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.

Methods

This 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.

Funding

US National Institutes of Health.

Objective

To compare current analgesia and sedation management practices between critically ill children with pre-existing cognitive impairment and critically ill neurotypical children, including possible indicators of therapeutic efficacy.

Study design

This study used secondary analysis of prospective data from the RESTORE clinical trial, with 2449 children admitted to the pediatric intensive care unit and receiving mechanical ventilation for acute respiratory failure. Subjects with a baseline Pediatric Cerebral Performance Category ≥3 were defined as subjects with cognitive impairment, and differences between groups were explored using regression methods accounting for pediatric intensive care unit as a cluster variable.

Results

This study identified 412 subjects (17%) with cognitive impairment. Compared with neurotypical subjects, subjects with cognitive impairment were older (median, years, 6.2 vs 1.4; P < .001) with more severe pediatric acute respiratory distress syndrome (40% vs 33%; P = .009). They received significantly lower cumulative doses of opioids (median, mg/kg, 14.2 vs 16.2; P < .001) and benzodiazepines (10.6 vs 14.4; P < .001). Three nonverbal subjects with cognitive impairment received no analgesia or sedation. Subjects with cognitive impairment were assessed as having more study days awake and calm and fewer study days with an episode of pain. They were less likely to be assessed as having inadequate pain/sedation management or unplanned endotracheal/invasive tube removal. Subjects with cognitive impairment had more documented iatrogenic withdrawal symptoms than neurotypical subjects.

Conclusions

Subjects with cognitive impairment in this study received less medication, but it is unclear whether they have authentically lower analgesic and/or sedative requirements or are vulnerable to inadequate assessment of discomfort because of the lack of validated assessment tools. We recommend the development of pain and sedation assessment tools specific to this patient population.