title: Nitrous oxide scavenging in dental surgery. II. An evaluation of a local exhaust system.
abstract: A deleterious effect on physical and mental health of chronic exposure to trace concentrations of nitrous oxide has been reported. Despite careful handling and sedation technique, gas-tight equipment and breathing circuits, a non-recirculation ventilation system and efficient expired and excess gas scavenging equipment, high local nitrous oxide concentrations may occur e.g. with the use of poorly fitting nose masks and/or the administration of nitrous oxide to uncooperative patients. Local exhaust systems have proved valuable in such situations. The aim of this study was to determine the optimal location of a local exhaust system in relation to leakage in an experimental situation with high local nitrous oxide contamination in a dental surgery and to establish the necessary evacuation capacity of such a local exhaust system. Four different evacuation capacities, 140, 200, 260 and 300m3/h, and three different distances from the patient to the nozzle of the local exhaust system, 10, 20, 30 cm, were tested. With the local exhaust system used in this study, an optimal capacity of about 200 m3/h and a position 20 cm or less in front of the patient seem to meet requirements of occupational exposure to nitrous oxide set by national boards of safety and health.
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000032:analysis; D000395:Air Pollutants, Occupational / Q000032:analysis; D000397:Air Pollution / Q000517:prevention & control*; D000766:Anesthesia, Dental / Q000295:instrumentation*; D004781:Environmental Exposure; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006801:Humans; D009609:Nitrous Oxide / Q000032:analysis
chemical_list: D000393:Air Pollutants; D000395:Air Pollutants, Occupational; D009609:Nitrous Oxide