Chowdhury 2013.
| Methods | Prospective, double‐blind, multi‐centre, randomised controlled trial | |
| Participants | 281 infants (< 1 year old) with clinical bronchiolitis requiring admission for hypoxia or respiratory distress. The study was carried out in the bronchiolitis seasons Criteria for inclusion: diagnosis of bronchiolitis and need of hospitalisation for respiratory distress or hypoxia (SpO2 < 93% in room air) Baseline characteristics of subjects at presentation, median (IQRs): Age, wk 10.90 (5.85 to 25.50) versus 17.70 (6.80 to 29.40) Weight, kg 5.65 (4.34 to 7.70) versus 5.70 (4.40 to 7.70) RSV+, % 79.3 versus 82.3 Modified Woods Clinical Asthma Score (m‐WCAS, maximum score of 11, median interquartile): 3.0 (2.0 to 3.0) versus 3.0 (2.0 to 4.0) Respiratory rate, breaths per min 56.0 (44.0 to 62.0) versus 53.0 (47.0 to 63.5) SpO2 in room air, % 92.0% (89.0 to 95.0) versus 91.0% (89.0 to 94.0) | |
| Interventions | Patients were randomised to receive via facemask 10 L/min (nasal cannula 3L/min, if facemask intolerant) or nCPAP 6 cm H2O if severe respiratory distress: HeOx = Heliox21 (79% He + 21% O2) ± additional O2OR AirOx = Medical Air (79% N2 + 21% O2) ± additional O2, with humidification of the gases | |
| Outcomes | Primary endpoint was length of treatment (LoT) required to alleviate hypoxia and respiratory distress Secondary endpoints were proportion of participants needing nCPAP; nCPAP (LoT); and change in respiratory distress score | |
| Notes | In the clinical score used, 2 variables are redundant: pulse oxymetry and cyanosis | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐stratified block randomisation |
| Allocation concealment (selection bias) | Low risk | Patients were enrolled and allocated by telephone to Gas A or B |
| Blinding (performance bias and detection bias) All outcomes | Unclear risk | The labelling of intervention gases as cylinder A and B potentially exposed the study to assessment bias |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Consent was obtained for 319 participants who were randomised and enrolled into the study. Authors reported that analysis was performed by intention‐to‐treat, but provided results from a subgroup of 281 infants 3 participants were excluded (2 withdrawal of consent and 1 screening failure). An additional 35 participants were excluded because of protocol violation, consent withdrawal, screening failure, hospital clinician's decision or premature disruption of therapy |
| Selective reporting (reporting bias) | Low risk | All outcome results were reported |
| Other bias | Low risk | |