Investigation of nitrous oxide pollution arising from inhalational sedation for the extraction of teeth in child patients.

Abstract

(i) TO test whether the exposure of dental staff to nitrous oxide during inhalational sedation with nitrous oxide/oxygen for extractions in children complies with specified occupational exposure standards, and (ii) to assess the atmospheric nitrous oxide concentration at one site close to the breathing zone of the operator/sedationist and to determine which patient- and sedation-related factors affect the level of nitrous oxide pollution. Prospective study. Dental hospital sedation department, Newcastle Dental Hospital, UK. 20 inhalational sedation clinics each of 2 hours duration were evaluated, during which a total of 60 children aged 4-15 years had extractions carried out. Nitrous oxide was administered via a nose mask from a Quantiflex MDM inhalational sedation machine and active scavenging was used throughout. Exposure of dental staff was measured using personal dosimetry. Atmospheric nitrous oxide pollution at one fixed point, close to the breathing zone of the operator/sedationist, was assessed using infra-red gas analyser. Mean exposure of the operator/sedationist to nitrous oxide during a single treatment clinic was 211 ppm, for the close support nurse 77 ppm and for the second nurse 67 ppm. Expressed as an 8 hour time-weighted average, the mean exposures were 39 ppm for the operator/sedationist, 17 ppm for the close support nurse and 15 ppm for the second nurse. The atmospheric nitrous oxide concentration varied during the clinics, with a maximum concentration of 538 ppm an a minimum that exceeded 100 ppm. There was a 71 minute delay following discharge of the last patient before atmospheric levels fell to zero. During sessions the degree of atmospheric pollution was inversely related to patient age (rc = -0.61, P < 0.05). There was a positive correlation between atmospheric pollution at the single point and the maximum percentage of nitrous oxide administered to each patient (rc = 0.57, P < 0.05). In this study, staff exposure to nitrous oxide complied with the national occupational exposure standard but there was still considerable atmospheric nitrous oxide pollution during inhalational sedation for paediatric exodontia.