Effect Sizes in Bronchiolitis children with Respiratory Distress: HFNC vs Nasal Oxygen Therapy—A Prospective Cohort Study

Background: Currently, there are neither clinical features nor universally validated respiratory distress severity scores that are useful in all clinical settings, which can reliably distinguish bronchiolitis children needing high-flow nasal cannula (HFNC) therapy from those who can be managed with nasal oxygen. This clinical gap is due in part to limited data on the effect sizes of specific clinical features and that of respiratory severity scores in present predictive models. Methods: This prospective cohort study’s aim was to evaluate the effect sizes of certain clinical parameters, the Respiratory Severity Score (RSS), and the Modified Comfort Score (MCS) in children with bronchiolitis receiving either HFNC or nasal oxygen therapy. A consecutive sample of sixty-eight children aged 1–36 months admitted to the Pediatric Intensive Care Unit (PICU) at Sri Ramachandra Children and Dental Hospital, Guntur, between September and December 2024 were studied. Data of demographic, and clinical characteristics, including respiratory severity scores (RSS and MCS) were collected at admission (0 hours) and at 6, 12, and 24 hours after starting oxygen therapy. Results: Bronchiolitis children started on HFNC had significantly lower oxygen saturation, higher respiratory and heart rates, and higher respiratory distress scores (RSS and MCS) at admission compared to those managed with nasal oxygen. Both groups showed progressive improvement in the parameters during the 24-hour observation period. The differences in the RSS and MCS between the two groups is not clinically significant by 6–12 hours after therapy, when the effect of baseline RSS was adjusted. The oxygen therapy method was not predicting the 6 hours SpO2, RR, and HR when their baseline values were controlled. Conclusion: This study highlights the need for developing reliable tools to predict the need for HFNC in specific group of bronchiolitis children. Shown effect sizes of this study provide preliminary data for future research aimed to develop predictive models with greater power and better generalisability. Further studies with large samples, RCT designs and with longer follow up of observations help delineate the characteristics at admission of bronchiolitis children which help development of better predictive tools.