title: Use of helium-oxygen mixture in adult patients presenting with exacerbations of asthma and chronic obstructive pulmonary disease: a systematic review.
abstract: We examined systematically all controlled and cross-over randomised trials in patients with acute exacerbations of asthma and chronic obstructive pulmonary disease comparing Heliox against air-oxygen mixtures. Fourteen studies were identified. In asthma studies, peak expiratory flow rate (PEFR) was increased by an average of 29.6% (95% CI 16.6-42.6) by Heliox-driven nebulisers, or by 13.3 l.min(-1) (95% CI 3.71-22.81) absolute. In studies of patients with chronic obstructive pulmonary disease receiving non-invasive ventilation the arterial carbon dioxide tension (P(a)co(2)) and respiratory rate were unchanged: weighted mean difference for P(a)co(2)-0.29kPa (95% CI - 0.64-0.07) favoured Heliox, and for respiratory rate 1.6 breaths.min(-1) (95% CI - 0.93, 4.14) favoured control. Heliox minimally reduced the work of breathing in intubated patients, and reduced intrinsic positive end expiratory pressure (iPEEP). The use of Heliox to drive nebulisers in patients with acute asthma slightly improves airflow measures. We were unable to determine whether this improved recovery.
authors.affiliation: Intensive Care Medicine and General Medicine, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK. ccolebourn@doctors.org.uk
authors.forename: C L
authors.initials: CL
authors.lastname: Colebourn
authors.forename: V
authors.initials: V
authors.lastname: Barber
authors.forename: J D
authors.initials: JD
authors.lastname: Young
mesh_terms: D000328:Adult; D001249:Asthma / Q000503:physiopathology / Q000628:therapy*; D018592:Cross-Over Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006371:Helium / Q000627:therapeutic use*; D006801:Humans; D009330:Nebulizers and Vaporizers; D010100:Oxygen / Q000627:therapeutic use*; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial / Q000379:methods; D014939:Work of Breathing
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen