[Workplace contamination from sevoflurane. Concentration measurement during bronchosopy in children]

General anaesthetic agents are frequently used for paediatric bronchoscopy. A disadvantage of open-system anaesthesia is the contamination of the working environment. The aim of this study was to determine the exposure of the anaesthesiologist and endoscopist during paediatric bronchoscopy under general anaesthesia in different working environments and to compare these measurements to the currently valid international threshold limits.

Twenty-five children (ASA I-III) scheduled for diagnostic bronchoscopy were included in the study. After inhalational induction, all patients were intubated with a nonflexible bronchoscope and manually ventilated through a side-arm of the bronchoscope. Maintenance of anaesthesia was achieved with sevoflurane (2-3 vol.%) in pure oxygen. Trace concentrations were measured every 90 s in the breathing zones of the operating theatre (OT) personnel by means of a highly sensitive direct-reading instrument (Brüel & Kjaer 1302). The lower detection limit was 0.02 ppm. The investigation was done in an OT with and without air-conditioning and a scavenging system.

The mean age of the children was 50.3 months (range: 3-109 months). Ventilation and oxygenation were stable throughout the bronchoscopic procedure. Mean exposure to sevoflurane in the OT without air-conditioning and a scavenging system was over 40 ppm for the anaesthetist and 50 ppm for the endoscopist. All international threshold limit values were exceeded. Peak concentrations higher than 100 ppm could be detected during 40% of the anaesthetics.

The main finding of the present study is that under inhalation anaesthesia with sevoflurane for paediatric bronchoscopy, occupational exposure is higher than all known health regulation guidelines permit. Therefore, the use of total intravenous anaesthesia is advocated even in very small infants.