Aerosol delivery in respiratory syncytial virus bronchiolitis: hood or face mask?

Nebulised hypertonic saline solution for acute bronchiolitis in infants

BACKGROUND

Airway oedema (swelling) and mucus plugging are the principal pathological features in infants with acute viral bronchiolitis. Nebulised hypertonic saline solution (≥ 3%) may reduce these pathological changes and decrease airway obstruction. This is an update of a review first published in 2008, and updated in 2010, 2013, and 2017.

OBJECTIVES

To assess the effects of nebulised hypertonic (≥ 3%) saline solution in infants with acute bronchiolitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily, Embase, CINAHL, LILACS, and Web of Science on 13 January 2022. We also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov on 13 January 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs using nebulised hypertonic saline alone or in conjunction with bronchodilators as an active intervention and nebulised 0.9% saline or standard treatment as a comparator in children under 24 months with acute bronchiolitis. The primary outcome for inpatient trials was length of hospital stay, and the primary outcome for outpatients or emergency department (ED) trials was rate of hospitalisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and assessment of risk of bias in included studies. We conducted random-effects model meta-analyses using Review Manager 5. We used mean difference (MD), risk ratio (RR), and their 95% confidence intervals (CI) as effect size metrics.

MAIN RESULTS

We included six new trials (N = 1010) in this update, bringing the total number of included trials to 34, involving 5205 infants with acute bronchiolitis, of whom 2727 infants received hypertonic saline. Eleven trials await classification due to insufficient data for eligibility assessment. All included trials were randomised, parallel-group, controlled trials, of which 30 were double-blinded. Twelve trials were conducted in Asia, five in North America, one in South America, seven in Europe, and nine in Mediterranean and Middle East regions. The concentration of hypertonic saline was defined as 3% in all but six trials, in which 5% to 7% saline was used. Nine trials had no funding, and five trials were funded by sources from government or academic agencies. The remaining 20 trials did not provide funding sources. Hospitalised infants treated with nebulised hypertonic saline may have a shorter mean length of hospital stay compared to those treated with nebulised normal (0.9%) saline or standard care (mean difference (MD) -0.40 days, 95% confidence interval (CI) -0.69 to -0.11; 21 trials, 2479 infants; low-certainty evidence). Infants who received hypertonic saline may also have lower postinhalation clinical scores than infants who received normal saline in the first three days of treatment (day 1: MD -0.64, 95% CI -1.08 to -0.21; 10 trials (1 outpatient, 1 ED, 8 inpatient trials), 893 infants; day 2: MD -1.07, 95% CI -1.60 to -0.53; 10 trials (1 outpatient, 1 ED, 8 inpatient trials), 907 infants; day 3: MD -0.89, 95% CI -1.44 to -0.34; 10 trials (1 outpatient, 9 inpatient trials), 785 infants; low-certainty evidence). Nebulised hypertonic saline may reduce the risk of hospitalisation by 13% compared with nebulised normal saline amongst infants who were outpatients and those treated in the ED (risk ratio (RR) 0.87, 95% CI 0.78 to 0.97; 8 trials, 1760 infants; low-certainty evidence). However, hypertonic saline may not reduce the risk of readmission to hospital up to 28 days after discharge (RR 0.83, 95% CI 0.55 to 1.25; 6 trials, 1084 infants; low-certainty evidence). We are uncertain whether infants who received hypertonic saline have a lower number of days to resolution of wheezing compared to those who received normal saline (MD -1.16 days, 95% CI -1.43 to -0.89; 2 trials, 205 infants; very low-certainty evidence), cough (MD -0.87 days, 95% CI -1.31 to -0.44; 3 trials, 363 infants; very low-certainty evidence), and pulmonary moist crackles (MD -1.30 days, 95% CI -2.28 to -0.32; 2 trials, 205 infants; very low-certainty evidence). Twenty-seven trials presented safety data: 14 trials (1624 infants; 767 treated with hypertonic saline, of which 735 (96%) co-administered with bronchodilators) did not report any adverse events, and 13 trials (2792 infants; 1479 treated with hypertonic saline, of which 416 (28%) co-administered with bronchodilators and 1063 (72%) hypertonic saline alone) reported at least one adverse event such as worsening cough, agitation, bronchospasm, bradycardia, desaturation, vomiting and diarrhoea, most of which were mild and resolved spontaneously (low-certainty evidence).

AUTHORS' CONCLUSIONS

Nebulised hypertonic saline may modestly reduce length of stay amongst infants hospitalised with acute bronchiolitis and may slightly improve clinical severity score. Treatment with nebulised hypertonic saline may also reduce the risk of hospitalisation amongst outpatients and ED patients. Nebulised hypertonic saline seems to be a safe treatment in infants with bronchiolitis with only minor and spontaneously resolved adverse events, especially when administered in conjunction with a bronchodilator. The certainty of the evidence was low to very low for all outcomes, mainly due to inconsistency and risk of bias.

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections (ARIs) pose a global threat. Examples are influenza (H1N1) caused by the H1N1pdm09 virus in 2009, severe acute respiratory syndrome (SARS) in 2003, and coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in 2019. Antiviral drugs and vaccines may be insufficient to prevent their spread. This is an update of a Cochrane Review last published in 2020. We include results from studies from the current COVID-19 pandemic.

