Haw, AnnaHofmeyr, MarkusFuller, AndreaBuss, Peter ErikMiller, MicheleFleming, GregoryMeyer, Leith Carl Rodney2015-02-202015-02-202014-10Haw, 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, vol. 10, no. 253, pp. 1-9.1746-6148 (print)10.1186/s12917-014-0253-0http://hdl.handle.net/2263/43736BACKGROUND : 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. RESULTS : Chemical immobilization with etorphine, azaperone and hyaluronidase, as per standard procedure for the white rhinoceros, caused severe respiratory depression with hypoxaemia (PaO2 = 27 ± 7 mmHg [mean ± SD]), hypercapnia (PaCO2 = 82 ± 6 mmHg) and acidosis (pH =7.26 ± 0.02) in the control trial at 5 min. Compared to pre-intervention values, butorphanol administration (without oxygen) improved the PaO2 (60 ± 3 mmHg, F(3,21) =151.9, p <0.001), PaCO2 (67 ± 4 mmHg, F(3,21) =22.57, p <0.001) and pH (7.31 ± 0.06, F(3,21) =27.60, p <0.001), while oxygen insufflation alone exacerbated the hypercapnia (123 ± 20 mmHg, F(3,21) =50.13, p <0.001) and acidosis (7.12 ± 0.07, F(3,21) =110.6, p <0.001). Surprisingly, butorphanol combined with oxygen fully corrected the opioid-induced hypoxaemia (PaO2 = 155 ± 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 + oxygen) did not have any effect on the arterial pH. CONCLUSIONS : 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.en© 2014 Haw et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0).AnaesthesiaHypoxiaHypercapniaAcidaemiaBlood gasesOpioidsPartial-opioid antagonistArticle