Changes in the acid base status of sheep anaesthetised with a combination of atropine sulphate acepromazine and ketamine hydrochloride.

pH, PaCO2, PaO2, standard bicarbonate, base excess and reduced pH were measured in sheep before and at regular intervals after administration of ketamine with and without atropine and acepromazine premedication. A decrease in pH and PaO2 and a rise in PaCO2 was observed 15 minutes after administration of ketamine. Administration of atropine with and without acepromazine had no significant effect on pH, PaCO2 and PaO2. The values for standard bicarbonate, base excess and reduced pH were not significantly affected. This indicates that minor changes observed in pH, PaCO2 after ketamine administration are compensated for by the healthy animal's blood buffer system.