Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebuliser treatment and chest physiotherapy in clinical practice: implications for management of pandemic influenza and other airborne infections
Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebuliser treatment and chest physiotherapy in clinical practice: implications for management of pandemic influenza and other airborne infections
复制标题
DOI：
10.3310/hta14460-02
复制
发表时间：
2010-10-01
影响因子：
3.6
通讯作者：
Dickinson, R. J.
中科院分区：
文献类型：
--
作者：
Simonds, A. K.;Hanak, A.;Dickinson, R. J.
背景：流感病毒被认为是通过飞沫传播的，但气溶胶传播的作用尚不清楚，以前的研究也没有对其进行评估。氧疗、雾化给药和呼吸机支持是临床上用于治疗流感病毒感染的治疗方法，被认为是产生飞沫或气雾剂的治疗方法。目的：通过测量雾化吸入、雾化吸入、雾化吸入和胸部理疗过程中飞沫的大小、地理分布和在干预措施停止后随时间的消退来评估雾化/气雾剂在输送系统周围的扩散特征。方法：(1)正常对照组、(2)有肺炎症状的受试者和(3)因感染加重而住院的慢性肺病患者。每组都接受氧疗，使用通风式面罩系统的NIV，以及带有非通气式面罩和呼气过滤器的改进电路，以及雾化生理盐水。患者组接受了一段时间的标准化胸部理疗。结果：与基线值相比，使用排气式口罩的患者(p=0.042)和鼻翼受试者(p=0.044)产生了较大直径范围的液滴(p=0.044)，但在正常对照组(p=0.379)中，大液滴的数量没有增加。胸部。理疗产生的液滴主要为10微米(p=0.003)，与患者的NIV液滴计数一样，这些液滴显著减少了1米。氧疗不会增加任何大小范围的液滴数量。结论：雾化生理盐水和胸腔理疗均为雾化(而不是气雾化)产生雾滴的过程，产生的雾滴大小约为10微米。由于它们的质量大，大多数在1米内掉落到局部表面。唯一产生气雾剂的设备是喷雾器，输出轮廓与喷雾器的特征一致，而不是患者散布的大液滴。这些发现表明，提供NIV和胸部物理治疗的医护人员，在感染患者1米范围内工作，应该有更高水平的呼吸保护，但旨在限制气雾剂传播的感染控制措施可能与这些程序相关性较小。这些结果可能对其他通过空气传播的感染，如严重急性呼吸综合征和结核病，以及大流行性流感感染具有感染控制意义。
Background: Influenza viruses are thought to be spread by droplets, but the role of aerosol dissemination is unclear and has not been assessed by previous studies. Oxygen therapy, nebulised medication and ventilatory support are treatments used in clinical practice to treat influenzal infection are thought to generate droplets or aerosols.Objectives: Evaluation of the characteristics of droplet/aerosol dispersion around delivery systems during non-invasive ventilation (NIV), oxygen therapy, nebuliser treatment and chest physiotherapy by measuring droplet size, geographical distribution of droplets, decay in droplets over time after the interventions were discontinued.Methods: Three groups were studied: (1) normal controls, (2) subjects with coryzal symptoms and (3) adult patients with chronic lung disease who were admitted to hospital with an infective exacerbation. Each group received oxygen therapy, NIV using a vented mask system and a modified circuit with non-vented mask and exhalation filter, and nebulised saline. The patient group had a period of standardised chest physiotherapy treatment. Droplet counts in mean diameter size ranges from 0.3 to >10 mu m were measured with an counter placed adjacent to the face and at a 1-m distance from the subject/patient, at the height of the nose/mouth of an average health-care worker.Results: NIV using a vented mask produced droplets in the large size range (>10 mu m) in patients (p = 0.042) and coryzal subjects (p = 0.044) compared with baseline values, but not in normal controls (p = 0.379), but this increase in large droplets was not seen using the NIV circuit modification. Chest. physiotherapy produced droplets predominantly of >10 mu m (p = 0.003), which, as with NIV droplet count in the patients, had fallen significantly by 1 m. Oxygen therapy did not increase droplet count in any size range. Nebulised saline delivered droplets in the small- and medium-size aerosol/droplet range, but did not increase large-size droplet count.Conclusions: NIV and:chest physiotherapy are droplet (not aerosol)-generating procedures, producing droplets of > 10 mu m in size. Due to their large mass, most fall out on to local surfaces within 1 m. The only device producing an aerosol was the nebuliser and the output profile is consistent with nebuliser characteristic rather than dissemination of large droplets from patients. These findings suggest that health-care workers providing NIV and chest physiotherapy, working within 1 m of an infected patient should have a higher level of respiratory protection, but that infection control measures designed to limit aerosol spread may have less relevance for these procedures. These results may have infection control implications for other airborne infections, such as severe acute respiratory syndrome and tuberculosis, as well as for pandemic influenza infection.