Which concentration of hypertonic saline for bronchiolitis?

A comparison of 3 different concentrations of nebulized saline with epinephrine in infants with acute bronchiolitis showed that 5% saline may be superior to 0.9% normal saline for early outpatient treatment.

Investigators in Qatar conducted a trial in 171 infants (median age, 3.1 months) with viral bronchiolitis who were assigned to receive 5%, 3%, or 0.9% (usual care) saline with epinephrine every 4 hours. At 48 hours, the primary outcome time point, the mean bronchiolitis severity scores for the 5% group and for the 0.9% group were significantly different: 3.69 and 4.12, respectively (P=.04). The mean severity score for the 3% saline group was intermediate at 4.00. A consistent trend was seen favoring 5% saline starting about 8 hours after randomization and continuing to 72 hours.

The rate of revisits to the pediatric emergency center in the 7 days after discharge (median stay, <2 days for all 3 groups) was high and similar for the 3 treatment groups: 61% for the 5% saline group, 59% for the 3% saline group, and 63% for the 0.9% saline group (P=.91). Antibiotic use was similar in the 3 groups, and no infants required corticosteroids. There were no safety concerns associated with any of the 3 concentrations (Al-Ansari K, et al. J Pediatr. 2010;157[4]:630-634).

This is not the definitive study of this topic but another in a series of observations suggesting that hypertonic saline (5% here, 3% in other studies) may have a role in the treatment of bronchiolitis. Patients treated with nebulized 5% saline with epinephrine in this study improved more than those given epinephrine in 0.9% saline. However, the improvement was small, only apparent after several hours, and perhaps not clinically significant. We are still waiting for the big multicenter study that sorts out once and for all the roles of beta agonists, steroids, nebulized hypertonic saline, or some combination of agents for treatment of bronchiolitis. A study that shows some new treatment with clear and rapid effect on this disease would be even better. -Michael Burke, MD