[Occupational exposure to nitrous oxide and sevoflurane during pediatric anesthesia: evaluation of an anesthetic gas extractor].

OBJECTIVES: To determine the level of occupational exposure to anesthetic gases in the absence of an extractor during pediatric anesthesia and to assess the efficacy of a purpose-built extraction system.

METHODS: The patients were 24 children undergoing tonsillectomy and adenoidectomy. Gases were extracted from the room for 1 group and were not extracted for the other group (n=12 in each group). Induction was with 8% sevoflurane, 60% nitrous oxide (N2O), 40% oxygen at a flow rate of 8 L x min(-1) through a Mapleson C circuit. Maintenance was with 2% sevoflurane at the same flow rate and gas mixture under spontaneous ventilation with an endotracheal tube and a Mapleson D circuit. The circuits were equipped with an airway pressure-limiting valve to allow connection to an anesthetic gas extractor. Ambient levels of sevoflurane and N2O were measured in the breathing area around the anesthesiologist. The surgeon and the nurse were asked about symptoms related to occupational exposure.

RESULTS: The mean (SD) exposure to N2O and sevoflurane in the group without an extractor was 423 (290) and 12 (10.9) parts per million (ppm), respectively. In the group working with the extractor, exposure was 94% and 91% lower: 24.7 (26) and 1.1 (1) ppm (P<.001). A higher incidence of noticing a "smell of gas" was registered for the group without an extractor (87% vs 11% in the extractor group, P=.003). Higher rates were also found for general discomfort (62% vs 11%, P=.05), nausea (62% vs 0%, P=.009), and headache (62% vs 0%, P=.009) in the absence of the extractor.

CONCLUSIONS: Gas extraction decreased the level of exposure by up to 94%, achieving levels that were below the recommended limits and greatly reducing occupational risk.