title: Nitrogen diffusion into closed anesthesia systems.
abstract: OBJECTIVE
  In order to reduce losses of gases through plastic components and to reduce nitrogen accummulation during closed system anaesthesia we investigated either 10 sets of anaesthetic tubing made of silicon as used in standard clinical practice and 10 sets made of latex, which are not used anymore due to concerns about latex allergies. The results were compared to each one set made of conventional industrial rubber.
  
  
  METHODS
  Anaesthetic tubings were connected to ventilators with low fresh gas losses, suitable for closed system anaesthesia. For nitrogen measurements, a mass spectrometer was used. The fresh gas flow was set to exceed losses by leakages and the amount of gases, extracted from the system by the mass spectrometer.
  
  
  RESULTS
  Highest accumulation of nitrogen was found using tubings made of silicone.
  
  
  CONCLUSIONS
  If closed anaesthetic systems in the future will be used in intensive care therapy or in case of long lasting procedures in which closed system anaesthesia is proceeded, materials other than silicone should be investigated to avoid regular purging of system and consecutive losses of gas mixtures.
authors.affiliation: Department of Cardiac Anesthesia, University of Ulm, Ulm, Germany. thomas.marx@medizin.uni-ulm.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Marx
authors.forename: Helmuth
authors.initials: H
authors.lastname: Reinelt
authors.forename: Kerstin
authors.initials: K
authors.lastname: Plotzki
authors.forename: Uwe
authors.initials: U
authors.lastname: Schirmer
mesh_terms: D000764:Anesthesia, Closed-Circuit / Q000379:methods*; D004058:Diffusion; D004867:Equipment Design; D006801:Humans; D013058:Mass Spectrometry; D008422:Materials Testing; D009584:Nitrogen / Q000032:analysis*; D010969:Plastics; D012408:Rubber; D012825:Silicon; D012122:Ventilators, Mechanical
chemical_list: D010969:Plastics; D012408:Rubber; D009584:Nitrogen; D012825:Silicon