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Background Previous latent class analysis of adults with acute respiratory distress syndrome (ARDS) identified two phenotypes, distinguished by the degree of inflammation. We aimed to identify phenotypes in children with ARDS in whom developmental differences might be important, using a latent class analysis approach similar to that used in adults. MethodsThis study was a secondary analysis of data aggregated from the Randomized Evaluation of Sedation Titration for Respiratory Failure (RESTORE) clinical trial and the Genetic Variation and Biomarkers in Children with Acute Lung Injury (BALI) ancillary study. We used latent class analysis, which included demographic, clinical, and plasma biomarker variables, to identify paediatric ARDS (PARDS) phenotypes within a cohort of children included in the RESTORE and BALI studies. The association of phenotypes with clinically relevant outcomes and the performance of paediatric data in adult ARDS classification algorithms were also assessed. Findings 304 children with PARDS were included in this secondary analysis. Using latent class analysis, a two-class model was a better fit for the cohort than a one-class model (p<0•001). Latent class analysis identified two classes: class 1 (181 [60%] of 304 patients with PARDS) and class 2 (123 [40%] of 304 patients with PARDS), referred to as phenotype 1 and 2 hereafter. Phenotype 2 was characterised by higher concentrations of inflammatory biomarkers, a higher incidence of vasopressor use, and more frequent diagnosis of sepsis, consistent with the adult hyperinflammatory phenotype. All levels of severity of PARDS were observed across both phenotypes. Children with the hyperinflammatory phenotype (phenotype 2) had worse clinical outcomes than those with the hypoinflammatory phenotype (phenotype 1), with a longer duration of mechanical ventilation (median 10•0 days [IQR 6•3-21•0] for phenotype 2 vs 6•6 days [4•1-10•8] for phenotype 1, p<0•0001), and higher incidence of mortality (17 [13•8%] of 123 patients vs four [2•2%] of 181 patients, p=0•0001). When using adult phenotype classification algorithms in children, the soluble tumour necrosis factor receptor-1 (sTNFr1), vasopressor use, and interleukin (IL)-6 variables gave an area under the curve (AUC) of 0•956, and the sTNFr1, vasopressor use, and IL-8 variables gave an AUC of 0•954, compared with the gold standard of latent class analysis. Interpretation Latent class analysis identified two phenotypes in children with ARDS with characteristics similar to those in adults, including worse outcomes among patients with the hyperinflammatory phenotype. PARDS phenotypes should be considered in design and analysis of future clinical trials in children.

and the Bright STAR Authorship Group IMPORTANCE Blood culture overuse in the pediatric intensive care unit (PICU) can lead to unnecessary antibiotic use and contribute to antibiotic resistance. Optimizing blood culture practices through diagnostic stewardship may reduce unnecessary blood cultures and antibiotics.OBJECTIVE To evaluate the association of a 14-site multidisciplinary PICU blood culture collaborative with culture rates, antibiotic use, and patient outcomes. DESIGN, SETTING, AND PARTICIPANTS This prospective quality improvement (QI) collaborative involved 14 PICUs across the United States from 2017 to 2020 for the Bright STAR (Testing Stewardship for Antibiotic Reduction) collaborative. Data were collected from each participating PICU and from the Children's Hospital Association Pediatric Health Information System for prespecified primary and secondary outcomes. EXPOSURES A local QI program focusing on blood culture practices in the PICU (facilitated by a larger QI collaborative). MAIN OUTCOMES AND MEASURESThe primary outcome was blood culture rates (per 1000 patient-days/mo). Secondary outcomes included broad-spectrum antibiotic use (total days of therapy and new initiations of broad-spectrum antibiotics Ն3 days after PICU admission) and PICU rates of central line-associated bloodstream infection (CLABSI), Clostridioides difficile infection, mortality, readmission, length of stay, sepsis, and severe sepsis/septic shock.RESULTS Across the 14 PICUs, the blood culture rate was 149.4 per 1000 patient-days/mo preimplementation and 100.5 per 1000 patient-days/mo postimplementation, for a 33% relative reduction (95% CI, 26%-39%). Comparing the periods before and after implementation, the rate of broad-spectrum antibiotic use decreased from 506 days to 440 days per 1000 patient-days/mo, respectively, a 13% relative reduction (95% CI, 7%-19%). The broad-spectrum antibiotic initiation rate decreased from 58.1 to 53.6 initiations/1000 patient-days/mo, an 8% relative reduction (95% CI, 4%-11%). Rates of CLABSI decreased from 1.8 to 1.1 per 1000 central venous line days/mo, a 36% relative reduction (95% CI, 20%-49%). Mortality, length of stay, readmission, sepsis, and severe sepsis/septic shock were similar before and after implementation. CONCLUSIONS AND RELEVANCE Multidisciplinary diagnostic stewardship interventions canreduce blood culture and antibiotic use in the PICU. Future work will determine optimal strategies for wider-scale dissemination of diagnostic stewardship in this setting while monitoring patient safety and balancing measures.

BACKGROUND: Elevated surfactant protein D (SP-D) is a relatively specific indicator of lung injury and is associated with both acute and chronic lung disease in adults and respiratory distress syndrome in premature infants. The relationship between plasma SP-D and lung injury in children with acute respiratory failure is unclear. RESEARCH QUESTION: Is plasma SP-D associated with lung injury or outcome in children with acute respiratory failure? STUDY DESIGN AND METHODS: This was a prospective cohort study in children 2 weeks to 17 years of age with acute respiratory failure who participated in the BALI multi-center study. Analyses were done using SP-D levels in plasma from the first sample taken on either the day of intubation or one of the following 2 days. SP-D level was measured by enzyme-linked immunosorbent assay. RESULTS: Plasma samples from 350 patients were used in the analysis; 233 had pediatric ARDS (PARDS). SP-D levels varied across primary diagnoses (P < .001). Elevated SP-D levels were associated with severe PARDS after adjusting for age, pediatric risk of mortality III (PRISM-III), and primary diagnosis (OR ¼ 1.02; CI ¼ 1.01-1.04; P ¼ .011). Multivariable analyses also indicated that elevated SP-D levels were associated with death (OR ¼ 1.02; CI ¼ 1.01-1.04; P ¼ .004), duration of mechanical ventilation (P ¼ .012), PICU length of stay (P ¼ .019), and highest oxygenation index (P ¼ .040). SP-D levels also correlated with age (r s ¼ 0.16, P ¼ .002). INTERPRETATION: Elevated plasma SP-D levels are associated with severe PARDS and poor outcomes in children with acute respiratory failure. Future studies will determine whether SP-D can be used to predict the degree of lung injury or response to treatment and whether SP-D is useful in identifying PARDS endotypes.