title: Butorphanol with oxygen insufflation corrects etorphine-induced hypoxaemia in chemically immobilized white rhinoceros (Ceratotherium simum).
abstract: BACKGROUND
  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.
authors.forename: Anna
authors.initials: A
authors.lastname: Haw
authors.forename: Markus
authors.initials: M
authors.lastname: Hofmeyr
authors.forename: Andrea
authors.initials: A
authors.lastname: Fuller
authors.forename: Peter
authors.initials: P
authors.lastname: Buss
authors.forename: Michele
authors.initials: M
authors.lastname: Miller
authors.forename: Gregory
authors.initials: G
authors.lastname: Fleming
authors.forename: Leith
authors.initials: L
authors.lastname: Meyer
mesh_terms: D000818:Animals; D001376:Azaperone / Q000008:administration & dosage / Q000494:pharmacology; D002077:Butorphanol / Q000008:administration & dosage / Q000627:therapeutic use*; D002245:Carbon Dioxide / Q000097:blood; D005048:Etorphine / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D006821:Hyaluronoglucosaminidase / Q000008:administration & dosage / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000139:chemically induced / Q000188:drug therapy / Q000662:veterinary*; D007103:Immobilization / Q000662:veterinary*; D008297:Male; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D010313:Partial Pressure; D010527:Perissodactyla
chemical_list: D002245:Carbon Dioxide; D001376:Azaperone; D005048:Etorphine; D006821:Hyaluronoglucosaminidase; D002077:Butorphanol; D010100:Oxygen