Using Our Eyes: Can Intraoperative Problems Be Detected Early Enough?

One aim of the anaesthetist should be to ensure that the horse they anaesthetise recovers from anaesthesia in the same or better ‘condition’ than they were in before anaesthesia was induced. The main problems that concern us during anaesthesia are; is the horse too deep? Is the horse too light? Is the physiological status of the horse deteriorating?

Monitoring central nervous system (CNS) function during anaesthesia in the horse is a fundamental skill. This is for 2 reasons; firstly horses are incredibly sensitive to the cardiovascular and respiratory depressant effects of the inhaled anaesthetic agents and excessively deeply anaesthetised horses may have dangerously compromised physiology. Secondly, under inhaled anaesthesia, changes in anaesthetic depth are normally slow but if the horse reaches the threshold where sensory input permeates through anaesthesia to cause the horse to react purposefully, the reaction of the horse can be rapid, violent and dangerous to the horse, equipment and theatre personnel. [...]