Neuroleptanalgesia for intraocular surgery.

INTRAOCULAR SURGERY is usually performed using a combination of heavy sedation and local nerve blocks. 1,2 Occasionally, hypotension and respiratory depression are severe enough to require active resuscitation with oxygen, analeptic drugs, and a vasopressor. Most of these patients are elderly and are not monitored during the operation. In a few centres, general anaesthesia is used. It carries several drawbacks: (a) the risk of postoperative nausea and vomiting and restlessness, (b) exposure to potent systemic agents, (c) increased intraocular pressure from possible coughing and bucking on the endotracheal tube, and (d) possible greater risk of iris prolapse and vitreous extrusion. The authors felt that a technique retaining the use of local anaesthesia but employing neuroleptanalgesia as an adjunct would provide optimum conditions. Monitoring of the patient was considered vital to the successful application of the method, Neuroleptanalgesia (NLA) and anaesthesia was originally submitted as an anaesthetic technique by Decastro and Mundeleer in 1959. a Since that time, thousands of patients have been sedated and anaesthetized by this method with moderate success. 4," A particular advantage cited has been the excellent tolerance by poor risk, geriatric patients, e In 1965, Tait and Tornetta reported the use of NLA for intraocular surgery. ~ They studied 35 patients undergoing cataract extraction and iridencleisis. They gave droperidol 10 mg. one hour preoperatively and Innovar~ 3-6 ml. in the operating room. They noted good analgesia for local anaesthetic injections and satisfactory sedation. In 1966, Wine reported the use of Innovar in 50 patients undergoing cataract extraction, s He was not impressed with the analgesia for the retrobulbar nerve block injection. There was a fairly high incidence of hypotension and respiratory depression. There was only intermittent monitoring of the patients in this study. In 1967, Cameron described the use of NLA in 19 patients undergoing cataract extraction. 9 He gave 5 rag. of droperidol 90 minutes preoperatively. In the operating room, phenoperidine in dosages of 1.0--2.5 mg. was given intravenously. No retrobulbar blocks were performed. In seven patients an analeptic was necessary to restore respiratory function. In this high dosage range, fentanyl was too potent a respiratory depressant to be used without ventilatory assistance.