Heliox for nonintubated acute asthma patients
2003; Cochrane; Linguagem: Inglês
10.1002/14651858.cd002884
ISSN1469-493X
AutoresGustavo J. Rodrigo, Charles V. Pollack, Carlos Rodrigo, BH Rowe,
Tópico(s)Asthma and respiratory diseases
ResumoBackground Helium and oxygen mixtures (heliox), have been used sporadically in respiratory medicine for decades. Their use in acute respiratory emergencies such as asthma has been the subject of considerable debate. Despite the lapse of more than 60 years since it was first proposed, the role of heliox in treating patients with acute severe asthma remains unclear. Objectives To determine the effect of the addition of heliox to standard medical care on the course of acute asthma, as measured by pulmonary function testing and clinical endpoints. Search methods Randomised controlled trials were identified from the Cochrane Airways Review Group Asthma Register which is a compilation of systematic searches of CINAHL, EMBASE, MEDLINE, and CENTRAL and hand searching of the 20 most productive respiratory care journals. In addition, primary authors and experts were contacted to identify eligible studies. References from included studies, known reviews and texts were also searched. Selection criteria Studies were selected for inclusion in the review if they met the following inclusion criteria: 1) randomised, single or double blind, controlled trials; 2) children or adults with a clinical diagnosis of acute asthma seen in emergency departments or equivalent acute care settings; and 3) compared treatment with inhaled heliox to placebo (oxygen or air). Two reviewers independently assessed the studies for inclusion and quality assessment; disagreement was resolved by a third reviewer and consensus. Data collection and analysis Data from all included trials were combined using the Review Manager (Version 4.1) using random effects weighted mean (WMD) and standardised mean differences (SMD), with 95% confidence intervals (95% CI). Homogeneity of effect sizes were tested with the Dersimonian and Laird method with p 2 vs. 3). The main outcome variable was spirometric measurements (PEF % predicted, PEF L/min, FEV1 % of predicted, FEV1L). Heliox use did not improve pulmonary functions compared to standard care (SMD = 0.13; 95% CI: ‐0.09 to 0.34). All pulmonary function tests were recorded during heliox administration (15 to 60 min). The test of homogeneity was not significant (p=0.25). There were no significant differences between groups when adults vs. children, high vs. low quality, and high vs. low heliox dose studies were compared. Authors' conclusions The existing evidence does not provide support for the administration of helium‐oxygen mixtures to ED patients with moderate to severe acute asthma. At this time, heliox treatment does not have a role to play in the initial treatment of patients with acute asthma. Since these conclusions are based upon between‐group comparisons and small studies, they should be interpreted with caution. Additional research in this setting is needed.
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