Effects of midazolam on corticosterone and blood gases in spectacled eiders prior to transmitter implantation

Journal of Wildlife Management
By: , and 



Stress and physical exertion may affect the physiology and behavior of wildlife during and after capture, and consequently, survival following release. Such effects may reduce the quality and quantity of the data obtained from captured wildlife. We captured spectacled eiders (Somateria fischeri), a species listed as threatened under the United States Endangered Species Act, in western Alaska, USA, during spring 2018 for surgical implantation of satellite transmitters. We evaluated the efficacy of midazolam, a benzodiazepine sedative given at capture, to reduce stress and physical exertion. We dosed spectacled eiders with either midazolam (5 mg/ml, urn:x-wiley:0022541X:media:jwmg22046:jwmg22046-math-0001 = 2.2 mg/kg intramuscular; n = 20) or saline (0.7 ml intramuscular; n = 20) at the point of capture. We assessed sedation level and collected blood samples upon arrival to the field surgery site and at anesthetic induction. We found that midazolam reduced mean corticosterone concentration by 29% and median lactate concentration by 30.3% at the mean arrival time (42 min post‐dosing) relative to the control group. These effects had abated by the mean induction time (99 min post‐dosing). Unexpectedly, blood pH was reduced in the midazolam treatment relative to controls at both arrival and induction, which likely resulted from sedative‐induced respiratory depression that was easily treated with intubation and mechanical ventilation, and administration of the reversal drug, flumazenil. Low blood pH was not associated with negative post‐surgical outcomes, as had been found in spectacled eiders with acidosis caused by anaerobic metabolism typical of physical exertion. Intramuscular injection of midazolam in the field effectively reduced stress and physical exertion in spectacled eiders prior to surgical implantation of transmitters. © 2021 The Wildlife Society.

Publication type Article
Publication Subtype Journal Article
Title Effects of midazolam on corticosterone and blood gases in spectacled eiders prior to transmitter implantation
Series title Journal of Wildlife Management
DOI 10.1002/jwmg.22046
Volume 85
Issue 5
Year Published 2021
Language English
Publisher The Wildlife Society
Contributing office(s) Alaska Science Center Biology WTEB
Description 11 p.
First page 909
Last page 919
Google Analytic Metrics Metrics page
Additional publication details