Haemodynamic stability during general anaesthesia for intra-ocular surgery: the effect of topical oxybuprocaine

Local anaesthesia is frequently used in combination with light general anaesthesia to reduce the reflex responses to surgical stimulation. This combination has not previously been evaluated for intra-ocular surgery. During cataract extraction under general anaesthesia, the effect of topical anaesthesia with oxybuprocaine 0.4% on the pressor response was compared with normal saline in a control group. The simple technique of instilling local anaesthetic drops into the conjunctival sac blocked the pain pathway sufficiently to prevent the pressor response to surgical stimulation (p less than 0.001). Higher inspired concentrations of enflurane were required in the control group to achieve and maintain haemodynamic stability (p less than 0.001).