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Abstract

Introduction: Critically ill children with status asthmaticus frequently present with fever and abnormal chest radiographs. These children are often placed on broad-spectrum antibiotic therapy for clinical suspicion of pneumonia. However, many of these children do not have pneumonia. While previous studies have shown that serum procalcitonin(PCT) levels can predict bacterial infection and decrease antibiotic overuse, there is limited data on PCT levels in children with status asthmaticus. For example, it is not known whether corticosteroids affect PCT levels. The specific aims of this study are to measure PCT levels in critically ill children with status asthmaticus and determine whether increased PCT correlates with presence of co-existing bacterial pneumonia. Methods: With IRB approval, we conducted a 12-month, prospective, cross-sectional study of patients from 1 to 21 years of age who were admitted to the PICU with status asthmaticus. We excluded patients with a known bacterial infection outside the lung, chronic lung disease, cystic fibrosis, bronchiectasis or immunodeficiency. After informed consent, we obtained PCT levels within 8 hours of admission. Patient demographic and clinical data including PRISM scores, radiographic and laboratory results and hospital and ICU length of stay were also collected. A blinded clinician and radiologist reviewed the charts retrospectively for the diagnosis of bacterial pneumonia. Statistical analysis included descriptive statistics, the Mann-Whitney U test, and regression analysis. Results: 61 patients with a median age of 7.3 years (IQR 4, 10) were included in the study. 51% were male. Average PRISM score was 2.7(SD 2.9). 3 patients (5%) were determined to have bacterial pneumonia, whereas 52 (85%) did not. 6 patients (10%) were indeterminate. The mean PCT level for all patients was 0.65ng/ml (SD 1.54). There was no significant difference in the mean PCT levels between the patients with and without bacterial pneumonia (0.33(SD 0.36) vs. 0.69(SD1.67), p=0.44). Regression analysis revealed a significant association with presence of fever with increased PCT level (p=0.004), but no significant correlation between PCT level and presence of pneumonia, length of stay PRISM scores or receipt of antibiotics. Conclusions: Status asthmaticus is not associated with a significant elevation in procalcitonin. Although our study did not find an association with co-existing bacterial pneumonia and PCT elevation, the small sample size may have biased our results - further studies are indicated.