Capillary Blood Gas Predicts Risk of Intensive Care in Children with Bronchiolitis.

Background: Bronchiolitis may result in respiratory failure diagnosed with arterial blood gas (ABG). ABG is not routinely performed in general paediatric wards but is closely reflected by capillary blood gas (CBG). We sought to assess the usefulness of CBG results in prediction of intensive care unit (ICU) transfer, antibiotic treatment, and length of stay in children hospitalized due to bronchiolitis.

Methods: The optimal cutoff values were estimated with an ROC analysis, while a multiple regression model calculated the odds of an ICU transfer, prolonged hospitalization, and antibiotic treatment related with hypercapnia (pCO ≥ 45 mmHg) and acidosis (pH ≤ 7.35). The correlation between the CBG (pH, pCO, and SatO) and the clinical/laboratory parameters (breath rate, heart rate, pulse oximetry, white blood cells, CRP, and procalcitonin) was calculated.

Results: The CBG was performed in 485 children aged 8 days-22 months (median 2 months). The pCO was significantly higher in ICU transferred patients (median 44.8 mmHg vs. 36.2 mmHg, < 0.01), and showed AUC = 0.773, (95% CI: 0.638-0.907, < 0.01) for ICU transfer (67% sensitivity, 82% specificity, 10.8% positive and 98.7% negative predictive value at cutoff 41.8 mmHg). Hypercapnia (OR = 6.63, 95% CI: 2.15-20.46, < 0.01) and acidosis (OR = 5.01, 95% CI: 1.26-19.9, = 0.022) predicted the ICU transfer independently. The CBG parameters were not related to prolonged hospitalization or antibiotic treatment, and showed only a weak and clinically irrelevant correlation with other laboratory and clinical parameters.

Conclusions: Acidosis and hypercapnia indicate patients at risk of an ICU transfer, and the pCO levels (including values lower than hypercapnia) seem to be a promising marker in ICU risk assessment.