title: Tubing length for long-term oxygen therapy.
abstract: BACKGROUND
  Most patients on long-term oxygen therapy use stationary oxygen delivery systems. It is not uncommon for guidelines to instruct patients to use tubing lengths no longer than 19.68 ft (6 m) when using an oxygen concentrator and 49.21 ft (15 m) when using cylinders. However, these concepts are not based on sufficient evidence. Thus, our objective was to evaluate whether a 98.42-ft (30-m) tubing length affects oxygen flow and FIO2 delivery from 1 cylinder and 2 oxygen concentrators.
  
  
  METHODS
  The 3 oxygen delivery systems were randomly selected, and 1, 3, and 5 L/min flows and FIO2 were measured 5 times at each flow at the proximal and distal outlets of the tubing by a gas-flow analyzer. Paired Student t test was used to analyze the difference between flows and FIO2 at proximal and distal outlets of tubing length.
  
  
  RESULTS
  A total of 45 flows were measured between proximal and distal outlets of the 98.42-ft (30-m) tubing. Flows were similar for 1 and 3 L/min, but distal flow was higher than proximal flow at 5 L/min (5.57×5.14 L/min, P<.001). FIO2 was lower at distal than proximal outlet tubing at flows 1, 3, and 5 L/min, but the mean difference between measurements was less than 1%.
  
  
  CONCLUSIONS
  Tubing length of 98.42 ft (30 m) may be used by patients for home delivery oxygen with flows up to 5 L/min, as there were no important changes in flows or FIO2.
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Aguiar
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil. josydavidson@yahoo.com.br.
authors.forename: Josy
authors.initials: J
authors.lastname: Davidson
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Andréa K
authors.initials: AK
authors.lastname: Carvalho
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Vinícius C
authors.initials: VC
authors.lastname: Iamonti
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Cortopassi
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Oliver A
authors.initials: OA
authors.lastname: Nascimento
authors.affiliation: Respiratory Division, Departament of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: José R
authors.initials: JR
authors.lastname: Jardim
mesh_terms: D004867:Equipment Design; D017408:Guidelines as Topic; D006801:Humans; D010100:Oxygen / Q000008:administration & dosage*; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D011897:Random Allocation; D015203:Reproducibility of Results; D012648:Self Care / Q000295:instrumentation*; D013997:Time Factors
chemical_list: D010100:Oxygen
keywords: instrumentation; laboratory test; oxygen inhalation therapy