title: Helium/oxygen mixture reduces the work of breathing at the end of the weaning process in patients with severe chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  To test the hypothesis that helium/oxygen mixture can reduce the work of breathing at the end of the weaning process in patients with chronic obstructive pulmonary disease.
  
  
  METHODS
  Prospective, randomized, crossover study.
  
  
  METHODS
  Two medical intensive care units at two university tertiary care centers.
  
  
  METHODS
  Thirteen patients with chronic obstructive pulmonary disease evaluated just before and after extubation.
  
  
  METHODS
  Helium/oxygen and air/oxygen mixtures were administered sequentially, for 20 mins each, in a randomized order, just before extubation. It was possible to repeat the study after extubation in five patients.
  
  
  RESULTS
  Before extubation, the helium/oxygen mixture induced no significant variation in the breathing pattern. By contrast, it reduced the work of breathing from 1.442 +/- 0.718 J/L (mean +/- sd) to 1.133 +/- 0.500 J/L (p <.05). This reduction was explained mainly by a reduction in the resistive component of the work of breathing from 0.662 +/- 0.376 to 0.459 +/- 0.256 J/L (p <.01). We also observed a slight reduction in the intrinsic positive end-expiratory pressure from 2.9 +/- 2.1 cm H(2)O to 2.1 +/- 1.8 cm H(2)O (p <.05). Similar results were also observed after extubation in five patients in whom the repetition of the study was possible.
  
  
  CONCLUSIONS
  In spontaneously breathing intubated patients with chronic obstructive pulmonary disease recovering from an acute exacerbation, helium/oxygen mixture reduces the work of breathing as well as intrinsic positive end-expiratory pressure without modifying the breathing pattern.
authors.affiliation: Services de Réanimation Médicale, Hôpitaux Européen Georges Pompidou, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Diehl
authors.forename: Alain
authors.initials: A
authors.lastname: Mercat
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Guérot
authors.forename: Fethi
authors.initials: F
authors.lastname: Aïssa
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Teboul
authors.forename: Christian
authors.initials: C
authors.lastname: Richard
authors.forename: Jacques
authors.initials: J
authors.lastname: Labrousse
mesh_terms: D000208:Acute Disease; D000368:Aged; D001784:Blood Gas Analysis; D018592:Cross-Over Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006371:Helium / Q000191:economics / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000191:economics / Q000494:pharmacology / Q000627:therapeutic use*; D010102:Oxygen Inhalation Therapy / Q000191:economics / Q000379:methods*; D018467:Positive-Pressure Respiration, Intrinsic / Q000209:etiology / Q000517:prevention & control; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects; D013990:Tidal Volume / Q000187:drug effects; D016896:Treatment Outcome; D015300:Ventilator Weaning / Q000009:adverse effects / Q000379:methods*; D014797:Vital Capacity / Q000187:drug effects; D014939:Work of Breathing
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen