Cardiopulmonary effects of propofol and a medetomidine-midazolam-ketamine combination in mallard ducks
Machin, K.L.; Caulkett, N.A.
American Journal of Veterinary Research 59(5): 598-602
1998
ISSN/ISBN: 0002-9645 PMID: 9582963 Document Number: 490232
Each of 12 healthy mallard ducks was anaesthetized twice in a crossover study design with 5 days between randomized treatments. Ducks were given medetomidine (50 micro g), midazolam (2 mg) and ketamine (10 mg) in combination, i.v., or propofol (10 mg, i.v., followed by 1- to 4-mg boluses). Systolic, diastolic and mean arterial pressures, heart and respiratory rates, and oesophageal temperature were recorded before anaesthesia and every 5 min after induction for 30 min, and at 5 min after reversal with atipamezole (250 micro g) and flumazenil (25 micro g; medetomidine-midazolam-ketamine, MMK, group) or last bolus (propofol group). Arterial blood samples from 8 ducks were collected before anaesthesia, 5, 10, 15, 30 min after induction, and after reversal or last bolus. Eight ducks survived the MMK anaesthesia; 1 duck died and 3 ducks required resuscitation to prevent death. All ducks survived propofol anaesthesia. Ducks anaesthetized with either anaesthetic agent had a significant increase in arterial carbon dioxide tension and decrease in arterial oxygen tension, arterial pH and oesophageal temperature. Ducks given MMK had a decrease in mean arterial pressure and respiratory rate, whereas ducks given propofol had an increase in respiratory rate. Rapid reversal of the effects of MMK was achieved with atipamezole and flumazenil. All physiological variables, except oesophageal temperature in the propofol group, returned to approximate baseline values after reversal or last bolus. It is concluded that it is unsafe to use MMK combination in ducks but that safe anaesthesia can be performed using propofol with appropriate monitoring and artificial ventilation.