New studies raise doubts on the reliability of physical exam findings in suspected pediatric community-acquired pneumonia cases and on the value of blood cultures in hospitalized pediatric CAP cases.
In one study, 128 cases of suspected CAP in children aged 3 months to 18 years presenting to an ED from July 2013 to May 2016 underwent paired assessments within 20 minutes of each other. Only 3 of 19 exam findings used to diagnose CAP – wheezing, retractions, and respiratory rate – had acceptable levels of inter-rater reliability, with the lower end of the 95% confidential interval at a Fleiss’ kappa value of 0.4 or higher.
Eight exam findings – capillary refill time, cough, rhonchi, head bobbing, behavior, grunting, general appearance, and decreased breath sounds – had poor to fair reliability, with a kappa of 0-0.4, the investigators found. These results came from an ongoing prospective cohort study of children with suspected CAP called Catalyzing Ambulatory Research in Pneumonia Etiology and Diagnostic Innovations in Emergency Medicine, or CARPE DIEM.
“The reliability of these findings must be considered in the clinical management and research of children with CAP,” said lead author Todd Florin, MD, associate research director in emergency medicine at Cincinnati Children’s Hospital Medical Center and his associates. (Pediatrics. 2017;140:e20170310)
In a retrospective cohort analysis, researchers found that just 2.5% of 2,568 hospitalized children with CAP who had a blood culture performed actually grew a pathogen. And of the detected pathogens, 82% were susceptible to penicillin. Streptococcus pneumoniae accounted for 78% of all the pathogens that were found; it was detected in only 2% of all children who had blood cultures taken.
Just 11 children – or 0.43% of the children with a blood culture performed – had growth of a pathogen that was not treatable with penicillin, said lead author Mark Neuman, MD, director of research at Boston Children’s Hospital and his associates (Pediatrics. 2017;140:e20171013).
The analysis was drawn from a cohort of 7,509 children hospitalized from 2007 to 2011, with children with complex chronic conditions excluded. Data for the analysis came from the Pediatric Health Information System Plus database, in which administrative, billing, laboratory, and radiographic information is stored from six tertiary children’s hospitals.
The investigators said that one challenge is that when blood cultures are drawn early in the course of evaluation and treatment, the severity of the child’s CAP might not be apparent, which makes it difficult to know which children would benefit from a blood culture.
“The routine performance of blood cultures in these children may not be indicated,” Dr. Neuman and his associates said. “Researchers in future studies should seek to identify the clinical characteristics of children in whom obtaining blood cultures would lead to changes in clinical management, especially when identifying those patients at risk for CAP caused by organisms not susceptible to guideline-recommended, narrow-spectrum antibiotics.”
Both studies were funded by the National Institutes of Health. For the physician exam study, additional funding was provided by individual grants from the Gerber Foundation, the National Center for Research Resources and the National Center for Advancing Translational Sciences, the National Institute for Allergy and Infectious Diseases and the National Institutes of Health, and a Trustee Award from Cincinnati Children’s Hospital Medical Center. For the blood cultures study, individual researchers received funding from the National Institute of Allergy and Infectious Diseases and the Agency for Healthcare Research and Quality. For the physician exam study, no financial disclosures were reported. For the blood cultures study, Anne Blaschke, MD, PhD, reported receiving research funding from and other financial relationships with BioFire Diagnostics.