title: Effect of heliox- and air-driven nebulized bronchodilator therapy on lung function in patients with asthma.
abstract: BACKGROUND
  This study compares the effect of heliox-driven to that of air-driven bronchodilator therapy on the pulmonary function test (PFT) in patients with different levels of asthma severity.
  
  
  METHODS
  One-hundred thirty-two participants were included in the study. Participants underwent spirometry twice with bronchodilator testing on two consecutive days. Air-driven nebulization was used one day and heliox-driven nebulization the other day in random order crossover design. After a baseline PFT, each participant received 2.5 mg of albuterol sulfate nebulized with the randomized driving gas. Post bronchodilator PFT was repeated after 30 min. The next day, the exact same protocol was repeated, except that the other driving gas was used to nebulize the drug. Participants were subgrouped and analyzed according to their baseline FEV(1) on day 1: Group I, FEV(1) ≥80 %; Group II, 80 % > FEV(1) > 50 %; Group III, FEV(1) ≤50 %. The proportion of participants with greater than 12 % and 200-mL increases from their baseline FEV(1) and the changes from baseline in PFT variables were compared between heliox-driven versus air-driven bronchodilation therapy.
  
  
  RESULTS
  The proportion of participants with >12 % and 200-mL increases from their baseline FEV(1) with air- or heliox-driven bronchodilation was not different with respect to the proportion of participants with baseline FEV(1) ≥80 % (20 vs. 18 %, respectively) and 80 % > FEV(1) > 50 % (36 vs. 43 %, respectively), but it was significantly greater with heliox-driven bronchodilation in participants with FEV(1) ≤50 % (43 vs. 73 %, respectively; p = 0.01). Changes from baseline FVC, FEV(1), FEV(1)/FVC, FEF(25-75) %, FEF(max), FEF(25) %, FEF(50) %, and FEF(75) % were significantly larger with heliox-driven versus air-driven bronchodilation in participants with baseline FEV(1) ≤50 %.
  
  
  CONCLUSIONS
  Improvements in PFT variables are more frequent and profound with heliox-driven compared to air-driven bronchodilator therapy only in asthmatic patients with baseline FEV(1) ≤50 %.
authors.affiliation: Department of Anesthesiology, American University of Beirut, Beirut, Lebanon.
authors.forename: Mohamad F
authors.initials: MF
authors.lastname: El-Khatib
authors.forename: Ghassan
authors.initials: G
authors.lastname: Jamaleddine
authors.forename: Nadim
authors.initials: N
authors.lastname: Kanj
authors.forename: Salah
authors.initials: S
authors.lastname: Zeineddine
authors.forename: Hassan
authors.initials: H
authors.lastname: Chami
authors.forename: Imad
authors.initials: I
authors.lastname: Bou-Akl
authors.forename: Ahmad
authors.initials: A
authors.lastname: Husari
authors.forename: Marwan
authors.initials: M
authors.lastname: Alawieh
authors.forename: Pierre
authors.initials: P
authors.lastname: Bou-Khalil
mesh_terms: D000280:Administration, Inhalation; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage*; D000328:Adult; D000335:Aerosol Propellants; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D058868:Compressed Air; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D005541:Forced Expiratory Volume; D006371:Helium; D006801:Humans; D007861:Lebanon; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008450:Maximal Midexpiratory Flow Rate; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010100:Oxygen; D012720:Severity of Illness Index; D013147:Spirometry; D016896:Treatment Outcome; D014797:Vital Capacity
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D000335:Aerosol Propellants; D001993:Bronchodilator Agents; D006371:Helium; C038949:heliox; D000420:Albuterol; D010100:Oxygen