Validity of respiratory scores in bronchiolitis.

OBJECTIVE: The primary objective of this study was to establish the validity and reliability of 2 respiratory scores, the Respiratory Distress Assessment Instrument (RDAI) and the Children's Hospital of Wisconsin Respiratory Score (CHWRS), in bronchiolitis. A secondary objective was to identify the respiratory score components that most determine overall respiratory status. METHODS: This was a prospective cohort study in infants aged < 1 year seen at Children's Hospital of Wisconsin for bronchiolitis. We evaluated: (1) discriminative validity (the score's ability to discriminate between 2 different outcomes) of the respiratory scores to identify emergency department (ED) disposition by using receiver operating characteristic curves; and (2) construct validity (the score's ability to measure what it is thought to measure, overall respiratory status) by using length of stay (LOS) as a proxy for disease severity and comparing correlations between changes in respiratory scores and LOS. Interrater reliability was established by using intraclass correlation. The contribution of individual respiratory score components to determine ED disposition was studied by using multivariate logistic regression. RESULTS: A total of 195 infants were included. The area under the receiver operating characteristic curve was 0.68 for CHWRS versus 0.51 for RDAI in predicting disposition. There was no correlation between initial respiratory scores or change in respiratory scores over the first 24 hours and LOS. Item analysis revealed that oxygen delivery, subcostal retractions, and respiratory rate were independently correlated with ED disposition. The CHWRS was more reliable than the RDAI. CONCLUSIONS: The CHWRS had modest discriminative validity in predicting ED disposition. Neither the CHWRS nor the RDAI had good construct validity. Respiratory rate, oxygen need, and presence of retractions were most useful in predicting ED disposition.

Factors predicting prolonged hospital stay for infants with bronchiolitis.

BACKGROUND: Prior prediction models for length of stay (LOS) in bronchiolitis have focused more on birth- and disease-related risk factors than on early hospital course factors, particularly common clinical markers including respiratory status and caloric intake. OBJECTIVES: 1) Study the associations of various clinical markers and LOS; and 2) develop a LOS prediction model. DESIGN: Retrospective cohort study. SETTING: Children's Hospital of Wisconsin. PATIENTS: Inclusion criteria were: age < 365 days old; admission between November 1, 2004 and April 15, 2005; final diagnosis of bronchiolitis; placement on the bronchiolitis treatment protocol; and lack of concurrent condition impacting LOS. RESULTS: During the study period, 272/347 infants admitted with bronchiolitis met inclusion criteria. On hospital day 2, infants in the prolonged LOS group (≥ 108 hours) had a significantly greater number of hours on supplemental oxygen, maximum supplemental oxygen use, minimum supplemental oxygen use, maximum respiratory rate, mean respiratory score, and number of times suctioned. They had significantly lower minimum oxygen saturation and caloric intake. Recursive partitioning demonstrated five variables (hours of supplemental oxygen, maximum respiratory rate, minimum supplemental oxygen use, gestation, and caloric intake) to predict short or prolonged LOS with an area under the receiver-operator characteristic curve of 0.89/0.72 in the learning/test trees; sensitivity, 0.85; and specificity, 0.82. CONCLUSIONS: There are important differences between infants with bronchiolitis having short and prolonged hospital stays, including several clinical markers identifiable on hospital day 2. This model may be a useful prediction tool for targeting early interventions for high-risk infants.