Oxygen supplementation before induction of general anaesthesia in horses.

This research article investigates the effect of oxygen supplementation prior to general anaesthesia induction in horses. The study found that the practice increased the arterial partial pressure of oxygen in the immediate aftermath of induction, suggesting the technique could be beneficial.

Objective and Methodology:

• The main objective of this research was to determine whether the administration of oxygen at a rate of 15 l/min for three minutes via a nasal cannula before general anaesthesia induction in horses could increase the arterial partial pressure of oxygen (PaO) immediately after induction.
• The study utilized a randomised, prospective clinical trial design, involving eighteen adult horses (classified as American Society of Anesthesiologists physical status 1 or 2) undergoing elective anaesthesia.
• The horses were randomly divided into two groups: a control group that received no oxygen supplementation before anaesthesia induction, and an oxygen group that did receive supplementation.
• All horses were anaesthetised using intravenous detomidine, butorphanol, ketamine, midazolam, and isoflurane. Arterial blood samples were taken immediately after induction (T = 0) and 30 minutes later (T = 30) to perform blood gas analysis.

Results:

• The study found a significantly higher PaO in the oxygen group than the control group (11.0 ± 2.6 kPa vs. 7.4 ± 1.6 kPa; mean ± s.d., P = 0.005) at the time of induction (T=0). However, no significant differences were noted between the two groups at 30 minutes after induction (T = 30).
• The partial pressure of carbon dioxide (PaCO ) and the intrapulmonary shunt fraction (Qs/Qt) did not show any significant difference between the groups.

Conclusions:

• Supplementing oxygen using a nasal cannula prior to induction of general anaesthesia in horses is practical and effectively boosts the PaO immediately after induction.
• There is a need for further research to explore whether oxygen supplementation prior to anaesthesia induction could influence outcomes in equine anaesthesia.