Physostigmine and anaesthesia emergence delirium in preschool children: a randomized blinded trial

A significant proportion of preschool children experiences severe emergence agitation after anaesthesia. The symptoms of disorientation, restlessness, inconsolable crying and thrashing resemble an acute psychosis similar to an agitated central anticholinergic syndrome. The primary aim of this randomized controlled study was to assess the efficiency of the cholinesterase-inhibitor physostigmine in these children and to identify adverse effects.

We anaesthetized 211 children (1-5 yr) with sevoflurane after midazolam premedication for varying operative procedures. Multimodal intraoperative and prophylactic pain therapy combined alfentanil, piritramide, diclofenac and regional/local bupivacaine. A 5-step score assessed emergence agitation. Severely agitated children were treated immediately with physostigmine (30 mug kg-1) or placebo in a randomized, double-blind fashion. The primary variable was the agitation score after 5 min.

Severe delirium occurred in 19% of all children. Five minutes following injection, severe agitation was still present in 10 out of 20 patients treated with physostigmine and 16/20 with placebo. This difference did not reach statistical significance (P = 0.1). Rescue therapy with intravenous propofol was given after 15 min of severe agitation to four children following physostigmine and nine following placebo (non-significant). An increased rate of postoperative nausea and vomiting (45% vs. 15%, P < 0.05) was the only adverse effect observed.

Severe emergence agitation might be related to a central anticholinergic syndrome as diagnosed empirically with a successful treatment with physostigmine. However, the results of this study do not support its routine use. The substance may augment the therapeutic options if injected slowly and after suitable prophylaxis to avoid postoperative nausea and vomiting.