The oculo-emetic reflex. A rationalisation of postophthalmic anaesthesia vomiting.

Data related to the incidence of postoperative vomiting were collected during prospective studies on 607 ophthalmic surgical patients of all ages who underwent halothane anaesthesia with spontaneous ventilation. Analysis of data in respect of age, sex and surgical site variables, and time of onset of vomiting, identified a female sex-related vomiting incidence of about 13% and a squint-related vomiting incidence of about 41%; no relationship between age and vomiting was identified. The analyses showed that squint surgery predisposed particularly to emesis, and was associated with a high incidence of both early and delayed vomiting. It is suggested that the apparent absence of an age-vomiting relationship in ocular, and especially squint, surgery, and the high incidence of vomiting, particularly the early vomiting associated only with squint surgery, provide clinical evidence for the existence of an oculo-emetic reflex. Our observations show that intra- and postoperative surgical stimulation of this oculo-emetic reflex is reflected in the incidences of vomiting after ocular surgery.