Evaluating the Use of Blood Cultures in the Management of Children Hospitalized for Community-Acquired Pneumonia

Abstract

BackgroundBlood cultures are often recommended for the evaluation of community-acquired pneumonia (CAP). However, institutions vary in their use of blood cultures, and blood cultures have unclear utility in CAP management in hospitalized children.ObjectiveTo identify clinical factors associated with obtaining blood cultures in children hospitalized with CAP, and to estimate the association between blood culture obtainment and hospital length of stay (LOS).MethodsWe performed a multicenter retrospective cohort study of children admitted with a diagnosis of CAP to any of four pediatric hospitals in the United States from January 1, 2011-December 31, 2012. Demographics, medical history, diagnostic testing, and clinical outcomes were abstracted via manual chart review. Multivariable logistic regression evaluated patient and clinical factors for associations with obtaining blood cultures. Propensity score-matched Kaplan-Meier analysis compared patients with and without blood cultures for hospital LOS.ResultsSix hundred fourteen charts met inclusion criteria; 390 children had blood cultures obtained. Of children with blood cultures, six (1.5%) were positive for a pathogen and nine (2.3%) grew a contaminant. Factors associated with blood culture obtainment included presenting with symptoms of systemic inflammatory response syndrome (OR 1.78, 95% CI 1.10–2.89), receiving intravenous hydration (OR 3.94, 95% CI 3.22–4.83), receiving antibiotics before admission (OR 1.49, 95% CI 1.17–1.89), hospital admission from the ED (OR 1.65, 95% CI 1.05–2.60), and having health insurance (OR 0.42, 95% CI 0.30–0.60). In propensity score-matched analysis, patients with blood cultures had median 0.8 days longer LOS (2.0 vs 1.2 days, P < .0001) without increased odds of readmission (OR 0.94, 95% CI 0.45–1.97) or death (P = .25).ConclusionsObtaining blood cultures in children hospitalized with CAP rarely identifies a causative pathogen and is associated with increased LOS. Our results highlight the need to refine the role of obtaining blood cultures in children hospitalized with CAP.

Author’s Response

“…1 It is worthwhile to note, possibly because of the multiple simultaneous improvement efforts around the population of patients admitted with acute LRTI, that the length of stay for patients who had a blood culture performed in our study (1.2 days) was lower than that previously reported by Mcculloh et al 6 The standard in our institution is to obtain all blood work, including blood cultures, at the time of intravenous catheter insertion, limiting the vast majority of patients to only a single venipuncture. Although we were unable to determine the number of venipunctures required from the electronic medical record, this concern was never raised during our routine feedback sessions with nursing staff.…”

A Cost-Effectiveness Analysis of Obtaining Blood Cultures in Children Hospitalized for Community-Acquired Pneumonia

“…Once the decision analysis model was created, we surveyed the literature to obtain data on the assumptions needed for the decision tree ( Figure 1 and Table I). Assumptions for this analysis included proportion of patients who will qualify as "high risk" based on published guidelines (32%), 8 proportion of blood cultures that will be positive (3.5%), [5][6][7][8][9][10] proportion of positive blood cultures that will be true positives (60%) vs contaminants (40%) (representing an overall contamination rate of 1.4%), 5-10 and the proportion of true positive cultures, the result of which will lead to a meaningful antibiotic change (meaning the isolated bacteria is not susceptible to ampicillin) (38%). 6 Consistent with a previously published study, for the purpose of this analysis, patients were considered "high risk" if they met any of the following criteria: (1) <6 months with fever or not fully immunized;…”

“…In addition, for this secondary analysis, we assumed a 1.2-day length of stay for children who did not have blood cultures drawn and a 2.0-day length of stay for children who did have a blood culture drawn. 7 Additional Model Assumptions. Several assumptions were made during the construction of this model.…”

“…[4][5][6][7][8] Reported rates of bacteremia in children with CAP range from 1.4%-7.0% in recent studies. [5][6][7][8][9][10] Not surprisingly, hospitals have taken different approaches to this clinical decision.…”

“…[4][5][6][7][8] Reported rates of bacteremia in children with CAP range from 1.4%-7.0% in recent studies. [5][6][7][8][9][10] Not surprisingly, hospitals have taken different approaches to this clinical decision. Published approaches include aiming for obtaining blood cultures in 100% of children admitted with CAP, 9 using criteria to identify children who are at higher risk for bacteremia and obtaining cultures in this subset of patients, 8 and benchmarking performance variation among hospital collaboratives and attempting to associate performance with outcomes.…”