Blood Cultures in the Emergency Department Evaluation of Childhood Pneumonia

This study from Philadelphia examined the prevalence of bacteremia in children presenting to the emergency department (ED) with community-acquired pneumonia (CAP), as well as the impact of positive blood cultures on clinical management. A case control study out of The Children's Hospital of Philadelphia (CHOP) Pediatric Research Consortium, it included children from three states including urban, suburban, and semirural locations. Patients were younger than 18 years old, seen in a CHOP ED, and diagnosed with CAP. Exclusion criteria included hospitalization in the last 14 days or presence of an immunocompromising or chronic medical condition predisposing them to severe disease. The included patients were then divided into three groups: those with documented bacteremia (positive blood culture), those without bacteremia (negative or contaminated blood culture), and those without a blood culture. The decision to obtain blood cultures or not was at the discretion of the attending physician, and only blood cultures obtained in the ED were included in the study. During the study, 877 eligible children were seen in the ED with a diagnosis of CAP. Of these, 291 children had blood cultures drawn. The prevalence of bacteremia was 2.1% (95% confidence interval [CI] 0.8–4.4%). Bacteremia was absent in patients discharged home from the ED and patients without an infiltrate on chest radiograph. Bacteremia was more prevalent in subgroups with pneumonia-associated complications (effusion/empyema, lung abscess, necrotizing pneumonia). Among these patients, prevalence of bacteremia was 13% (95% CI 2.8–33.6%). The contamination rate of blood cultures was 1% (95% CI 0.2–3.0%). The results of blood cultures altered management in 5 of 6 cases, resulting in an appropriate broadening (1/5) or an appropriate narrowing (4/5) of coverage. Blood cultures resulted in a change in management in 1 of 3 patients with a contaminated blood culture, resulting in a repeat blood culture and 1 day of unnecessary vancomycin treatment. Interestingly, the authors of this study also report that of the 4 cases of bacteremia caused by Streptococcus pneumoniae, none of the serotypes were included in the heptavalent vaccine used at the time of the study, but 3 of the 4 are included in the 13-valent vaccine used currently. The authors of this study concluded that the overall prevalence of bacteremia in children with CAP is low but tended to be higher in patients with complicated pneumonia. They also concluded that positive blood cultures meaningfully changed clinical management.