Metabolic and hormonal changes associated with arthroscopic surgery in the horse.

This study investigates how horses’ metabolic and hormonal levels change due to general anaesthesia and arthroscopic surgery. It found that general anesthesia in particular caused a temporary increase in blood sugar and insulin levels, and surgery led to minor increases in beta-endorphin and cortisol levels.

Study Details

• The research aimed to determine how general anesthesia and arthroscopic surgery affect horses’ metabolic and hormonal levels.
• Specifically, the elements researched were blood glucose, lactate, plasma non-esterified fatty acids, insulin, beta-endorphin, and cortisol. These are parameters that indicate stress in an organism and can convey its overall health status.
• The subjects of the study were seven horses.

Anaesthesia and Surgery procedure

• First, the horses were premedicated with xylazine, a sedative and muscle relaxant often used in veterinary medicine.
• Next, the anesthesia was induced with guaifenesin and sodium thiamylal. Guaifenesin is a muscle relaxant used in anesthesia for horses and sodium thiamylal is a barbiturate used to induce anesthesia.
• We maintained the anesthesia with halothane, a potent inhalation anesthetic, vaporized in oxygen.

Data Collection

• The researchers collected blood samples in the following stages: prior to surgery, during surgery, and after surgery.

Key Findings

• The initiation of anesthesia caused a temporary hyperglycaemia — an excessive amount of glucose in the bloodstream. This is due to the stress that the body undergoes during the anesthesia and surgery, which stimulates the release of glucose stored in the liver into the bloodstream.
• The induction of anesthesia was also associated with a significant increase in insulin levels in the blood. This is because insulin is responsible for the removal of excess glucose from the bloodstream.
• Once surgery began, insulin values fell but eventually spiked significantly after surgery.
• The surgery caused minor but notable increases in levels of beta-endorphin and cortisol. These are hormones linked to stress and pain, so an increase indicates that the body was undergoing stress during the surgery period.
• In the early post-operative period, beta-endorphin and cortisol levels had returned to their baseline values, showing that horses recovered quickly from the stress of surgery.
• No changes were recorded in blood lactate levels, which could suggest that horses did not undergo anaerobic metabolism during the period of surgery and anaesthesia.