Effects of glucose infusion on the endocrine, metabolic and cardiorespiratory responses to halothane anaesthesia of ponies.

The research article explores how glucose infusion during halothane anaesthesia affects the endocrine system, metabolism, and cardiorespiratory responses of ponies. Notably, findings suggest that glucose infusion may dampen the normal adrenal response to anaesthesia.

Study Design and Procedure

• The study was conducted on six ponies that were premedicated with acepromazine, a tranquilizer and anti-nausea drug. Anaesthesia was then induced with thiopentone, a rapid-onset short-acting barbiturate general anaesthetic, and maintained with halothane, a potent inhalational anaesthetic in oxygen, for two hours.
• Throughout this period, glucose was consistently infused into the ponies’ bloodstream intravenously with the intention to keep plasma glucose levels above 20 mmol/litre.

Outcomes and Observations

• The anaesthetic procedure led to hypothermia (reduced body temperature), a decrease in haematocrit (proportion of red blood cells in blood), hypotension (low blood pressure), hyperoxaemia (excess oxygen in the blood), and respiratory acidosis (a condition occurs when the lungs can’t remove enough of the carbon dioxide produced by the body).
• Synergistically, there was also an increase in plasma concentrations of lactate (a product of metabolism when oxygen levels drop), and arginine vasopressin (a hormone that helps retain water in the body and constricts blood vessels).
• The concentration of beta-endorphin, a hormone that has a significant role in pain perception, in plasma also increased transiently after 20 minutes. However, there were no changes recorded in the concentrations of adrenocorticotrophic hormone (a hormone that stimulates the adrenal glands), dynorphin (a type of protein that affects mood states), cortisol (a steroid hormone) or catecholamines (hormones made by your adrenal glands, like adrenaline).

Conclusion

• The data collected throughout this study suggested that infusing glucose into the ponies’ system during halothane anesthesia attenuated the typical adrenal response, which could potentially contribute to a smoother anaesthesia and recovery process. This finding hints at potential implications for anaesthetic procedures in veterinary medicine, especially for horses and ponies.