Droperidol: past present and future

Abstract

I am pleased to see that droperidol is to reappear amongst anaesthetists’ armamentarium; its loss was deeply felt [1]. Professor Sneyd discussed its antiemetic properties but only mentioned its original use in anaesthesia as a neuroleptic agent. In about 1970 the late Dr Peter Basket introduced me to the use of droperidol at a dose of 0.25–0.3 mg.kg−1. At this dose, marked alpha blocking effects were present and 500–1000 ml of colloid was required to restore blood pressure. At this dose, presumably derived from psychiatry, droperidol had the reputation of causing the sensation of ‘invisible chains’. The patient would lie serenely smiling for 6 h or more, but later questioning would reveal that they were in terrible pain or having terrible thoughts or worries. In my own practice, I gradually reduced the dose to 2.5 mg, and at this dose I could detect no clinical difference to a plain opioid plus N2O:O2 regimen. This dose resulted in smooth anaesthesia and good postoperative conditions (including day-cases). The neuroleptic technique was to administer then titrate an opioid, initially phenoperidine and later fentanyl. Top-ups were given to maintain the respiratory rate > 8 min−1. Accidental overdose was common; rates of three breaths.min−1 were not infrequently encountered. At that time ECG monitoring was rare; my department only owned one 8-cm ‘bouncing ball’ monitor and oxygen saturation monitoring relied on skin colour. The addition of 60% nitrous oxide rendered the patient anaesthetised without recall as long as the nitrous concentration was maintained and supplementary opioid given, using respiratory rate and pulse rate as a guide and patient movement as an imperative. Neuroleptanaesthesia was revelation in comparison to the standard O2:N2O:halothane combination, with rapid patient recovery and a clear head for the anaesthetist compared with working in an atmosphere of un-scavenged volatile anaesthetics. When ECG monitoring finally became routine I never detected changes related to the use of droperidol. Neuroleptanalgesia was eventually superseded by midazolam and patient controlled propofol sedation, but I found neuroleptanaesthesia difficult to replace after droperidol was withdrawn. With the advent of proper scavenging systems, sevoflurane and total intravenous anaesthesia I could replicate, if somewhat more expensively, the peri-operative conditions of neuroleptanaesthesia. Perhaps the time of neuroleptanaesthesia has passed in the affluent world but elsewhere it may still have a place.