OBJECTIVES

To assess the effectiveness of physical interventions to interrupt or reduce the spread of acute respiratory viruses.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, CINAHL, and two trials registers in October 2022, with backwards and forwards citation analysis on the new studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and cluster-RCTs investigating physical interventions (screening at entry ports, isolation, quarantine, physical distancing, personal protection, hand hygiene, face masks, glasses, and gargling) to prevent respiratory virus transmission.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 11 new RCTs and cluster-RCTs (610,872 participants) in this update, bringing the total number of RCTs to 78. Six of the new trials were conducted during the COVID-19 pandemic; two from Mexico, and one each from Denmark, Bangladesh, England, and Norway. We identified four ongoing studies, of which one is completed, but unreported, evaluating masks concurrent with the COVID-19 pandemic. Many studies were conducted during non-epidemic influenza periods. Several were conducted during the 2009 H1N1 influenza pandemic, and others in epidemic influenza seasons up to 2016. Therefore, many studies were conducted in the context of lower respiratory viral circulation and transmission compared to COVID-19. The included studies were conducted in heterogeneous settings, ranging from suburban schools to hospital wards in high-income countries; crowded inner city settings in low-income countries; and an immigrant neighbourhood in a high-income country. Adherence with interventions was low in many studies. The risk of bias for the RCTs and cluster-RCTs was mostly high or unclear. Medical/surgical masks compared to no masks We included 12 trials (10 cluster-RCTs) comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illness (two trials with healthcare workers and 10 in the community). Wearing masks in the community probably makes little or no difference to the outcome of influenza-like illness (ILI)/COVID-19 like illness compared to not wearing masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09; 9 trials, 276,917 participants; moderate-certainty evidence. Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks (RR 1.01, 95% CI 0.72 to 1.42; 6 trials, 13,919 participants; moderate-certainty evidence). Harms were rarely measured and poorly reported (very low-certainty evidence). N95/P2 respirators compared to medical/surgical masks We pooled trials comparing N95/P2 respirators with medical/surgical masks (four in healthcare settings and one in a household setting). We are very uncertain on the effects of N95/P2 respirators compared with medical/surgical masks on the outcome of clinical respiratory illness (RR 0.70, 95% CI 0.45 to 1.10; 3 trials, 7779 participants; very low-certainty evidence). N95/P2 respirators compared with medical/surgical masks may be effective for ILI (RR 0.82, 95% CI 0.66 to 1.03; 5 trials, 8407 participants; low-certainty evidence). Evidence is limited by imprecision and heterogeneity for these subjective outcomes. The use of a N95/P2 respirators compared to medical/surgical masks probably makes little or no difference for the objective and more precise outcome of laboratory-confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; 5 trials, 8407 participants; moderate-certainty evidence). Restricting pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reported, but discomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies (very low-certainty evidence).  One previously reported ongoing RCT has now been published and observed that medical/surgical masks were non-inferior to N95 respirators in a large study of 1009 healthcare workers in four countries providing direct care to COVID-19 patients.  Hand hygiene compared to control Nineteen trials compared hand hygiene interventions with controls with sufficient data to include in meta-analyses. Settings included schools, childcare centres and homes. Comparing hand hygiene interventions with controls (i.e. no intervention), there was a 14% relative reduction in the number of people with ARIs in the hand hygiene group (RR 0.86, 95% CI 0.81 to 0.90; 9 trials, 52,105 participants; moderate-certainty evidence), suggesting a probable benefit. In absolute terms this benefit would result in a reduction from 380 events per 1000 people to 327 per 1000 people (95% CI 308 to 342). When considering the more strictly defined outcomes of ILI and laboratory-confirmed influenza, the estimates of effect for ILI (RR 0.94, 95% CI 0.81 to 1.09; 11 trials, 34,503 participants; low-certainty evidence), and laboratory-confirmed influenza (RR 0.91, 95% CI 0.63 to 1.30; 8 trials, 8332 participants; low-certainty evidence), suggest the intervention made little or no difference. We pooled 19 trials (71, 210 participants) for the composite outcome of ARI or ILI or influenza, with each study only contributing once and the most comprehensive outcome reported. Pooled data showed that hand hygiene may be beneficial with an 11% relative reduction of respiratory illness (RR 0.89, 95% CI 0.83 to 0.94; low-certainty evidence), but with high heterogeneity. In absolute terms this benefit would result in a reduction from 200 events per 1000 people to 178 per 1000 people (95% CI 166 to 188). Few trials measured and reported harms (very low-certainty evidence). We found no RCTs on gowns and gloves, face shields, or screening at entry ports.

AUTHORS' CONCLUSIONS

The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions. There were additional RCTs during the pandemic related to physical interventions but a relative paucity given the importance of the question of masking and its relative effectiveness and the concomitant measures of mask adherence which would be highly relevant to the measurement of effectiveness, especially in the elderly and in young children. There is uncertainty about the effects of face masks. The low to moderate certainty of evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect. The pooled results of RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks. There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection. Hand hygiene is likely to modestly reduce the burden of respiratory illness, and although this effect was also present when ILI and laboratory-confirmed influenza were analysed separately, it was not found to be a significant difference for the latter two outcomes. Harms associated with physical interventions were under-investigated. There is a need for large, well-designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, as well as the impact of adherence on effectiveness, especially in those most at risk of ARIs.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Reconciling Oxygen and Aerosol Delivery with a Hood on In Vitro Infant and Paediatric Models

This study aimed to evaluate optimal aerosol and oxygen delivery with a hood on an infant model and a paediatric model. A facemask and a hood with three inlets, with or without a front cover, were used. A small-volume nebuliser with a unit-dose of salbutamol was used for drug delivery and an air entrainment nebuliser was used to deliver oxygen at 35%. Infant and paediatric breathing patterns were mimicked; a bacterial filter was connected to the end of a manikin trachea for aerosol drug collection, and an oxygen analyser was used to measure the oxygen concentration. For the infant model, inhaled drug dose was significantly higher when the nebuliser was placed in the back of the hood and with a front cover. This was verified by complementary computational simulations in a comparable infant-hood model. For the paediatric model, the inhaled dose was greater with a facemask than with a hood. Oxygen delivery with a facemask and a hood with a front cover achieved a set concentration in both models, yet a hood without a front cover delivered oxygen at far lower concentrations than the set concentration.

