Journal Articles
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Item Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum)(African Online Scientific Information Systems (Pty) Ltd t/a AOSIS, 2018-10-18) Meyer LCR; Fuller A; Hofmeyr M; Buss P; Miller M; Haw AOpioid-induced immobilisation results in severe respiratory impairment in the white rhinoceros. It has therefore been attempted in the field to reverse this impairment with the use of opioid agonist-antagonists, such as nalorphine, nalbuphine, butorphanol and diprenorphine; however, the efficacy of some of these treatments has yet to be determined. The efficacy of butorphanol, either alone or in combination with diprenorphine both with and without oxygen insufflation, in alleviating opioid-induced respiratory impairment was evaluated. The study was performed in two parts: a boma trial and a field trial. Rhinoceroses were immobilised specifically for the study, according to a strict protocol to minimise confounding variables. A two-way analysis of variance was used to compare the physiological responses of the rhinoceroses to the different treatments and their effects over time. The intravenous administration of butorphanol (at 3.3 mg per mg etorphine) plus diprenorphine (at 0.4 mg per mg etorphine) did not offer any advantage over butorphanol (at 15 mg per mg etorphine) alone with regard to improving PaO2, PaCO2 and respiratory rates in etorphine-immobilised white rhinoceroses. Both butorphanol + diprenorphine + oxygen and butorphanol + oxygen, at the doses used, significantly improved the etorphine-induced hypoxaemia in both boma- and field-immobilised white rhinoceroses. Clinically acceptable oxygenation in field-immobilised white rhinoceroses can be achieved by using either treatment regimen, provided that it is combined with oxygen insufflation.Item Chemical immobilisation of lions: weighing up drug effectiveness versus clinical effects(Medpharm Publications on behalf of the South African Veterinary Association, 2023-06-01) Donaldson AC; Fuller A; Meyer LCR; Buss PESelection of an effective drug combination to immobilise African lions (Panthera leo) requires balancing immobilisation effectiveness with potential side effects. We compared the immobilisation effectiveness and changes to physiological variables induced by three drug combinations used for free-ranging African lions. The lions (12 animals per drug combination) were immobilised with tiletamine-zolazepam-medetomidine (TZM), ketamine-medetomidine (KM) or ketamine-butorphanol-medetomidine (KBM). Induction, immobilisation, and recovery were timed, evaluated using a scoring system, and physiological variables were monitored. The drugs used for immobilisation were antagonised with atipamezole and naltrexone. The quality of induction was rated as excellent for all drug combinations and induction times (mean ± SD) did not differ between the groups (10.54 ± 2.67 min for TZM, 10.49 ± 2.63 min for KM, and 11.11 ± 2.91 min for KBM). Immobilisation depth was similar over the immobilisation period in the TZM and KBM groups, and initially light, progressing to deeper in lions administered KM. Heart rate, respiratory rate and peripheral arterial haemoglobin saturation with oxygen were within the expected range for healthy, awake lions in all groups. All lions were severely hypertensive and hyperthermic throughout the immobilisation. Following antagonism of immobilising drugs, lions immobilised with KM and KBM recovered to walking sooner than those immobilised with TZM, at 15.29 ± 10.68 min, 10.88 ± 4.29 min and 29.73 ± 14.46 min, respectively. Only one lion in the KBM group exhibited ataxia during recovery compared to five and four lions in the TZM and KM groups, respectively. All three drug combinations provided smooth inductions and effective immobilisations but resulted in hypertension. KBM had an advantage of allowing for shorter, less ataxic recoveries.Item Effects of three immobilizing drug combinations on ventilation, gas exchange and metabolism in free-living African lions (Panthera leo)(Oxford University Press and the Society for Experimental Biology, 2023-08-10) Donaldson AC; Buss PE; Fuller A; Meyer LCR; Cooke SJFree-living lions (12 per group) were immobilized with tiletamine-zolazepam-medetomidine (TZM), ketamine-medetomidine (KM), or ketamine-butorphanol-medetomidine (KBM). During immobilization, respiratory, blood gas and acid-base variables were monitored for 30 minutes. Respiratory rates were within expected ranges and remained constant throughout the immobilizations. Ventilation increased in lions over the immobilization period from 27.2 ± 9.5 to 35.1 ± 25.4 L/min (TZM), 26.1 ± 14.3 to 28.4 ± 18.4 L/min (KM) and 23.2 ± 10.8 to 26.7 ± 14.2 L/min (KBM). Tidal volume increased over the immobilization period from 1800 ± 710 to 2380 ± 1930 mL/breath (TZM), 1580 ± 470 to 1640 ± 500 mL/breath (KM) and 1600 ± 730 to 1820 ± 880 mL/breath (KBM). Carbon dioxide production was initially lower in KBM (0.4 ± 0.2 L/min) than in TZM (0.5 ± 0.2 L/min) lions but increased over time in all groups. Oxygen consumption was 0.6 ± 0.2 L/min (TZM), 0.5 ± 0.2 L/min (KM) and 0.5 ± 0.2 L/min (KBM) and remained constant throughout the immobilization period. Initially the partial pressure of arterial oxygen was lower in KBM (74.0 ± 7.8 mmHg) than in TZM (78.5 ± 4.7 mmHg) lions, but increased to within expected range in all groups over time. The partial pressure of arterial carbon dioxide was higher throughout the immobilizations in KBM (34.5 ± 4.2 mmHg) than in TZM (32.6 ± 2.2 mmHg) and KM (32.6 ± 3.8 mmHg) lions. Alveolar-arterial gradients were initially elevated, but decreased over time for all groups, although in KM lions it remained elevated (26.9 ± 10.4 mmHg) above the expected normal. Overall, all three drug combinations caused minor respiratory and metabolic side-effects in the immobilized lions. However, initially hypoxaemia occurred as the drug combinations, and possibly the stress induced by the immobilization procedure, hinder alveoli oxygen gas exchange.
