Clinical Features of Patients With Bronchiolitis Prior to the Initiation of Noninvasive Respiratory Support.

Background: Effective management of infants hospitalized with bronchiolitis depends on clinician assessment of disease severity. Although environmental and demographic risk factors help identify severe cases, there is limited research on specific clinical and physiological characteristics associated with respiratory deterioration. This study aimed to identify physiologic variables and clinical parameters associated with respiratory deterioration in hospitalized infants with bronchiolitis. Methods: A single-center retrospective cohort study included previously healthy infants <2 years of age hospitalized for bronchiolitis. The primary outcome measure, deterioration, was defined as respiratory distress requiring noninvasive (including high-flow nasal cannula) or invasive respiratory support within 48 h of admission. A multivariable logistic regression analysis with preselected factors was used to assess the odds of deterioration. Variables included sex, age, affect and behavior, nasopharyngeal suctioning, number, location of retractions, S_pO2/F_IO2 (S/F ratio), breathing frequency, pulse rate, and respiratory severity score. A secondary analysis assessed retraction locations. Results: Of the 584 eligible patients, 154 (26%) experienced a deterioration event and required noninvasive or invasive respiratory support. Respiratory score (odds ratio [OR] 1.9 [95% CI 1.5-2.4]), total number of retractions (OR: 2.5 [95% CI 1.6-3.8]), S/F ratio (OR: 1.0 [95% CI 0.99-0.998), pulse rate (OR: 1.0 [95% CI 1.0-1.1]), nasopharyngeal suctioning (OR: 5.5 [95% CI 2.6-11.7]), and positive affect and behavior descriptors (OR: 0.3 [95% CI 0.1-0.7]) were associated with deterioration. Age, sex, negative affect and behavior descriptors, and breathing frequency were not statistically significant. Conclusions: These variables may be used to design predictive algorithms that alert clinicians of impending respiratory deterioration in infants with bronchiolitis.