A path to successful patient outcomes through aerosol drug delivery to children: a narrative review

Although using aerosolized medications is a mainstay of treatment in children with asthma and other respiratory diseases, there are many issues in terms of device and interface selection, delivery technique and dosing, as well as patient and parental education that have not changed for half a century. Also, due to many aerosol devices and interfaces available on the market and the broad range of patient characteristics and requirements, providing effective aerosol therapy to children becomes a challenge. While aerosol delivery devices are equally effective, if they are age-appropriate and used correctly, the majority of aerosol devices require multiple steps to be used efficiently. Unfortunately, many children with pulmonary diseases have problems with the correct delivery technique and do not gain therapeutic benefits from therapy that result in poor disease management and increased healthcare costs. Therefore, the purpose of this paper is to review the current knowledge on aerosol delivery devices used in children and guide clinicians on the optimum device- and interface-selection, delivery technique, and dosing in this patient population. Strategies on how to deliver aerosolized medications in crying and distressed children and how to educate parents on aerosol therapy and promote patient adherence to prescribed medications are also provided. Future directions of aerosol therapy in children should focus on these issues and implement policies and clinical practices that highlight the potential solutions to these problems.

A technical review of face mask wearing in preventing respiratory COVID-19 transmission

Since the outbreak of the COVID-19 pandemic, most countries have recommended their citizens to adopt social distance, hand hygiene, and face mask wearing. However, wearing face masks has not been well adopted by many citizens. While the reasons are complex, there is a general perception that the evidence to support face mask wearing is lacking, especially for the general public in a community setting. Face mask wearing can block or filter airborne virus-carrying particles through the working of colloid and interface science. This paper assesses current knowledge behind the design and functioning of face masks by reviewing the selection of materials, mask specifications, relevant laboratory tests, and respiratory virus transmission trials, with an overview of future development of reusable masks for the general public. This review highlights the effectiveness of face mask wearing in the prevention of COVID-19 infection.

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections (ARIs) pose a global threat. Examples are influenza (H1N1) caused by the H1N1pdm09 virus in 2009, severe acute respiratory syndrome (SARS) in 2003, and coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in 2019. Antiviral drugs and vaccines may be insufficient to prevent their spread. This is an update of a Cochrane Review published in 2007, 2009, 2010, and 2011. The evidence summarised in this review does not include results from studies from the current COVID-19 pandemic.

OBJECTIVES

To assess the effectiveness of physical interventions to interrupt or reduce the spread of acute respiratory viruses.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, CINAHL on 1 April 2020. We searched ClinicalTrials.gov, and the WHO ICTRP on 16 March 2020. We conducted a backwards and forwards citation analysis on the newly included studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and cluster-RCTs of trials investigating physical interventions (screening at entry ports, isolation, quarantine, physical distancing, personal protection, hand hygiene, face masks, and gargling) to prevent respiratory virus transmission. In previous versions of this review we also included observational studies. However, for this update, there were sufficient RCTs to address our study aims.   DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence. Three pairs of review authors independently extracted data using a standard template applied in previous versions of this review, but which was revised to reflect our focus on RCTs and cluster-RCTs for this update. We did not contact trialists for missing data due to the urgency in completing the review. We extracted data on adverse events (harms) associated with the interventions.

MAIN RESULTS

We included 44 new RCTs and cluster-RCTs in this update, bringing the total number of randomised trials to 67. There were no included studies conducted during the COVID-19 pandemic. Six ongoing studies were identified, of which three evaluating masks are being conducted concurrent with the COVID pandemic, and one is completed. Many studies were conducted during non-epidemic influenza periods, but several studies were conducted during the global H1N1 influenza pandemic in 2009, and others in epidemic influenza seasons up to 2016. Thus, studies were conducted in the context of lower respiratory viral circulation and transmission compared to COVID-19. The included studies were conducted in heterogeneous settings, ranging from suburban schools to hospital wards in high-income countries; crowded inner city settings in low-income countries; and an immigrant neighbourhood in a high-income country. Compliance with interventions was low in many studies. The risk of bias for the RCTs and cluster-RCTs was mostly high or unclear. Medical/surgical masks compared to no masks We included nine trials (of which eight were cluster-RCTs) comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illness (two trials with healthcare workers and seven in the community). There is low certainty evidence from nine trials (3507 participants) that wearing a mask may make little or no difference to the outcome of influenza-like illness (ILI) compared to not wearing a mask (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.82 to 1.18. There is moderate certainty evidence that wearing a mask probably makes little or no difference to the outcome of laboratory-confirmed influenza compared to not wearing a mask (RR 0.91, 95% CI 0.66 to 1.26; 6 trials; 3005 participants). Harms were rarely measured and poorly reported. Two studies during COVID-19 plan to recruit a total of 72,000 people. One evaluates medical/surgical masks (N = 6000) (published Annals of Internal Medicine, 18 Nov 2020), and one evaluates cloth masks (N = 66,000). N95/P2 respirators compared to medical/surgical masks We pooled trials comparing N95/P2 respirators with medical/surgical masks (four in healthcare settings and one in a household setting). There is uncertainty over the effects of N95/P2 respirators when compared with medical/surgical masks on the outcomes of clinical respiratory illness (RR 0.70, 95% CI 0.45 to 1.10; very low-certainty evidence; 3 trials; 7779 participants) and ILI (RR 0.82, 95% CI 0.66 to 1.03; low-certainty evidence; 5 trials; 8407 participants). The evidence is limited by imprecision and heterogeneity for these subjective outcomes. The use of a N95/P2 respirator compared to a medical/surgical mask probably makes little or no difference for the objective and more precise outcome of laboratory-confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; moderate-certainty evidence; 5 trials; 8407 participants). Restricting the pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reported, but discomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies. One ongoing study recruiting 576 people compares N95/P2 respirators with medical surgical masks for healthcare workers during COVID-19. Hand hygiene compared to control Settings included schools, childcare centres, homes, and offices. In a comparison of hand hygiene interventions with control (no intervention), there was a 16% relative reduction in the number of people with ARIs in the hand hygiene group (RR 0.84, 95% CI 0.82 to 0.86; 7 trials; 44,129 participants; moderate-certainty evidence), suggesting a probable benefit. When considering the more strictly defined outcomes of ILI and laboratory-confirmed influenza, the estimates of effect for ILI (RR 0.98, 95% CI 0.85 to 1.13; 10 trials; 32,641 participants; low-certainty evidence) and laboratory-confirmed influenza (RR 0.91, 95% CI 0.63 to 1.30; 8 trials; 8332 participants; low-certainty evidence) suggest the intervention made little or no difference. We pooled all 16 trials (61,372 participants) for the composite outcome of ARI or ILI or influenza, with each study only contributing once and the most comprehensive outcome reported. The pooled data showed that hand hygiene may offer a benefit with an 11% relative reduction of respiratory illness (RR 0.89, 95% CI 0.84 to 0.95; low-certainty evidence), but with high heterogeneity. Few trials measured and reported harms. There are two ongoing studies of handwashing interventions in 395 children outside of COVID-19. We identified one RCT on quarantine/physical distancing. Company employees in Japan were asked to stay at home if household members had ILI symptoms. Overall fewer people in the intervention group contracted influenza compared with workers in the control group (2.75% versus 3.18%; hazard ratio 0.80, 95% CI 0.66 to 0.97). However, those who stayed at home with their infected family members were 2.17 times more likely to be infected. We found no RCTs on eye protection, gowns and gloves, or screening at entry ports.

