35 - Factors Associated with Mild Bronchiolitis in Young Infants

Poster Number: 35
Publication Number: 35.111

Son H. McLaren, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States; Ying (Shelly) Qi, Massachusetts General Hospital, Boston, MA, United States; Janice A. Espinola, Massachusetts General Hospital, Boston, MA, United States; Jonathan Mansbach, Boston Children's Hospital, Boston, MA, United States; Peter Dayan, Columbia University, Hastings on Hudson, NY, United States; Carlos A. Camargo, MGH/Harvard, Boston, MA, United States

Background: Bronchiolitis within the first 2-3 months of life has been identified as a risk factor for more severe illness, which may heighten concerns for clinical deterioration and potentially lead to unnecessary hospitalizations in this age group.

Objective: We aimed to identify characteristics associated with mild bronchiolitis in infants ≤90 days presenting to the emergency department (ED).

Design/Methods: We conducted a secondary analysis of infants ≤90 days old with bronchiolitis using data from the 25th Multicenter Airway Research Collaboration prospective cohort study. We excluded infants with direct intensive care unit (ICU) admissions from the index ED visit as they represent a subpopulation for whom there is less clinical conundrum regarding the need for hospitalization. Mild bronchiolitis was defined as: a) sent home after the index ED visit and did not have a return ED visit or had a return ED visit without hospitalization, or b) were hospitalized from the index ED visit to the general inpatient floor with a length of stay (LOS) < 24 hours. Multivariable logistic regression was used to identify factors associated with mild bronchiolitis. Given subjectivity associated with using hospitalization as a marker of severity, we performed a sensitivity analysis excluding infants with an index LOS < 24 hours, as well as those discharged from index ED visit but returned and were hospitalized for < 24 hours.

Results: Of 373 infants aged ≤90 days, 333 were eligible for analysis. Of these, 138 (41%) were aged 61-90 days. One hundred fifty-five (47%) infants had mild bronchiolitis, and none required mechanical ventilation; three infants initially admitted to the general inpatient floor had subsequent care escalated to the ICU (Figure). Demographic factors, illness history, and exam findings are summarized in Table 1. Adjusting for infant characteristics and potential clustering by hospital site, clinical factors associated with mild bronchiolitis included older age (61-90 days versus 0-60 days) (OR 2.72, 95%CI 1.52-4.87), adequate oral intake (OR 4.48, 95%CI 2.08-9.66), and lowest room air oxygen saturation ≥94% (OR 3.12, 95%CI 1.55-6.30) (Table 2). The results of the sensitivity analyses did not differ significantly from the overall study results.

Conclusion(s): Among infants aged ≤90 days presenting to the ED with bronchiolitis, about half had mild bronchiolitis. Mild illness was associated with older age (61-90 days), adequate oral intake, and ≥94% oxygen saturation. These predictors may help in development of clinical strategies to limit unnecessary hospitalization in young infants with bronchiolitis.
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