Inhaled nitric oxide in acute bronchiolitis: A systematic review and meta-analysis.

OBJECTIVE: Until date there is lack of effective therapies in acute bronchiolitis in infants. The aim was to analyze inhaled nitric oxide efficacy in acute bronchiolitis.

DESIGN: Systematic review and meta-analysis of randomized controlled trials.

SETTING: Pediatric specialized healthcare.

PATIENTS: All infants (age less than 2 years) having acute bronchiolitis, which requires emergency room visit or hospitalization.

INTERVENTION: Inhaled nitric oxide.

MAIN OUTCOME MEASURES: Need for intensive care unit admission. Secondary outcomes were length of hospital stay and adverse events. Risk ratios (RR) and mean differences with 95% confidence intervals (CI) calculated by random-effects DerSimonian and Laird inverse variance method. Peto Odds ratios were used for rare outcomes. Evidence certainty assessed according to GRADE.

RESULTS: 186 studies were screened and three included for analysis. Two had low risk of bias and one had some concerns. Three studies (166 infants) analyzed length of hospital stay and the duration was -11.3 h (CI: -26.8 to +4.2 h) shorter in the nitric oxide group. Evidence certainty was ranked as low. Overall adverse event rates were similar (3 studies, 166 infants, RR: 0.94, CI: 0.70-1.26), but treatment related harms were more common in nitric oxide group (2 studies, 98 infants, OR: 3.86, CI: 1.04-14.40). Evidence certainty in both was rated as low.

CONCLUSIONS: Low certainty evidence suggests that inhaled nitric oxide does not reduce length of hospital stay but may have higher rate of treatment associated harms. Future studies with larger sample sizes are needed to better estimate both the efficacy and adverse events.