Abstract
Twenty-six sea otters (Enhydra lutris) ages 6 months to 22 years under human care were immobilized with either intramuscular (IM) dexmedetomidine 0.0083±0.002 mg/kg, butorphanol 0.13±0.04 mg/kg, and midazolam 0.05 mg/kg (DBM; n=31) or medetomidine (mean±SD) 0.018±0.004 mg/kg, butorphanol 0.17±0.1 mg/kg, and midazolam 0.25±0.08 mg/kg (MBM; n=31) from 2009–2022 for various diagnostic, surgical, or preventive health procedures; records were retrospectively evaluated. For DBM and MBM, inductions were smooth and time from injection to working depth was (mean±SD) 16.4±5.2 minutes and 10.1±5.7 minutes, to intubation (65% of DBM and 66.7% of MBM procedures) was 24.2±6.0 minutes and 26±5.5 minutes, and to start of isoflurane or sevoflurane (65% of DBM and 61% of MBM procedures) was 25.5±6.8 minutes and 34.5±12 minutes, respectively. Induction parameters (DBM; MBM) recorded included heart rate (112±15.4 beats/minute; 104±13.7 beats/minute), respiratory rate (22.0±9.8 breaths/minute; 27.9±4.8 breaths/minute), ETCO2 (58.6±13.3 mm Hg; 64.7±11.6 mm Hg), pulse oximetry (96.8±3.4%; 96.8±2.9%), and rectal temperature (38.1±1.0°C; 37.4±0.7°C). For DBM, reversal with IM naltrexone (0.5–1.0 mg/mg butorphanol) and atipamezole (10 mg/mg dexmedetomidine) resulted in extubation at 5.0±1.8 minutes, standing at 10.2±3.9 minutes, and return to water at 19.0±4.4 minutes. For MBM, IM reversal with naltrexone (0.5–1.0 mg/mg butorphanol), flumazenil (0.01 mg/kg), and atipamezole (5 mg/mg medetomidine) resulted in extubation at 5.5±3.7 minutes and standing at 9±3.7 minutes. Complications were minor and included hypothermia (n=4, MBM; n=5, DBM), hyperthermia (n=6, DBM), vomiting (n=1; DBM), and renarcotization (n=3, MBM), which resolved after repeating a full dose of reversal agents. These protocols present an alternative to highly potent opioids, with smooth induction, excellent muscle relaxation, and consistent physiologic parameters.
*Presenting author
+Student presenter