title: Occupational exposure to nitrous oxide during procedural pain control in children: a comparison of different inhalation techniques and scavenging systems.
abstract: BACKGROUND
  Nitrous oxide (N2 O 50% in oxygen) is commonly used for painful procedures in children. Potential negative health effects associated with chronic workplace exposure limit its use. Safe occupational N2 O exposure concentrations are below 25 ppm environmental concentration as a time-weighted average (TWA) and below 200 ppm as a short-time exposure level (STEL) of 15 min.
  
  
  OBJECTIVE
  The aim was to assess occupational exposure of staff during nitrous oxide administration to children using different inhalation delivery devices and scavenging systems.
  
  
  METHODS
  Staff nitrous oxide exposure during use of a double face mask (DFM) with or without a demand valve (DV) was compared with a conventional single face mask (FM). We also compared exposure using the hospital central scavenging system with a portable evacuation system. N2 O concentrations, representing exposure values, were monitored within proximity to staff. Urine N2 O concentration was measured in staff administering the N2 O at the end of the procedural session.
  
  
  RESULTS
  The mean and median values of TWA and STEL within the working area were lower than recommended values in the DFM (10.8, 11.6 ppm for TWA; 13.9, 11.0 ppm for STEL) and DFM-DV groups (2.3, 2.8 ppm for TWA; 4.4, 3.5 ppm for STEL) using the portable evacuation system. The N2 O urine exposure in DFM-DV group was lower than DFM group: a mean difference of 9.56 ppm (95% CI 2.65-16.46). Staff N2 O urinary concentrations were within safe biological limits in both the DFM and DFM-DV groups. High exposure concentrations to N2 O were recorded in all FM and FM-DV environmental and biological samples.
  
  
  CONCLUSIONS
  The DFM system, with or without a DV, connected to a portable evacuation system during N2 O administration to children for painful procedures kept N2 O levels within the local environment below recommended limits.
authors.affiliation: Pain Service, "A. Meyer" Children's Hospital, Florence, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Messeri
authors.affiliation: Pain Service, "A. Meyer" Children's Hospital, Florence, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Amore
authors.affiliation: Occupational Medicine Division, Careggi Hospital, Florence, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Dugheri
authors.affiliation: Occupational Medicine Division, Careggi Hospital, Florence, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bonari
authors.affiliation: Occupational Medicine Division, Careggi Hospital, Florence, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Pompilio
authors.affiliation: Department of Experimental and Clinical Medicine, Health Research Service Unit, University of Florence, Florence, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Arcangeli
authors.affiliation: Department of Neuroscience and Neuroanaesthesia, "A. Meyer" Children's Hospital, Florence, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Rizzo
mesh_terms: D000293:Adolescent; D018685:Anesthetics, Inhalation / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D004867:Equipment Design; D015920:Gas Scavengers; D006801:Humans; D007223:Infant; D008397:Masks; D009609:Nitrous Oxide / Q000652:urine*; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D059408:Pain Management / Q000379:methods*; D010564:Personnel, Hospital / Q000706:statistics & numerical data*; D011446:Prospective Studies
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide
keywords: biological monitoring; children; healthcare environment; nitrous oxide; occupational exposure; scavenger system