Background International asthma guidelines recommend against epinephrine (adrenaline) administration in acute asthma unless associated with anaphylaxis or angio-oedema. However, administration of intramuscular epinephrine in addition to nebulised selective β2-agonist is recommended for acute severe or life-threatening asthma in many prehospital guidelines. We conducted a systematic review to determine the efficacy of epinephrine in comparison to selective β2-agonist in acute asthma. Methods We included peer-reviewed publications of randomised controlled trials (RCTs) that enrolled children or adults in any healthcare setting and compared epinephrine by any route to selective β2-agonist by any route for an acute asthma exacerbation. The primary outcome was treatment failure, including hospitalisation, need for intubation or death. Results Thirty-eight of 1140 studies were included. Overall quality of evidence was low. Seventeen studies contributed data on 1299 participants to the meta-analysis. There was significant statistical heterogeneity, I2=56%. The pooled Peto’s OR for treatment failure with epinephrine versus selective β2-agonist was 0.99 (0.75 to 1.32), p=0.95. There was strong evidence that recruitment age group was associated with different estimates of the odds of treatment failure; with studies recruiting adults-only having lower odds of treatment failure with epinephrine. It was not possible to determine whether epinephrine in addition to selective β2-agonist improved outcomes. Conclusion The low-quality evidence available suggests that epinephrine and selective β2-agonists have similar efficacy in acute asthma. There is a need for high-quality double-blind RCTs to determine whether addition of intramuscular epinephrine to inhaled or nebulised selective β2-agonist improves outcome. PROSPERO registration number CRD42017079472. Data are available upon reasonable request. Data extracted from included studies as part of full-text review are available upon reasonable request to the corresponding author.

中文翻译：

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肾上腺素（肾上腺素）与选择性 β-2 受体激动剂在成人或儿童急性哮喘中的比较：系统评价和荟萃分析

背景 国际哮喘指南建议不要在急性哮喘中使用肾上腺素（肾上腺素），除非与过敏反应或血管性水肿相关。然而，在许多院前指南中，对于急性重症或危及生命的哮喘，除了雾化选择性 β2 激动剂外，还建议使用肌肉注射肾上腺素。我们进行了一项系统评价，以确定肾上腺素与选择性 β2 激动剂在急性哮喘中的疗效对比。方法 我们纳入了随机对照试验 (RCT) 的同行评审出版物，这些试验招募了任何医疗机构的儿童或成人，并比较了任何途径的肾上腺素与任何途径的选择性 β2 受体激动剂对急性哮喘发作的影响。主要结局是治疗失败，包括住院、需要插管或死亡。结果共纳入 1140 项研究中的 38 项。总体证据质量低。17 项研究为荟萃分析提供了 1299 名参与者的数据。存在显着的统计学异质性，I2=56%。肾上腺素与选择性β2-激动剂治疗失败的合并Peto's OR为0.99（0.75至1.32），p = 0.95。有强有力的证据表明，招募年龄组与对治疗失败几率的不同估计相关；研究仅招募成年人，肾上腺素治疗失败的几率较低。无法确定除了选择性 β2 受体激动剂外，肾上腺素是否能改善预后。结论 现有的低质量证据表明，肾上腺素和选择性 β2 受体激动剂在急性哮喘中具有相似的疗效。需要高质量的双盲 RCT 来确定在吸入或雾化选择性 β2 受体激动剂中添加肌内肾上腺素是否能改善预后。PROSPERO 注册号 CRD42017079472。可根据合理要求提供数据。作为全文审查的一部分，从纳入研究中提取的数据可根据通讯作者的合理要求提供。