AUTHORS' CONCLUSIONS

The high risk of bias in the trials, variation in outcome measurement, and relatively low compliance with the interventions during the studies hamper drawing firm conclusions and generalising the findings to the current COVID-19 pandemic. There is uncertainty about the effects of face masks. The low-moderate certainty of the evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect. The pooled results of randomised trials did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks during seasonal influenza. There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection. Hand hygiene is likely to modestly reduce the burden of respiratory illness. Harms associated with physical interventions were under-investigated. There is a need for large, well-designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, especially in those most at risk of ARIs.

Modified Small-Volume Jet Nebulizer Based on CFD Simulation and Its Clinical Outcomes in Small Asthmatic Children

The small-volume jet nebulizer (SVJN) is an aerosol device used to treat respiratory illnesses. Major problems for aerosol treatment in small children include the penetration of particles to the lower lungs due to irregular and small volume of a child patient's breath while the nebulizers used are the same models intended for adults. This adult SVJN produces a huge number of particles at a higher speed than small children can intake. To solve this problem, computational fluid dynamics (CFD) was used to redesign the device by adding 6-inch corrugated tube with 80 ml capacity (equal to one inhale capacity of a small child) into the traditional SVJN. Results revealed that the undulations of the corrugated tube were the important parts that change the direction of aerosol flow, slowing down the produced speed of aerosol up to 31.48% (mean speed = 0.37 m/s via modified SVJN vs 0.54 m/s via traditional which were close to measured results). The modified SVJN was tested for the effectiveness on how it could accommodate bronchodilator drug to the lower lungs by 3 clinical researches with 238 asthmatic children aged 1–5 years. The results revealed that the experimental group reported higher bronchodilatating effects: higher mean score of change in oxygen saturation and degree of wheezing and greater reduction in respiratory rate per minute than the control group with statistical difference (p < 0.05). Meanwhile, heart rate and physical attributes (dead volume and duration of aerosol treatment) were indifferent. Moreover, small children showed more acceptance behavior towards this modified SVJN than the traditional one. Modified SVJN might be a good choice for aerosol treatment in small children because it slows down the speed of aerosol production, makes them well spread all over the reservoir, and is ready for small children to inhale for better clinical outcomes while physical attributes are the same.

Parent experiences and information needs related to bronchiolitis: A mixed studies systematic review

OBJECTIVE

To inform evidence-based knowledge products (i.e., infographics, videos, eBooks) of relevance to parents, we systematically reviewed evidence on parent experiences and information needs related to bronchiolitis.

METHODS

We searched Medline, CINAHL, PsycINFO, and ProQuest Dissertations & Theses Global, and scanned reference lists for studies published post-2000. We appraised quality in duplicate using the Mixed Methods Appraisal Tool (MMAT) and synthesized findings narratively.

RESULTS

We retrieved 797 records and included 29; 14 (48%) met >50% of MMAT criteria. Studies predominantly enrolled mothers. Most reported quantitatively on hospitalization experiences (n = 9, 31%), treatments (n = 5, 17%), or respiratory syncytial virus (RSV) prophylaxis (n = 9, 31%). Ten (34%) studies reported on information needs; 3 contributed qualitative data. Parents could not always identify bronchiolitis symptoms. During hospitalization, parents endured guilt and anxiety. Mothers wanted to take an active role in their child's care but often felt uninvolved. Barriers to RSV prophylaxis included transportation, scheduling, and insurance issues.

CONCLUSIONS

Evidence focused primarily on hospitalization, which parents found frightening. More information is needed on home care experiences and information preferences.

PRACTICE IMPLICATIONS

Timely education and support from healthcare providers may help to alleviate parents' fears and enhance involvement in their child's care.

Nebulised hypertonic saline solution for acute bronchiolitis in infants

BACKGROUND

Airway oedema (swelling) and mucus plugging are the principal pathological features in infants with acute viral bronchiolitis. Nebulised hypertonic saline solution (≥ 3%) may reduce these pathological changes and decrease airway obstruction. This is an update of a review first published in 2008, and previously updated in 2010 and 2013.

OBJECTIVES

To assess the effects of nebulised hypertonic (≥ 3%) saline solution in infants with acute bronchiolitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily, Embase, CINAHL, LILACS, and Web of Science on 11 August 2017. We also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov on 8 April 2017.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised controlled trials using nebulised hypertonic saline alone or in conjunction with bronchodilators as an active intervention and nebulised 0.9% saline, or standard treatment as a comparator in children under 24 months with acute bronchiolitis. The primary outcome for inpatient trials was length of hospital stay, and the primary outcome for outpatients or emergency department trials was rate of hospitalisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and assessment of risk of bias in included studies. We conducted random-effects model meta-analyses using Review Manager 5. We used mean difference (MD), risk ratio (RR), and their 95% confidence intervals (CI) as effect size metrics.

