Perioperative plasma cortisol concentration in the horse.

This research examines the cortisol response of horses to anaesthesia and surgery, comparing responses between groups undergoing abdominal and non-abdominal surgeries. The study found a significant increase in cortisol levels in both groups during anaesthesia and surgery, with higher initial levels and a slower postoperative decline in the abdominal surgery group.

Comparing Cortisol Response in Different Surgical Groups

• The study aimed to investigate the cortisol response of horses to two types of surgery: abdominal and non-abdominal.
• An initial higher mean preoperative plasma cortisol concentration was observed in horses undergoing abdominal surgery. This suggests that these horses may have experienced greater physiological stress leading up to the procedure.

Changes in Cortisol Levels During Surgery

• In the non-abdominal group, the mean plasma cortisol concentration saw a significant increase from the preoperative mean, 30 minutes into surgery under halothane anaesthesia.
• In the abdominal group, there was a decrease in cortisol levels after induction of anaesthesia and surgical preparation. However, as surgery progressed, cortisol levels rose significantly.

Postoperative Cortisol Decline

• Following surgery, a large decline in mean cortisol concentrations occurred after 24 hours in the horses that underwent abdominal surgery.
• It took a relatively long time, about 60 hours, for the cortisol levels in this group to equal those of the horses in the non-abdominal group at 24 hours post-operation.
• This slower rate of decline could be indicative of the prolonged recovery associated with abdominal surgery, suggesting that these surgeries are more stressful for the horse, impacting cortisol levels for a longer period post-operation.