Oxygen saturation is not clinically useful in the exclusion of bacterial pneumonia in febrile infants

Background Acute respiratory infection remains a common presentation to Emergency Departments. Oxygen saturations (Sao 2 ) may be useful in determining which febrile infants require chest x-rays (CXR) in investigation for bacterial pneumonia (PNA). This study aimed to determine whether Sao 2 is clinically useful in excluding bacterial PNA in febrile infants Methods A febrile infant registry was instituted at a tertiary care military hospital (55 000 annual patients, 27% children) from December 2002–December 2003. Eligible patients consisted of infants 2 . Logistic regression for PNA was performed using age, sex, Tmax, RR, HR and Sao 2 . A Receiver Operator Characteristic (ROC) curve was created to show Sao 2 cut-off points as related to sensitivity and specificity. Results 985 patients (55% boys; median age: 12 months) met entry criteria. 790 underwent CXR and 82 were diagnosed with bacterial PNA. Sao 2 was lower in infants with bacterial PNA (96.6%±2.5% vs 97.7%±1.8%, p 2 was also predictive of bacterial PNA by logistic regression (p=0.017) but the ROC curve yielded a poor sensitivity/specificity profile (area under curve (AUC) of 0.6786). Conclusions In febrile infants, Sao 2 was not found to be clinically useful for excluding bacterial PNA.