Major Trauma Centre, Imperial College Healthcare NHS Trust, London, UK
Major Trauma Centre, Imperial College Healthcare NHS Trust, London, UK.
BMJ Open. 2020 Oct 16;10(10):e040321. doi: 10.1136/bmjopen-2020-040321.
In patient-facing healthcare workers delivering secondary care, what is the evidence behind UK Government personal protective equipment (PPE) guidance on surgical masks versus respirators for SARS-CoV-2 protection?
Two independent reviewers performed a rapid review. Appraisal was performed using Critical Appraisal Skills Programme checklists and Grading of Recommendations, Assessment, Development and Evaluations methodology. Results were synthesised by comparison of findings and appraisals.
MEDLINE, Google Scholar, UK Government COVID-19 website and grey literature.
Studies published on any date containing primary data comparing surgical facemasks and respirators specific to SARS-CoV-2, and studies underpinning UK Government PPE guidance, were included.
Of 30 identified, only 3 laboratory studies of 14 different respirators and 12 surgical facemasks were found. In all three, respirators were significantly more effective than facemasks when comparing protection factors, reduction factors, filter penetrations, total inspiratory leakages at differing particle sizes, mean inspiratory flows and breathing rates. Tests included live viruses and inert particles on dummies and humans. In the six clinical studies (6502 participants) included the only statistically significant result found continuous use of respirators more effective in clinical respiratory illness compared with targeted use or surgical facemasks. There was no consistent definition of 'exposure' to determine the efficacy of respiratory protective equipment (RPE). It is difficult to define 'safe'.
There is a paucity of evidence on the comparison of facemasks and respirators specific to SARS-CoV-2, and poor-quality evidence in other contexts. The use of surrogates results in extrapolation of non-SARS-CoV-2 specific data to guide UK Government PPE guidance. The appropriateness of this is unknown given the uncertainty over the transmission of SARS-CoV-2.This means that the evidence base for UK Government PPE guidelines is not based on SARS-CoV-2 and requires generalisation from low-quality evidence of other pathogens/particles. There is a paucity of high-quality evidence regarding the efficacy of RPE specific to SARS-CoV-2. UK Government PPE guidelines are underpinned by the assumption of droplet transmission of SARS-CoV-2.These factors suggest that the triaging of filtering face piece class 3 respirators might increase the risk of COVID-19 faced by some.
在提供二级保健的面向患者的医疗保健工作者中，英国政府关于外科口罩与呼吸器用于保护 SARS-CoV-2 的个人防护设备 (PPE) 指南背后有哪些证据？
两名独立评审员进行了快速审查。使用关键评估技能计划清单和推荐评估、制定和评估方法进行评估。通过比较发现和评估结果来综合结果。
MEDLINE、Google Scholar、英国政府 COVID-19 网站和灰色文献。
包含比较针对 SARS-CoV-2 的外科口罩和呼吸器的原始数据的研究，以及为英国政府 PPE 指南提供依据的研究，无论其发表日期如何，均被纳入研究范围。
在确定的 30 项研究中，仅发现了 3 项针对 14 种不同呼吸器和 12 种外科口罩的实验室研究。在所有三种情况下，与口罩相比，呼吸器在保护因子、降低因子、过滤渗透率、不同粒径下的总吸气泄漏、平均吸气流量和呼吸速率方面均具有更高的效率。测试包括在模拟人和人体上使用活病毒和惰性颗粒。在纳入的 6 项临床研究（6502 名参与者）中，唯一发现的具有统计学意义的结果是，与有针对性使用或外科口罩相比，连续使用呼吸器在临床呼吸道疾病中更有效。没有一致的“暴露”定义来确定呼吸防护设备 (RPE) 的功效。“安全”很难定义。
针对 SARS-CoV-2 的口罩和呼吸器的比较证据很少，而其他情况下的证据质量也很差。使用替代物会导致将非 SARS-CoV-2 特异性数据外推以指导英国政府 PPE 指南。鉴于 SARS-CoV-2 传播的不确定性，这种方法的适当性尚不清楚。这意味着英国政府 PPE 指南的证据基础并非基于 SARS-CoV-2，而是需要从其他病原体/颗粒的低质量证据中进行推断。针对 SARS-CoV-2 的 RPE 功效的高质量证据很少。英国政府 PPE 指南的依据是假设 SARS-CoV-2 通过飞沫传播。这些因素表明，对 3 级过滤式口罩的分类可能会增加一些人面临 COVID-19 的风险。
