Use of thiafentanil-medetomidine for the induction of anesthesia in emus (Dromaius novaehollandiae) within a wild animal park.

Fifteen adult emu (Dromaius novaehollandiae) anesthetic events were successfully undertaken with the use of thiafentanil oxalate (A3080) 0.175 mg/kg i.m. (SD 0.026) and medetomidine 0.092 mg/kg i.m. (SD 0.009) via remote injection. Following induction, the birds were transported to the clinic, where a venous blood gas sample was taken for analysis, which indicated a respiratory acidosis, with a mean arterial pCO2 of 54.46 mmHg (SD 9.31) and venous pH of 7.135 (SD 0.11), most likely due to moderate bradypnoea. Atipamezole 0.2 mg/kg i.v. (SD 0.02) was administered, immediately followed by orotracheal intubation initiating 2-3% isoflurane with 2 L/min oxygen flow. Parameters evaluated during anesthesia included heart rate, respiratory rate, anesthetic depth, and electrocardiogram readings. Physical exams plus any required procedures were performed in addition to venous blood samples for biochemistry and full blood counts. The birds were then recovered in a crate padded with grass hay with administration of 8.75 mg/kg (SD 1.36) naltrexone (50 mg/mg A3080) administered in equal doses i.v. and i.m. along with 5 mg midazolam i.m. to reduce excitement. Emus were placed in a lateral position and given 4 L/min oxygen via the endotracheal tube, until movement of the head and neck necessitated extubation. Recovery was rapid and smooth in each case with a mean time of 3.1 min from antagonist administration to sternal recovery. On the basis of rapid, smooth, and successful inductions and recoveries, the described dosage of thiafentanil and medetomidine, with administration of midazolam prior to recovery, is recommended for immobilization of adult emus. Due to evidence of respiratory acidosis and bradypnoea, careful monitoring should be instituted throughout and oxygen provision recommended from initial contact.