Nebulized normal saline, which is often used as a placebo in clinical trials evaluating therapies for acute viral bronchiolitis, may be an active treatment for this condition, according to the findings of a recently published systematic review and meta-analysis. 

As consistent clinical improvement in patients receiving nebulized normal saline has been observed in acute viral bronchiolitis therapeutic trials, study authors aimed to determine whether it should be considered an active treatment for this condition. “We undertook a systematic review and meta-analysis of randomized clinical trials in acute viral bronchiolitis using nebulized [normal saline] with 2 objectives: to compare nebulized [normal saline] with other forms of placebo (eg, nonnebulized placebo or sham nebulization) and to estimate the association of nebulized [normal saline] with short-term physiologic measures of respiratory status in randomized clinical trials in which it was used as the placebo,” the authors stated. 

The analysis included a total of 29 studies (n=1583). The study authors reported that, although no differences were seen in the standardized mean differences for respiratory rate or oxygen saturation when comparing nebulized normal saline with another placebo, a difference in respiratory scores which favored nebulized normal saline by -0.9 points was observed 60 minutes post-treatment (3 studies; 95% CI, -1.2, -0.6; P <.001). 

Additional analysis revealed that, after nebulized normal saline, the standardized mean difference in respiratory score was -0.7 (25 studies; 95% CI, -0.7, -0.6; I2=62%) while the weighted mean difference in respiratory scores was -1.6 points when using a consistent scale (13 studies; 95% CI, -1.9, -1.3; I2=72%). The study authors also reported that, after nebulized normal saline, the weighted mean differences in respiratory rate and oxygen saturation were found to be -5.5 breaths per minute (17 studies; 95% CI, -6.3, -4.6; I2=24%) and -0.4% (23 studies; 95% CI, -0.6, -0.2; I2=79%), respectively. 

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“Nebulized normal saline may not be an inert placebo for patients with bronchiolitis and should be further studied to establish the clinical significance of any potential treatment outcome,” the authors concluded.

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