MAIN RESULTS

We identified 26 new trials in this update, of which 9 await classification due to insufficient data for eligibility assessment, and 17 trials (N = 3105) met the inclusion criteria. We included a total of 28 trials involving 4195 infants with acute bronchiolitis, of whom 2222 infants received hypertonic saline.Hospitalised infants treated with nebulised hypertonic saline had a statistically significant shorter mean length of hospital stay compared to those treated with nebulised 0.9% saline (MD -0.41 days, 95% CI -0.75 to -0.07; P = 0.02, I² = 79%; 17 trials; 1867 infants) (GRADE quality of evidence: low). Infants who received hypertonic saline also had statistically significant lower post-inhalation clinical scores than infants who received 0.9% saline in the first three days of treatment (day 1: MD -0.77, 95% CI -1.18 to -0.36, P < 0.001; day 2: MD -1.28, 95% CI -1.91 to -0.65, P < 0.001; day 3: MD -1.43, 95% CI -1.82 to -1.04, P < 0.001) (GRADE quality of evidence: low).Nebulised hypertonic saline reduced the risk of hospitalisation by 14% compared with nebulised 0.9% saline among infants who were outpatients and those treated in the emergency department (RR 0.86, 95% CI 0.76 to 0.98; P = 0.02, I² = 7%; 8 trials; 1723 infants) (GRADE quality of evidence: moderate).Twenty-four trials presented safety data: 13 trials (1363 infants, 703 treated with hypertonic saline) did not report any adverse events, and 11 trials (2360 infants, 1265 treated with hypertonic saline) reported at least one adverse event, most of which were mild and resolved spontaneously.

AUTHORS' CONCLUSIONS

Nebulised hypertonic saline may modestly reduce length of stay among infants hospitalised with acute bronchiolitis and improve clinical severity score. Treatment with nebulised hypertonic saline may also reduce the risk of hospitalisation among outpatients and emergency department patients. However, we assessed the quality of the evidence as low to moderate.

Drug delivery interfaces: A way to optimize inhalation therapy in spontaneously breathing children

There are several different types of drug delivery interfaces available on the market. Using the right interface for aerosol drug delivery to children is essential for effective inhalation therapy. However, clinicians usually focus on selecting the right drug-device combination and often overlook the importance of interface selection that lead to suboptimal drug delivery and therapeutic response in neonates and pediatrics. Therefore, it is necessary to critically assess each interface and understand its advantage and disadvantages in aerosol drug delivery to this patient population. The purpose of this paper is to provide a critical assessment of drug delivery interfaces used for the treatment of children with pulmonary diseases by emphasizing advantages and problems associated with their use during inhalation therapy.

Pediatric in vitro and in silico models of deposition via oral and nasal inhalation

Respiratory tract deposition models provide a useful method for optimizing the design and administration of inhaled pharmaceutical aerosols, and can be useful for estimating exposure risks to inhaled particulate matter. As aerosol must first pass through the extrathoracic region prior to reaching the lungs, deposition in this region plays an important role in both cases. Compared to adults, much less extrathoracic deposition data are available with pediatric subjects. Recently, progress in magnetic resonance imaging and computed tomography scans to develop pediatric extrathoracic airway replicas has facilitated addressing this issue. Indeed, the use of realistic replicas for benchtop inhaler testing is now relatively common during the development and in vitro evaluation of pediatric respiratory drug delivery devices. Recently, in vitro empirical modeling studies using a moderate number of these realistic replicas have related airway geometry, particle size, fluid properties, and flow rate to extrathoracic deposition. Idealized geometries provide a standardized platform for inhaler testing and exposure risk assessment and have been designed to mimic average in vitro deposition in infants and children by replicating representative average geometrical dimensions. In silico mathematical models have used morphometric data and aerosol physics to illustrate the relative importance of different deposition mechanisms on respiratory tract deposition. Computational fluid dynamics simulations allow for the quantification of local deposition patterns and an in-depth examination of aerosol behavior in the respiratory tract. Recent studies have used both in vitro and in silico deposition measurements in realistic pediatric airway geometries to some success. This article reviews the current understanding of pediatric in vitro and in silico deposition modeling via oral and nasal inhalation.

Nebulizers for drug delivery to the lungs

INTRODUCTION

Nebulizers are the oldest modern method of delivering aerosols to the lungs for the purpose of respiratory drug delivery. While use of nebulizers remains widespread in the hospital and home setting, certain newer nebulization technologies have enabled more portable use. Varied fundamental processes of droplet formation and breakup are used in modern nebulizers, and these processes impact device performance and suitability for nebulization of various formulations.

AREAS COVERED

This review first describes basic aspects of nebulization technologies, including jet nebulizers, various high-frequency vibration techniques, and the use of colliding liquid jets. Nebulizer use in hospital and home settings is discussed next. Complications in aerosol droplet size measurement owing to the changes in nebulized droplet diameters due to evaporation or condensation are discussed, as is nebulization during mechanical ventilation.

EXPERT OPINION

While the limelight may often appear to be focused on other delivery devices, such as pressurized metered dose and dry powder inhalers, the ease of formulating many drugs in water and delivering them as aqueous aerosols ensures that nebulizers will remain as a viable and relevant method of respiratory drug delivery. This is particularly true given recent improvements in nebulizer droplet production technology.

Aerosol therapy in children: challenges and solutions

Using aerosolized medications for the treatment of children has gained importance over the years. However, aerosol drug delivery to infants and pediatrics is not an easy task as it has been influenced by many challenges. Most aerosol devices have been designed for use in adults not for children. Therefore, they require some critical assessment in device selection and often a level of adaptation for use with smaller children. It is well documented that each aerosol device and interface that have been used for the treatment of children has its own advantages and challenges in drug delivery. This paper provides a comprehensive review of dosing, drug-device combination, aerosol devices and interfaces used for drug delivery to children with pulmonary diseases. Solutions to the challenges with the aim of optimizing aerosol therapy in this patient population are also discussed.

Nebulised hypertonic saline solution for acute bronchiolitis in infants

BACKGROUND

Airway oedema and mucus plugging are the predominant pathological features in infants with acute viral bronchiolitis. Nebulised hypertonic saline solution may reduce these pathological changes and decrease airway obstruction.

OBJECTIVES

To assess the effects of nebulised hypertonic (≥ 3%) saline solution in infants with acute viral bronchiolitis.

