We read with interest the article on use of nasal continuous positive airway pressure (CPAP) in bronchiolitis by Lal, et al. [1]. We have few comments related to this article:

First, the authors have considered respiratory rate at one hour of treatment as primary outcome. As we know that the signs and symptoms of bronchiolitis may vary even from minute to minute, a change in respiratory rate at one hour may not have any clinical importance [2]. Moreover, it has been reported that there is inter-observer variability in assessment of respiratory rate in infants. Ideally quality control measures like video recording of respiratory rate, which is feasible, should be taken to avoid subjective bias of primary outcome [3].

Second, outcome as well as complications of CPAP will also depend on flow rate and peak end expiratory pressure (PEEP). Authors have not mentioned about flow rate and PEEP in their study [4].

Third, authors have used Silverman-Andersen score – that is primarily used to assess respiratory distress in premature baby – and Modified Pediatric Society of New Zealand Severity Score. These scores have not been validated as an outcome measure in infant with bronchiolitis [5].

Finally, the information about weight, length and Z-scores are missing, which are important baseline characteristics. In table II, the value of standard deviation are greater than the mean value. It will be better if these data would have been presented as median and interquartile range.

1. Lal SN, Kaur J, Anthwal P, Goyal K, Bahl P, Puliyel JM. Nasal continuous positive airway pressure in bronchiolitis: A randomized controlled trial. Indian Pediatr. 2018; 55:27-30.

2. Prinsen CA, Vohra S, Rose MR, Boers M, Tugwell P, Clarke M, et al. How to select outcome measurement instruments for outcomes included in a "Core Outcome Set" - a practical guideline. Trials. 2016;17:449.

3. Muro F, Mosha N, Hildenwall H, Mtei F, Harrison N, Schellenberg D, et al. Variability of respiratory rate measurements in children suspected with non-severe pneumonia in north-east Tanzania. Trop Med Int Health. 2017;22:139-47.

4. Sinha IP, McBride AKS, Smith R, Fernandes RM. CPAP and high-flow nasal cannula oxygen in bronchiolitis. Chest. 2015;148:810-23.