Postinduction butorphanol administration alters oxygen consumption to improve blood gases in etorphine-immobilized white rhinoceros

Abstract

Hypoxaemia and hypercapnia in etorphine-immobilized rhinoceros resulted from an increased [ [Formula: see text] ] and increased [Formula: see text] and [Formula: see text] associated with muscle tremors. Rather than being associated with changes in V˙e, it appears that improved blood gases following butorphanol administration were a consequence of decreased [Formula: see text] associated with reduced muscle tremoring.

Midazolam Alters Acid-Base Status Less than Azaperone during the Capture and Transport of Southern White Rhinoceroses (Ceratotherium simum simum)

“…Increases in PCO 2 are indicative of impaired alveolar ventilation and are thought to be the result of respiratory neuronal depression [ 39 ] and thoracic muscular rigidity [ 20 ] caused by the etorphine. Ventilation-perfusion mismatching and shunting during prolonged lateral recumbency likely contributed to the hypercarbia in our animals [ 40 ] together with increased carbon dioxide production from etorphine-induced hyper-metabolism [ 19 ]. By the start of transport venous PCO 2 had decreased to normal values [ 33 ], which were maintained throughout the journey.…”

“…The limitation of this approach is that accuracy can only be assumed if plasma protein and electrolyte concentrations are within normal limits [ 17 ]. White rhinoceroses captured with etorphine experience significant physiological disturbances resulting from the effects of the potent opioid combined with a fight or flight response [ 18 , 19 ]. These disturbances include hypoxemia, hypercapnia, tachycardia and systemic hypertension [ 18 ].…”

Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum)

“…One possible limitation of the study is that the But+M5050+O 2 group had a smaller sample size than that of the But+O 2 group. Another possible explanation could be that when butorphanol+diprenorphine is used in the field, compared to butorphanol alone, the lower dose of butorphanol or the differing antagonist effects of diprenorphine in this combination may have a better effect on antagonising other pathophysiological effects of etorphine that cause hypoxaemia (Buss et al 2018 ; Meyer et al 2015 ), with less of an effect on ventilation or the production of carbon dioxide from metabolism.…”

Do potent immobilising-opioids induce different physiological effects in impala and blesbok?

“…Vasoconstriction could have also caused a faster blood flow which might have hindered gas exchange, as capillary blood might have passed the alveoli too fast to enable effective oxygen diffusion (Hattingh et al 1994 ; Meyer et al 2015 ). Furthermore, opioid-induced hypermetabolism (Buss et al 2018 ) may have increased systemic oxygen extraction which possibly could have also increased the A-a gradient.…”

“…Initially elevated lactate in the impala could have been associated with an initial exaggerated stress response of these animals to the capture procedure. A stress response would lead to an increased metabolism and therefore increase the oxygen demand, further compounding the hypoxaemia (Buss et al 2018 ). The assumption that impala not only suffered from hypoxaemia due to opioid-induced respiratory compromise but also experienced a stress response is supported by the elevated glucose and an initially raised heart rate (Hattingh 1988 ).…”