SEARCH METHODS

We searched CENTRAL 2013, Issue 4, OLDMEDLINE (1951 to 1965), MEDLINE (1966 to April week 4, 2013), EMBASE (1974 to May 2013), LILACS (1985 to May 2013) and Web of Science (1955 to May 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs using nebulised hypertonic saline alone or in conjunction with bronchodilators as an active intervention and nebulised 0.9% saline as a comparator in infants up to 24 months of age with acute bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction and assessment of risk of bias in included studies. We conducted meta-analyses using the Cochrane statistical package RevMan 5.2. We used the random-effects model for meta-analyses. We used mean difference (MD) and risk ratio (RR) as effect size metrics.

MAIN RESULTS

We included 11 trials involving 1090 infants with mild to moderate acute viral bronchiolitis (500 inpatients, five trials; 65 outpatients, one trial; and 525 emergency department patients, four trials). All but one of the included trials were of high quality with a low risk of bias. A total of 560 patients received hypertonic saline (3% saline n = 503; 5% saline n = 57). Patients treated with nebulised 3% saline had a significantly shorter mean length of hospital stay compared to those treated with nebulised 0.9% saline (MD -1.15 days, 95% confidence interval (CI) -1.49 to -0.82, P < 0.00001). The hypertonic saline group also had a significantly lower post-inhalation clinical score than the 0.9% saline group in the first three days of treatment (day 1: MD -0.88, 95% CI -1.36 to -0.39, P = 0.0004; day 2: MD -1.32, 95% CI -2.00 to -0.64, P = 0.001; day 3: MD -1.51, 95% CI -1.88 to -1.14, P < 0.00001). The effects of improving clinical score were observed in both outpatients and inpatients. Four emergency department-based trials did not show any significant short-term effects (30 to 120 minutes) of up to three doses of nebulised 3% saline in improving clinical score and oxygen saturation. No significant adverse events related to hypertonic saline inhalation were reported.

AUTHORS' CONCLUSIONS

Current evidence suggests nebulised 3% saline may significantly reduce the length of hospital stay among infants hospitalised with non-severe acute viral bronchiolitis and improve the clinical severity score in both outpatient and inpatient populations.

Hood nebulization: effects of head direction and breathing mode on particle inhalability and deposition in a 7-month-old infant model

BACKGROUND

Aerosol drug delivery to infants is a strong function of their behavior. Infants can be active during medication administration, changing head position or breathing mode. The objective was to evaluate the influence of the head direction and breathing mode on the hood drug delivery in a 7-month-old girl airway model by using an approach that couples imaging with computational fluid dynamics (CFD). Three head directions, i.e., face up, face side, and sitting (face front), and two breathing modes, i.e., oronasal and nasal breathing, were studied.

METHODS

The face-airway model was developed from computed tomography scans of a 7-month-old girl. Respiratory airflows and particle transport were simulated with the low Reynolds number κ-ω turbulence model and Lagrangian tracking approach. Three pharmaceutical aerosol sizes (1, 2.5, and 5 μm) via hood nebulization were considered under quiet breathing conditions (5 L/min).

RESULTS

Both head direction and breathing mode can noticeably affect aerosol inhalability and lung delivery efficiency. A maximum of 20% difference in inhalability is observed among the three head positions. Facial-ocular depositions are predominantly influenced by head position, but not breathing mode. The facial-ocular deposition rate with the face-up position is about threefold that with the sitting position for 5-μm particles. Nasal breathing gives about 17.8% lower lung deposition and about 65% higher facial-ocular deposition than the oronasal breathing.

CONCLUSION

The face-side position has less facial-ocular deposition than the face-up position, while still achieving similar lung delivery efficiency. Because aerosols deposited around the eyes may cause irritation to the eyes, the face-side position appears to be a better option than the face-up position for comfort and safety reasons.

Guidelines for aerosol devices in infants, children and adults: which to choose, why and how to achieve effective aerosol therapy

Multiple types of aerosol devices are commonly used for the administration of medical aerosol therapy to patients with pulmonary diseases. All of these devices have been shown to be effective in trials where they are used correctly. However, failure to operate any of these devices properly has been associated with poor clinical response and limited patient adherence to therapy. Therefore, the selection of the best aerosol device for the individual patient is very important for optimizing the results of medical aerosol therapy. This article presents the rationale for selecting the most appropriate aerosol device to administer inhaled drugs in specific patient populations, with emphasis on patient-, drug-, device- and environment-related factors and with a comparison between the available devices. The following recommendations for the selection of the 'best' aerosol device for each patient population are intended to help clinicians gain a clear understanding of the specific issues and challenges so that they can optimize aerosol drug delivery and its therapeutic outcomes in patients.

Care of infants and children with bronchiolitis: a systematic review

Bronchiolitis is the most frequent cause of hospitalization in the infant population. Management varies widely, and the efficacy of many routinely implemented therapies is not supported by evidence. The purpose of the systematic review was to identify the best evidence available regarding the care of infants and children with bronchiolitis. A two-phase literature search was performed, and 20 publications were appraised. An abundance of evidence regarding management of bronchiolitis was revealed resulting in numerous recommendations. Use of a clinical pathway is proposed as a possible solution for moving this evidence into practice.

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a global threat. Antiviral drugs and vaccinations may be insufficient to prevent their spread.

OBJECTIVES

To review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

SEARCH STRATEGY

We searched The Cochrane Library, the Cochrane Central Register of Controlled Trials (CENTRAL 2010, Issue 3), which includes the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to October 2010), OLDMEDLINE (1950 to 1965), EMBASE (1990 to October 2010), CINAHL (1982 to October 2010), LILACS (2008 to October 2010), Indian MEDLARS (2008 to October 2010) and IMSEAR (2008 to October 2010).

SELECTION CRITERIA

In this update, two review authors independently applied the inclusion criteria to all identified and retrieved articles and extracted data. We scanned 3775 titles, excluded 3560 and retrieved full papers of 215 studies, to include 66 papers of 67 studies. We included physical interventions (screening at entry ports, isolation, quarantine, social distancing, barriers, personal protection, hand hygiene) to prevent respiratory virus transmission. We included randomised controlled trials (RCTs), cohorts, case-controls, before-after and time series studies.

