General anesthesia with an injectable 8% v/v sevoflurane lipid emulsion administered intravenously to dogs

Abstract

Objective: To evaluate the potential of an intravenous (IV) sevoflurane formulation for maintenance of general anesthesia in dogs. Study design: Prospective crossover design. Animals: Six healthy, mature, mixed-breed dogs, four males and two females, weighing 11.7 ± 3.4 kg. Methods: Anesthesia was induced and maintained with propofol IV for instrumentation. Baseline measurements were recorded before administration of either sevoflurane in oxygen (Sevo-Inh) or lipid-emulsified sevoflurane 8% v/v in 30% Intralipid IV (Sevo-E), 0.5 mL kg−1 over 5 minutes followed by an infusion at 0.1–0.3 mL kg−1 minute−1. Dogs were breathing spontaneously. The ‘up-and-down’ technique was used to determine the minimum alveolar concentration (MAC) of sevoflurane. Over 120 minutes, a tail clamp was applied every 15 minutes and sevoflurane administration was adjusted depending on the response. End-tidal sevoflurane concentration and variables were recorded at 30, 60, 90, and 120 minutes: heart rate (HR), systemic arterial pressure (sAP), respiratory rate (fR), end-tidal carbon dioxide tension, hemoglobin oxygen saturation (SaO2), arterial pH and blood gases, blood urea nitrogen, alanine aminotransferase, creatine kinase, gamma-glutamyl transferase, and aspartate aminotransferase. Results: There were no significant differences between treatments for HR, sAP, fR, SaO2, and biochemical variables (p > 0.05). pH and inline imagewere significantly decreased, and PaCO2 increased from baseline in Sevo-E (p < 0.05). MAC was significantly lower for Sevo-E than for Sevo-Inh, although the required dose of sevoflurane (g hour−1) to maintain general anesthesia was not significantly different between treatments. Conclusions and clinical relevance: Administration of 8% v/v sevoflurane lipid emulsion IV was effective in maintaining general anesthesia in dogs, but resulted in moderate cardiopulmonary depression, metabolic and respiratory acidosis. The amount of sevoflurane (g hour−1) required to maintain general anesthesia was significantly lower for inhaled than for IV sevoflurane.