesia in dogs. Study Design-Prospective, single-dose trial. Animals-Six heal thy dogs (five males, one female) weighing 25.3 +/- 3.88 kg. Methods-O nce anesthesia was induced, dogs were maintained at 1.5 times the pred etermined, individual minimum alveolar concentration (MAC) of isoflura ne. Dogs were instrumented and allowed to stabilize for 30 minutes bef ore baseline measurements were recorded. Injection of 2 mg/kg of ketam ine in 1 mL saline/4.5 kg body weight was then performed at the lumbos acral epidural space. Hemodynamic data were recorded at 5, 10, 15, 20, 30, 45, 60, and 75 minutes after epidural ketamine injection. Statist ical analysis included an analysis of variance (ANOVA) for repeated me asures over time. All data were compared with baseline values. A P < . 05 was considered significant. Results-Baseline values +/- standard er ror of the mean (X +/- SEM) for heart rate, mean arterial pressure, me an pulmonary artery pressure, central venous pressure, pulmonary capil lary wedge pressure, cardiac index, stroke index, systemic vascular re sistance, pulmonary vascular resistance, and rate-pressure product wer e 108 +/- 6 beats/min, 85 +/- 10 mm Hg, 10 +/- 2 mm Hg, 3 +/- 1 mm Hg, 5 +/- 2 mm Hg, 2.3 +/- 0.3 L/min/m(2), 21.4 +/- 1.9 mL/beat/m(2), 338 6 +/- 350 dynes/sec/cm(5), 240 +/- 37 dynes/sec/cm(5), and 12376 +/- 1 988 beats/minXmm Hg. No significant differences were detected from bas eline values at any time after ketamine injection. Conclusions-The epi dural injection of 2 mg/kg of ketamine is associated with minimal hemo dynamic effects during isoflurane anesthesia. Clinical Relevance-These results suggest that if epidural ketamine is used for analgesia in do gs, it will induce minimal changes in cardiovascular function. (C) Cop yright 1997 by The American College of Veterinary Surgeons.