DATA COLLECTION AND ANALYSIS

We used a standardised form to assess trial eligibility. We assessed RCTs by randomisation method, allocation generation, concealment, blinding and follow up. We assessed non-RCTs for potential confounders and classified them as low, medium and high risk of bias.

MAIN RESULTS

We included 67 studies including randomised controlled trials and observational studies with a mixed risk of bias. A total number of participants is not included as the total would be made up of a heterogenous set of observations (participant people, observations on participants and countries (object of some studies)). The risk of bias for five RCTs and most cluster-RCTs was high. Observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis. The highest quality cluster-RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Benefit from reduced transmission from children to household members is broadly supported also in other study designs where the potential for confounding is greater. Nine case-control studies suggested implementing transmission barriers, isolation and hygienic measures are effective at containing respiratory virus epidemics. Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. N95 respirators were non-inferior to simple surgical masks but more expensive, uncomfortable and irritating to skin. Adding virucidals or antiseptics to normal handwashing to decrease respiratory disease transmission remains uncertain. Global measures, such as screening at entry ports, led to a non-significant marginal delay in spread. There was limited evidence that social distancing was effective, especially if related to the risk of exposure.

AUTHORS' CONCLUSIONS

Simple and low-cost interventions would be useful for reducing transmission of epidemic respiratory viruses. Routine long-term implementation of some measures assessed might be difficult without the threat of an epidemic.

Aerosol therapy in infants and toddlers: past, present and future

Infants and toddlers are a unique subpopulation with regard to aerosol therapy. There are various anatomical, physiological and emotional factors peculiar to this age group that present significant difficulties and challenges for aerosol delivery. Most studies on the factors determining lung deposition of therapeutic aerosols are based on data from adults or older children, which cannot simply be extrapolated directly to infants. The present review describes why infants/toddlers are very different with respect to two major issues - namely their anatomy/physiology and their behavior. We suggest possible solutions and future research directions aimed at improving clinical outcomes of aerosol therapy in this age group.

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a world-wide threat. Antiviral drugs and vaccinations may be insufficient to prevent catastrophe.

OBJECTIVES

To systematically review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2); MEDLINE (1966 to May 2009); OLDMEDLINE (1950 to 1965); EMBASE (1990 to May 2009); and CINAHL (1982 to May 2009).

SELECTION CRITERIA

We scanned 2958 titles, excluded 2790 and retrieved the full papers of 168 trials, to include 59 papers of 60 studies. We included any physical interventions (isolation, quarantine, social distancing, barriers, personal protection and hygiene) to prevent transmission of respiratory viruses. We included the following study designs: randomised controlled trials (RCTs), cohorts, case controls, cross-over, before-after, and time series studies.

DATA COLLECTION AND ANALYSIS

We used a standardised form to assess trial eligibility. RCTs were assessed by: randomisation method; allocation generation; concealment; blinding; and follow up. Non-RCTs were assessed for the presence of potential confounders, and classified into low, medium, and high risks of bias.

MAIN RESULTS

The risk of bias for the four RCTs, and most cluster RCTs, was high. The observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis.The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. Six case-control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that N95 respirators were superior to simple surgical masks, but were more expensive, uncomfortable, and caused skin irritation. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. Global measures, such as screening at entry ports, were not properly evaluated. There was limited evidence that social distancing was effective especially if related to the risk of exposure.

AUTHORS' CONCLUSIONS

Many simple and probably low-cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long-term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.

Medical treatment of lung collapse in children

This study was aimed to establish non-invasive (medical) treatment of lung collapse for children who are admitted to PICU of Tabriz Children's Hospital. During a period of 48 months (from March 2004 to February 2008), an interventional pre-experimental study carried out on 90 children suffering from lung collapse who received non-invasive treatment; which mainly consists of postural drainage, chest physiotherapy and inhalation of aerosols (fluid as floating droplets in air) and bronchodilators. Eighty six out of 90 studied patients (94.5%) with the average age of 22 months, responded to this treatment within the average duration of 3.4 days, as collapsed area of lung reexpanded. Because of simplicity and easy availability of this method of treatment and also its efficacy and scientific base; it can substitute bronchoscopic treatment and its usage be generalized to small hospitals.

Cochrane Review: Interventions for the interruption or reduction of the spread of respiratory viruses

Background

Viral epidemics or pandemics such as of influenza or severe acute respiratory syndrome (SARS) pose a significant threat. Antiviral drugs and vaccination may not be adequate to prevent catastrophe in such an event.

Objectives

To systematically review the evidence of effectiveness of interventions to interrupt or reduce the spread of respiratory viruses (excluding vaccines and antiviral drugs, which have been previously reviewed).

Search strategy

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, issue 4); MEDLINE (1966 to November 2006); OLDMEDLINE (1950 to 1965); EMBASE (1990 to November 2006); and CINAHL (1982 to November 2006).

Selection criteria

We scanned 2300 titles, excluded 2162 and retrieved the full papers of 138 trials, including 49 papers of 51 studies. The quality of three randomised controlled trials (RCTs) was poor; as were most cluster RCTs. The observational studies were of mixed quality. We were only able to meta‐analyse case‐control data. We searched for any interventions to prevent viral transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection and hygiene). Study design included RCTs, cohort studies, case‐control studies, cross‐over studies, before‐after, and time series studies.

Data collection and analysis

We scanned the titles, abstracts and full text articles using a standardised form to assess eligibility. RCTs were assessed according to randomisation method, allocation generation, concealment, blinding, and follow up. Non‐RCTs were assessed for the presence of potential confounders and classified as low, medium, and high risk of bias.

Main results

The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. The six case‐control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. The lack of proper evaluation of global measures such as screening at entry ports and social distancing prevent firm conclusions about these measures.

Authors' conclusions

Many simple and probably low‐cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long‐term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.

