INHALANT ANESTHETIC RECOVERY FOLLOWING INTRAMUSCULAR EPINEPHRINE IN THE LOGGERHEAD SEA TURTLE ( CARETTA CARETTA)

Abstract

Prolonged anesthetic recovery time is a common complication of chelonian inhalant anesthesia and may be exacerbated by right-to-left intracardiac shunting of blood. Epinephrine may decrease intracardiac shunting, which may shorten anesthetic recovery time. The study objective was to assess inhalant anesthetic recovery time following intramuscular epinephrine compared with saline in the loggerhead sea turtle ( Caretta caretta). With the use of a prospective, randomized, blinded, crossover design with a 1-wk washout period, six turtles were anesthetized with intravenous (IV) alfaxalone 3 mg/kg, orotracheally intubated, manually ventilated with 3.5% isoflurane inhalant in 100% oxygen for 90 min, and administered either intramuscular (IM) epinephrine 0.1 mg/kg or IM saline 0.1 ml/kg. Isoflurane administration was immediately discontinued and turtles were manually ventilated with room air until extubation. Physiologic variables, sedation scores, end-tidal carbon dioxide (ET_CO2) and isoflurane (ET_ISO) concentrations, time to first movement, and time to extubation were recorded and two-time-point venous blood gas analyses performed. Data were compared with the use of paired t-tests and repeated-measures analyses of variance (ANOVA) ( P < 0.05). No morbidity, mortality, or adverse events occurred. ET_CO2 and ET_ISO did not significantly change over time during the isoflurane delivery period ( P = 0.990). Mean time to first movement was significantly faster following epinephrine (69.24 ± 12.28 min) compared with saline (87.71 ± 27.05 min, P = 0.047). Although differences were not statistically significant ( P = 0.133), time to extubation was at least 30 min faster (31-123 min) in 4/6 turtles following epinephrine compared with saline. Intramuscular epinephrine significantly reduces time to first movement during isoflurane anesthetic recovery in loggerhead sea turtles.

Keywords: Anesthesia; Caretta caretta; epinephrine; inhalant; recovery; sea turtle.