Ho Anthony M-H, Lee Anna, Karmakar Manoj K, Dion Peter W, Chung David C, Contardi LeeAnne H
Department of Anaesthesia and Intensive Care, Faculty of Medicine, The Chinese University of Hong Kong, SAR.
Chest. 2003 Mar;123(3):882-90. doi: 10.1378/chest.123.3.882.
To evaluate, by systematic review, the efficacy of heliox on respiratory mechanics and outcomes in patients with acute asthma.
The search strategy included searching electronic databases (MEDLINE, EMBASE, and The Cochrane Library) and the references of relevant articles. Study quality was assessed based on allocation concealment. Randomized controlled trials (RCTs) comparing heliox to an air-oxygen mixture (airO(2)) as an adjunct treatment in patients with acute asthmatic attacks were analyzed. For the qualitative portion of the analysis, all reports of the use of heliox in patients with acute asthma were included.
Four RCTs (n = 278) were found to have a common respiratory parameter (peak expiratory flow rate as a percentage of predicted) suitable for meta-analysis. Within the 92% confidence interval (CI), there was a small benefit with the use of heliox compared to airO(2) (weighted mean difference, + 3%; 95% CI, - 2 to + 8%). There was also a slight improvement in the dyspnea index (weighted mean difference, 0.60; 95% CI, 0.04 to 1.16) with the use of heliox over airO(2). Overall, five RCTs, one nonrandomized unblinded parallel trial, one retrospective case-matched control trial, three case series, and one case report had results in favor of heliox; one RCT and one case series showed no improvement with heliox; one RCT showed a possible detrimental effect with heliox; and 1 small RCT was inconclusive. Most investigators did not prevent entrainment of room air during heliox use or compensate for the lower nebulizing efficiency of heliox.
Based on surrogate markers, heliox may offer mild-to-moderate benefits in patients with acute asthma within the first hour of use, but its advantages become less apparent beyond 1 h, as most conventionally treated patients improve to similar levels, with or without it. The effect of heliox may be more pronounced in more severe cases. There are insufficient data on whether heliox can avert tracheal intubation, or change intensive care and hospital admission rates and duration, or mortality.
通过系统评价，评估氦氧混合气对急性哮喘患者呼吸力学及预后的疗效。
检索策略包括检索电子数据库（MEDLINE、EMBASE和Cochrane图书馆）以及相关文章的参考文献。基于分配隐藏评估研究质量。分析比较氦氧混合气与空气 - 氧气混合气体（airO₂）作为急性哮喘发作患者辅助治疗的随机对照试验（RCT）。对于分析的定性部分，纳入所有关于氦氧混合气用于急性哮喘患者的报告。
发现四项RCT（n = 278）具有适合进行荟萃分析的共同呼吸参数（呼气峰值流速占预测值的百分比）。在92%置信区间（CI）内，与airO₂相比，使用氦氧混合气有轻微益处（加权平均差，+ 3%；95% CI，- 2至 + 8%）。使用氦氧混合气相比于airO₂，呼吸困难指数也有轻微改善（加权平均差，0.60；95% CI，0.04至1.16）。总体而言，五项RCT、一项非随机非盲平行试验、一项回顾性病例匹配对照试验、三个病例系列和一份病例报告的结果支持氦氧混合气；一项RCT和一个病例系列显示使用氦氧混合气无改善；一项RCT显示使用氦氧混合气可能有有害作用；一项小型RCT结果不明确。大多数研究者在使用氦氧混合气期间未防止室内空气混入，也未补偿氦氧混合气较低的雾化效率。
基于替代指标，氦氧混合气在使用的第一小时内可能对急性哮喘患者有轻度至中度益处，但超过1小时后其优势变得不那么明显，因为大多数常规治疗的患者无论有无使用氦氧混合气都改善到相似水平。氦氧混合气的效果在更严重的病例中可能更显著。关于氦氧混合气能否避免气管插管、改变重症监护和住院率及住院时间或死亡率的数据不足。