Plain language summary

Interventions to interrupt or reduce the spread of respiratory viruses

Although respiratory viruses usually only cause minor disease, they can cause epidemics. Approximately 10% to 15% of people worldwide contract influenza annually, with attack rates as high as 50% during major epidemics. Global pandemic viral infections have been devastating because of their wide spread. In 2003 the severe acute respiratory syndrome (SARS) epidemic affected ˜8,000 people, killed 780, and caused an enormous social and economic crisis. A new avian influenza pandemic caused by the H5N1 strain might be more catastrophic. Single measures (particularly the use of vaccines or antiviral drugs) may be insufficient to interrupt the spread.

We found 51 studies including randomised controlled trials (RCTs) and observational studies with a mixed risk of bias.

Respiratory virus spread might be prevented by hygienic measures around younger children. These might also reduce transmission from children to other household members. Implementing barriers to transmission, isolation, and hygienic measures may be effective at containing respiratory virus epidemics. There was limited evidence that (more uncomfortable and expensive) N95 masks were superior to simple ones. Adding virucidals or antiseptics to normal handwashing is of uncertain benefit. There is insufficient evaluation of global measures such as screening at entry ports and social distancing.

Nebulized hypertonic saline solution for acute bronchiolitis in infants

BACKGROUND

Airway edema and mucus plugging are the predominant pathological features in infants with acute viral bronchiolitis. Nebulized hypertonic saline solution may reduce these pathological changes and decrease airway obstruction.

OBJECTIVES

To assess the effects of nebulized hypertonic saline solution in infants with acute viral bronchiolitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, issue 4), which contains the Cochrane Acute Respiratory Infections Group Specialized Register; OLDMEDLINE (1951 to 1965); MEDLINE (1966 to November 2007); EMBASE (1974 to November 2007); and LILACS (November 2007).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs using nebulized hypertonic saline alone or in conjunction with bronchodilators as an active intervention in infants up to 24 months of age with acute bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors (ZL, MRA) independently performed data extraction and study quality assessment. We pooled the data from individual trials using the Cochrane statistical package Review Manager (RevMan).

MAIN RESULTS

We included four trials involving 254 infants with acute viral bronchiolitis (189 inpatients and 65 outpatients) in this review. Patients treated with nebulized 3% saline had a significantly shorter mean length of hospital stay compared to those treated with nebulized 0.9% saline (mean difference (MD) -0.94 days, 95% CI -1.48 to -0.40, P = 0.0006). The 3% saline group also had a significantly lower post-inhalation clinical score than the 0.9% saline group in the first three days of treatment (day 1: MD -0.75, 95% CI -1.38 to -0.12, P = 0.02; day 2: MD -1.18, 95% CI -1.97 to -0.39, P = 0.003; day 3: MD -1.28, 95% CI -2.57 to 0.00, P = 0.05). The effect of nebulized hypertonic saline in improving clinical score was greater among outpatients than inpatients. No adverse events related to 3% saline inhalation were reported.

AUTHORS' CONCLUSIONS

Current evidence suggests nebulized 3% saline may significantly reduce the length of hospital stay and improve the clinical severity score in infants with acute viral bronchiolitis.

Inhaled furosemide in hospitalized infants with viral bronchiolitis: a randomized, double-blind, placebo-controlled pilot study

OBJECTIVE

To evaluate the short and long-term clinical effects and the treatment-feasibility of inhaled-furosemide (IF) as compared with placebo via hood in hospitalized infants with viral-bronchiolitis (VB).

STUDY-DESIGN

A randomized, double-blind, placebo-controlled pilot-study was performed in previously healthy infants (0-12 months). Enrolled infants were randomized to receive either IF (2 mg/kg), or placebo nebulized by hood three times daily throughout the hospitalization. Clinical assessment (respiratory distress assessment instrument [RDAI]) was performed before, 30 and 60 min after the 1st daily inhalation. The short-term effects were evaluated by the RDAI, respiratory assessment change score (RACS) and oxygen requirement and the long-term effects by time to be weaned off oxygen, time to full enteral feeding, length of stay, and "ready to discharge" time.

RESULTS

Both groups (16 infants each) had comparable characteristics at study entry. Mean (+/-SD) age was 72 +/- 43 days, and 29/32 infants were RSV positive. Oxygen requirement (FiO(2)) decreased significantly at 30 min post-inhalation (30 +/- 9.2% to 26 +/- 7.1%, P < 0.05) only in the IF group. RACSs and long-term effects of both groups were comparable. Analysis of IF particles generated by the hood-nebulizer demonstrated that 36% and 49% of the particles were <3 and 5 microm, respectively. No side effects were observed during IF treatment.

CONCLUSION

Based on our pilot study, IF has no significant clinical effects in hospitalized infants with VB. IF via hood seems to be feasible and safe.

Interventions for the interruption or reduction of the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics such as of influenza or severe acute respiratory syndrome (SARS) pose a significant threat. Antiviral drugs and vaccination may not be adequate to prevent catastrophe in such an event.

OBJECTIVES

To systematically review the evidence of effectiveness of interventions to interrupt or reduce the spread of respiratory viruses (excluding vaccines and antiviral drugs, which have been previously reviewed).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4); MEDLINE (1966 to November 2006); OLDMEDLINE (1950 to 1965); EMBASE (1990 to November 2006); and CINAHL (1982 to November 2006).

SELECTION CRITERIA

We scanned 2300 titles, excluded 2162 and retrieved the full papers of 138 trials, including 49 papers of 51 studies. The quality of three randomised controlled trials (RCTs) was poor; as were most cluster RCTs. The observational studies were of mixed quality. We were only able to meta-analyse case-control data. We searched for any interventions to prevent viral transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection and hygiene). Study design included RCTs, cohort studies, case-control studies, cross-over studies, before-after, and time series studies.

DATA COLLECTION AND ANALYSIS

We scanned the titles, abstracts and full text articles using a standardised form to assess eligibility. RCTs were assessed according to randomisation method, allocation generation, concealment, blinding, and follow up. Non-RCTs were assessed for the presence of potential confounders and classified as low, medium, and high risk of bias.

MAIN RESULTS

The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. The six case-control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. The lack of proper evaluation of global measures such as screening at entry ports and social distancing prevent firm conclusions about these measures.

AUTHORS' CONCLUSIONS

Many simple and probably low-cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long-term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.