Severe Hypoxemia in Muskoxen (Ovibos moschatus) Immobilized with Etorphine and Xylazine Corrected with Supplemental Nasal Oxygen

Abstract

Twenty-three muskoxen ( Ovibos moschatus ) housed in a captive facility for rewilding in Sweden were chemically immobilized for annual health evaluations and hoof trimming. The muskoxen were darted in May to September (2012-15) in their holding pen with etorphine (0.015 mg/kg) and xylazine (0.1 mg/kg) intramuscularly. Twenty-two of the 23 animals were immobilized with a single dart injection. The mean (SD) induction time was 4 (2) min. Arterial blood gases were collected from 18 animals. All animals were severely hypoxemic with varying degrees of respiratory acidosis. The hypoxemia resolved in 17 of 18 animals with intranasal oxygen supplementation at 1 L/min per 100 kg. Relative arterial oxygen saturation (SpO) measured by pulse oximetry was significantly higher than the arterial oxygen saturation calculated from the partial pressure of arterial oxygen (SaO) obtained by a blood gas analyzer. Based on these findings, muskox can be immobilized successfully with etorphine (0.015 mg/kg) and xylazine (0.1 mg/kg) but should receive supplemental oxygen.

Evaluation of Three Medetomidine-Based Anesthetic Protocols in Free-Ranging Wild Boars (Sus scrofa)

“…In this study, we corroborate previous findings (12,13,40) where the agreement between SaO 2 (iSTAT) and SpO 2 (pulse oximeter) was poor, particularly at low values of SpO 2 (Figures 1, 2). This could be due to several factors, including species-specific differences and to the use of alpha-2 adrenoceptor agonist drugs (41).…”

“…Both the respiratory acidosis and the hypercapnia occurred following the administration of the drug combinations in this study were mild and of limited clinical impact compared to other studies in anesthetized wildlife (12)(13)(14). This reflects the safety of such capture and drug combinations in regards to the respiratory and metabolic status in wild boars.…”

“…Pulse-oximeters are valuable tools for assessing oxygen saturation in immobilized wildlife, especially in field settings, where blood gas analysis is not routinely conducted. Nevertheless, the tendency of pulse oximeters to either underestimate or overestimate arterial oxyhemoglobin saturation and to lack in accuracy has been previously described in several mammalian species (12)(13)(14). Such inaccuracy requires that pulse oximetry is validated with the simultaneous use of a blood gas analyzer.…”

“…Such inaccuracy requires that pulse oximetry is validated with the simultaneous use of a blood gas analyzer. Most anesthetized wildlife require oxygen supplementation in order to correct hypoxemia (5,13), which could otherwise cause multiple organ dysfunction, including but not limiting to the central nervous system (15). Ultimately, such a physiological impact might also lead to biased results of the ecological studies dependent on capturing representative animals.…”

Intranasal oxygen reverses hypoxaemia in immobilised free-ranging capybaras (Hydrochoerus hydrochaeris)

“…Hypoxaemia is a concern during the chemical restraint of wild animals [ 13 ] as it can lead to myopathy and myocardial hypoxia [ 14 , 15 ]. Thus, oxygen (O 2 ) supplementation has been used to prevent or treat hypoxaemia during the immobilisation of wild animals [ 13 , 16 – 19 ]. Furthermore, chemical restraint protocols in capybaras have been based on dissociative anaesthesia (ketamine or tiletamine) in combination with other drugs (xylazine, romifidine, midazolam, zolazepam, levomepromazine, medetomidine, or dexmedetomidine) [ 7 – 12 ], and may be associated with muscle spasticity, nystagmus, disorientation, increased heart rate, and blood pressure [ 9 ].…”