The effects of volume and speed of injection in peribulbar anaesthesia

We have evaluated the effects of the volume and speed of administration of local anaesthetic during peribulbar anaesthesia. One hundred and forty patients scheduled for cataract surgery were randomly allocated to one of four groups of 35. Each patient received an injection of the same mixture of lignocaine, bupivacaine and hyaluronidase. Patients in group A were given 9 ml at a speed of 5 ml.min-1, group B were given the same volume at 12 ml.min-1, group C were given 13.5 ml at 5 ml.min-1 and group D were given 13.5 ml at 12 ml.min-1. A significantly higher incidence of satisfactory akinesia was found in group D, whose pain score at injection was no higher than for the other groups. Large volumes of local anaesthetic significantly affected intra-ocular pressure. The incidences of early and late ptosis or diplopia were not affected by either the rate of injection or the volume of local anaesthetic.