Effect of a short pre-anesthetic fast on arterial blood gas values in isoflurane-anesthetized donkeys.

This study compared arterial blood gas parameters in anesthetized adult donkeys after a 5-hour fast ( n = 22) or no fast ( n = 21). Donkeys were premedicated with xylazine, induced to anesthesia with ketamine and diazepam or midazolam, and maintained with isoflurane in oxygen while breathing spontaneously and positioned in lateral recumbency. Sampling occurred approximately 25 minutes after induction. Arterial pH, bicarbonate concentration, and base excess were higher in fasted donkeys compared to unfasted donkeys. There were no differences in partial pressure of arterial oxygen, partial pressure of arterial carbon dioxide, or arterial lactate concentrations. No advantages of a short pre-anesthetic fast were identified.