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Haw, A.; Hofmeyr, M.; Fuller, A.; Buss, P.; Miller, M.; Fleming, G.; Meyer, L., 2014. Butorphanol with oxygen insufflation corrects etorphine-induced hypoxaemia in chemically immobilized white rhinoceros (Ceratotherium simum). BMC Veterinary Research 10(253): 1-9

Location: Africa
Subject: Diseases
Species: White Rhino

Original text on this topic:


Opioid-induced immobilization is associated with severe respiratory depression in the white rhinoceros. We evaluated the efficacy of butorphanol and oxygen insufflation in alleviating opioid-induced respiratory depression in eight boma-managed rhinoceros.


Chemical immobilization with etorphine, azaperone and hyaluronidase, as per standard procedure for the white rhinoceros, caused severe respiratory depression with hypoxaemia (PaO2&#8201;=&#8201;27&#8201;±&#8201;7 mmHg [mean&#8201;±&#8201;SD]), hypercapnia (PaCO2&#8201;=&#8201;82&#8201;±&#8201;6 mmHg) and acidosis (pH =7.26&#8201;±&#8201;0.02) in the control trial at 5 min. Compared to pre-intervention values, butorphanol administration (without oxygen) improved the PaO2 (60&#8201;±&#8201;3 mmHg, F(3,21) =151.9, p <0.001), PaCO2 (67&#8201;±&#8201;4 mmHg, F(3,21) =22.57, p <0.001) and pH (7.31&#8201;±&#8201;0.06, F(3,21) =27.60, p <0.001), while oxygen insufflation alone exacerbated the hypercapnia (123&#8201;±&#8201;20 mmHg, F(3,21) =50.13, p <0.001) and acidosis (7.12&#8201;±&#8201;0.07, F(3,21) =110.6, p <0.001). Surprisingly, butorphanol combined with oxygen fully corrected the opioid-induced hypoxaemia (PaO2&#8201;=&#8201;155&#8201;±&#8201;53 mmHg) and reduced the hypercapnia over the whole immobilization period (p <0.05, areas under the curves) compared to the control trial. However, this intervention (butorphanol&#8201;+&#8201;oxygen) did not have any effect on the arterial pH.


Oxygen insufflation combined with a single intravenous dose of butorphanol improved the immobilization quality of boma-managed white rhinoceros by correcting the opioid-induced hypoxaemia, but did not completely reverse all components of respiratory depression. The efficacy of this intervention in reducing respiratory depression in field-captured animals remains to be determined.

Anaesthesia; Hypoxia; Hypercapnia; Acidaemia; Blood gases; Opioids; Partial-opioid antagonist

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