title: [Risk of accumulation of CO₂ in the oxygen chamber in "HOOD" (Experimental study on test bed)].
abstract: OBJECTIVE
  Oxygen hood is largely used to deliver O₂ to newborn infants with respiratory failure in the northern region of France. The oxygen flow is set to obtain the target arterial blood oxygen saturation. Thus, O₂ flow delivers into the hood may be below the recommended gas flow of 6L/min. However, gas flow below 6L/min exposes to CO₂ rebreathing. The aim of this study was to evaluate the effect of various rates of gas flows on the values of partial pressure of CO₂ into the hood.
  
  
  METHODS
  We measured CO₂ and O₂ partial pressure into hoods of two different volumes (4 and 10L) under two experimental bench test conditions. Protocol 1: gas flow was constant at 6L/min, while oxygen fraction varied from 0.21 to 1. Partial pressure of CO₂ and O₂ were recorded. Protocol 2: while O₂ fraction was kept constant, oxygen flow varied from 0.5 to 7L/min (by step of 0.5L/min). Partial pressure of CO₂ and O₂ were recorded.
  
  
  RESULTS
  Partial pressure of CO₂ increases proportionally to the decrease in the gas flow delivered into the hood, and reached 14 mmHg at gas flow of 0.5L/min.
  
  
  CONCLUSIONS
  Risk of CO₂ rebreathing exists as soon as the gas is delivered into the hood at minimal flow rates below 6L/min.
authors.affiliation: Service de Néonatologie, CH de Dunkerque, 130, avenue Louis-Herbeaux, 59385 Dunkerque cedex 1, France.
authors.forename: A
authors.initials: A
authors.lastname: Caron Salloum
authors.forename: T
authors.initials: T
authors.lastname: Rakza
authors.forename: J-F
authors.initials: JF
authors.lastname: Diependaele
authors.forename: M-H
authors.initials: MH
authors.lastname: Depoortere
authors.forename: F
authors.initials: F
authors.lastname: Delepoulle
authors.forename: L
authors.initials: L
authors.lastname: Storme
mesh_terms: D000465:Algorithms; D002245:Carbon Dioxide / Q000009:adverse effects* / Q000032:analysis; D005602:France; D006801:Humans; D007231:Infant, Newborn; D008348:Manikins; D010100:Oxygen / Q000008:administration & dosage / Q000032:analysis; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects* / Q000295:instrumentation*; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000628:therapy
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen