[Narcotrend EEG monitoring during total intravenous anaesthesia in 4.630 patients].

INTRODUCTION

The Narcotrend is a new EEG monitor designed to measure the hypnotic component of anaesthesia; however, a major clinical evaluation is still missing. This prospective multicentre study was designed to investigate the feasibility of Narcotrend monitoring in a large number of patients under different clinical conditions and to define its impact on recovery times after propofol-based total intravenous anaesthesia.

METHODS

After legal authority approval and patients'informed consent had been obtained, total intravenous anaesthesia was induced and maintained with propofol and an opioid analgesic at the discretion of the attending anaesthesiologist. In the first 10-15 patients of each centre the anaesthesiologist was blinded to the Narcotrend recordings and propofol was dosed according to clinical needs. In the following patients propofol was infused at a rate sufficient to achieve a target Narcotrend stage of D or E. With termination of propofol infusion,recovery times were recorded and analysed for the patients with or without Narcotrend monitoring; in addition, recovery times were analysed depending on the Narcotrend stage at the moment of termination of propofol infusion.

RESULTS

In total, 4,630 adult patients were studied at 46 institutions, 521 without and 4,109 with Narcotrend monitoring. Demographic data and duration of anaesthesia were comparable. Emergence from anaesthesia was significantly shorter in Narcotrend monitored patients, e.g.opening eyes after 9.8+/-5.9 (mean+/-SD) vs.11.8+/-7.1 min. In addition,awakening was significantly more rapid when the propofol infusion was stopped at a lower level of hypnosis as indicated by Narcotrend monitoring, e.g.opening eyes after 7.1+/-4.5 min with stage C instead of 17.0+/-7.4 min with stage F.

CONCLUSIONS

The EEG monitor Narcotrend can be used for adult patients of different ages and during various surgical procedures.Narcotrend monitoring facilitates a reduction of recovery times after propofol-based total intravenous anaesthesia,presumably by allowing for an individual titration of the propofol dosage. Moreover, it appears that the profile of recovery can be optimised when at the end of surgery,the propofol infusion is controlled to Narcotrend stage C instead of D, E, or F.