EBM Review: 7% hypertonic saline in acute bronchiolitis: a randomized controlled trial

Jacobs JD, Foster M, Wan J, Pershad J. 7% hypertonic saline in acute bronchiolitis: a randomized controlled trial. Pediatrics. 2014 Jan;133(1):e8-13.

Full-text for Children’s and Emory users.

BACKGROUND: Research suggests that hypertonic saline (HS) may improve mucous flow in infants with acute bronchiolitis. Data suggest a trend favoring reduced length of hospital stay and improved pulmonary scores with increasing concentration of nebulized solution to 3% and 5% saline as compared with 0.9% saline mixed with epinephrine. To our knowledge, 7% HS has not been previously investigated.

METHODS: We conducted a prospective, double-blind, randomized controlled trial in 101 infants presenting with moderate to severe acute bronchiolitis. Subjects received either 7% saline or 0.9% saline, both with epinephrine. Our primary outcome was a change in bronchiolitis severity score (BSS), obtained before and after treatment, and at the time of disposition from the emergency department (ED). Secondary outcomes measured were hospitalization rate, proportion of admitted patients discharged at 23 hours, and ED and inpatient length of stay.

RESULTS: At baseline, study groups were similar in demographic and clinical characteristics. The decrease in mean BSS was not statistically significant between groups (2.6 vs 2.4 for HS and control groups, respectively). The difference between the groups in proportion of admitted patients (42% in HS versus 49% in normal saline), ED or inpatient length of stay, and proportion of admitted patients discharged at 23 hours was not statistically significant.

CONCLUSIONS: In moderate to severe acute bronchiolitis, inhalation of 7% HS with epinephrine does not appear to confer any clinically significant decrease in BSS when compared with 0.9% saline with epinephrine.

Reviewed by:

Natalie Metzig, MD Natalie Metzig, MD

Tiffany Vinet, MD Tiffany Bell Vinet, MD

Main points

  • Assess effectiveness of hypertonic saline 7% on lowering clinical severity of illness, admission rate or length of stay
  • Previous data suggest these are lower with 3% and 5% hypertonic saline, no studies evaluating 7%
  • Prospective, double-blind, randomized controlled trial
  • 101 infants with moderate to severe acute bronchiolitis being treated in ED were included in study
  • Given HTS 7% w/ epinephrine (52) or 0.9% saline with epinephrine (49)
  • Primary outcome was bronchiolitis severity score (BSS) before and after treatment
  • Secondary outcomes were hospitalization rate, proportion of admitted patients d/c’ed at 23 hours, and length of ED and inpatient stays
  • Decrease in mean BSS was not statistically significant between groups
  • Proportion of admitted patients, ED or inpatient length of stay, and proportion discharged at 23 hours was not statistically significant between groups


  • Bronchiolitis is the most common lower respiratory infection of infants and young children
  • Annual inpatient disease burden exceeds cost of any respiratory disease in US in children < 2 yo
  • Many treatments have been investigated, and only few have been shown to be effective
  • Mainstay of treatment is supportive care with oxygen as needed and hydration
  • Currently, corticosteroids and bronchodilators not recommended
  • Some evidence epinephrine may be more efficacious compared to bronchodilators
  • Nebulized HTS shown promise
  • All studies to date on 3% HTS have shown it to be safe and reduced length of hospital stay and improve clinical severity score


  • BSS is an objective tool that has been previously validated and used modified BSS
    • Modified BSS has been used in this institution since 2006
    • Assessed correlation before beginning study and correlation was high
  • 2 groups were similar in all clinical and historical characteristics
    • Difference in proportion who received albuterol or supplemental O2 was not statistically significant
  • Randomized controlled trial, double-blind study

Limitations and Future Studies

  • Use of 7% HS with racemic epinephrine ONLY
    • Study results can only be interpreted as HTS does not show significant effect when used with racemic epinephrine
    • Does interaction play a role in outcome of study?
    • Would it work alone? Would it work with another medication such as albuterol?
  • Frequency of treatment 
    • Q6H therapy from admission, throughout stay (what if Q4H?)
  • Severity of illness
    • (most were moderately ill, excluded most severely ill patients)
    • Would need a large-scale study to capture severely ill patients
    • Possibly separate trials based on severity
    • Can use data from this study to determine appropriate sample size for additional studies
  • Natural history of the disease
    • Average patient was on day 3 of illness.
    • Would it help to treat sooner? Were they getting better on their own?
    • Future study could look at patients on day 1 or 2 of illness.

Clinical Significance

  • Not much changed.
    • Supportive care is still primary management (airway management and rehydration as needed)
    • No evidence 7% is better when used with racemic epinephrine,
    • You can continue with 3-5% if use Hypertonic Saline as deemed fit.

Final Summary

  • Mainstay of bronchiolitis management is supportive care
  • Some evidence that 3%-5% hypertonic saline nebs may decrease BSS and hospital length of stay
  • Research on 7% HTS is limited. This study suggests no significant improvement of patients received 7% HTS compared to normal saline when used with epinephrine.
  • Further research into Hypertonic Saline nebs is needed in the future.

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