CUTE LUNG INJURY IS A MAJORcause of acute respiratory failure in patients who are critically ill and is associated with several clinical disorders, including sepsis, pneumonia, and aspiration. 1 Although lifesaving, traditional ventilation strategies with higher tidal volumes and airway pressures can exacerbate lung inflammation and injury. 2 Acute lung injury produces parenchymal lung damage that is heterogeneous and may place the patient at risk for ventilatorassociated lung injury. When patients are supine, the reduced volume of the nondependent-aerated lung is at risk for alveolar overdistention, 3 and the cyclical ventilation of the dependent lung at low volumes can cause recruitmentderecruitment with subsequent mechanical strain. 4 Prone positioning, as For editorial comment see p 248.

Neither individual values nor changes in rSO2 are interchangeable measures of ScvO2 in postoperative pediatric cardiac patients. The unique relationship between changes in PaCO2 and cerebral rSO2 supports the hypothesis that cerebral near-infrared spectroscopy monitors regional cerebral oxygenation. Clinical application of this monitor must include recognition of the clinical variables that affect regional brain oxygenation.

Objectives: The objective of this study was to determine the prevalence of ICU delirium in children less than 18 years old that underwent cardiac surgery within the last 30 days. The secondary aim of the study was to identify risk factors associated with ICU delirium in postoperative pediatric cardiac surgical patients. Design: A 1-day, multicenter point-prevalence study of delirium in pediatric postoperative cardiac surgery patients. Setting: Twenty-seven pediatric cardiac and general critical care units caring for postoperative pediatric cardiac surgery patients in North America. Patients: All children less than 18 years old hospitalized in the cardiac critical care units at 06:00 on a randomly selected, study day. Interventions: Eligible children were screened for delirium using the Cornell Assessment of Pediatric Delirium by the study team in collaboration with the bedside nurse. Measurement and Main Results: Overall, 181 patients were enrolled and 40% (n = 73) screened positive for delirium. There were no statistically significant differences in patient demographic information, severity of defect or surgical procedure, past medical history, or postoperative day between patients screening positive or negative for delirium. Our bivariate analysis found those patients screening positive had a longer duration of mechanical ventilation (12.8 vs 5.1 d; p = 0.02); required more vasoactive support (55% vs 26%; p = 0.0009); and had a higher number of invasive catheters (4 vs 3 catheters; p = 0.001). Delirium-positive patients received more total opioid exposure (1.80 vs 0.36 mg/kg/d of morphine equivalents; p < 0.001), did not have an ambulation or physical therapy schedule (p = 0.02), had not been out of bed in the previous 24 hours (p < 0.0002), and parents were not at the bedside at time of data collection (p = 0.008). In the mixed-effects logistic regression analysis of modifiable risk factors, the following variables were associated with a positive delirium screen: 1) pain score, per point increase (odds ratio, 1.3; 1.06–1.60); 2) total opioid exposure, per mg/kg/d increase (odds ratio, 1.35; 1.06–1.73); 3) SBS less than 0 (odds ratio, 4.01; 1.21–13.27); 4) pain medication or sedative administered in the previous 4 hours (odds ratio, 3.49; 1.32–9.28); 5) no progressive physical therapy or ambulation schedule in their medical record (odds ratio, 4.40; 1.41–13.68); and 6) parents not at bedside at time of data collection (odds ratio, 2.31; 1.01–5.31). Conclusions: We found delirium to be a common problem after cardiac surgery with several important modifiable risk factors.

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.

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.