Morphine administration in horses anaesthetized for upper respiratory tract surgery

The lower PaO2 in morphine recipients did not appear to be of clinical significance in healthy horses because the number of horses with a low PaO2 was similar between groups. The quality of recovery was significantly better in morphine recipients. These results indicate that morphine may be considered for use in clinical cases although further work is required to assess the analgesic properties of the drug in this species.