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. To assess the effects of nebulised hypertonic (≥ 3%) saline solution in infants
with acute bronchiolitis. 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. 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. 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. 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. 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. Is
hypertonic saline solution via nebuliser effective and safe for infants with acute
bronchiolitis? Review question Is hypertonic saline solution via nebuliser effective
and safe for the treatment of infants with acute bronchiolitis, compared to normal
saline solution? Background Acute bronchiolitis is the most common lower respiratory
tract infection in children aged up to two years. Bronchiolitis occurs when small
structures (bronchioles) leading to the lungs become infected, causing inflammation,
swelling, and mucus production. This makes breathing difficult, especially in very
young children, who develop coughs and wheezing. Because bronchiolitis is usually
caused by a virus, drug treatment is usually not effective. Hypertonic saline (sterile
salt water solution) breathed in as a fine mist using a nebuliser may help relieve
wheezing and breathing difficulty. We compared nebulised hypertonic (≥ 3%) saline
solution with nebulised normal (0.9%) saline for infants with acute bronchiolitis.
This is an update of a review previously published in 2008, 2010, and 2013. Search
date 11 August 2017 Study characteristics We identified 26 new studies in this update,
of which 9 await assessment and 17 trials (N = 3105) were added. We included a total
of 28 trials involving 4195 infants with acute bronchiolitis. Key results Nebulised
hypertonic saline may reduce hospital stay by 10 hours in comparison to normal saline
for infants admitted with acute bronchiolitis. We found that 'clinical severity scores',
which are used by doctors to assess patient health, for children treated as outpatients
or in hospital improved when administered nebulised hypertonic saline compared to
normal saline. Nebulised hypertonic saline may also reduce the risk of hospitalisation
by 14% among children treated as outpatients or in the emergency department. We found
only minor and spontaneously resolved adverse effects from the use of nebulised hypertonic
saline when given with treatment to relax airways (bronchodilators). Reductions in
hospital stay were smaller than previously thought. However, an average reduction
of 10 hours in the length of hospital stay for infants is significant because bronchiolitis
usually has a short duration. Nebulised hypertonic saline appears to be safe and widely
available at low cost. Quality of evidence The quality of the evidence was low to
moderate: there were inconsistencies in results among trials and risk of bias in some
trials. Future large trials are therefore needed to confirm the benefits of nebulised
hypertonic saline for children with bronchiolitis treated as outpatients and in hospital.