A Targeted Analysis of Serial Cytokine Measures and Nonpulmonary Organ System Failure in Children With Acute Respiratory Failure: Individual Measures and Trajectories Over Time.

OBJECTIVES: There is a need for research exploring the temporal trends of nonpulmonary organ dysfunction (NPOD) and biomarkers in order to identify unique predictive or prognostic phenotypes. We examined the associations between the number and trajectories of NPODs and plasma biomarkers of early and late inflammatory cascade activation, specifically plasma interleukin-1 receptor antagonist (IL-1ra) and interleukin-8 (IL-8), respectively, in the setting of acute respiratory failure (ARF). DESIGN: Secondary analysis of the Randomized Evaluation for Sedation Titration for Respiratory Failure clinical trial and Biomarkers in Acute Lung Injury (BALI) ancillary study. SETTING: Multicenter. PATIENTS: Intubated pediatric patients with ARF. INTERVENTIONS: NPODs were evaluated against plasma IL-1ra and IL-8 levels on individual days (1 to 4 d after intubation) and longitudinally across days. MEASUREMENTS AND MAIN RESULTS: Within the BALI cohort, 432 patients had at least one value for IL-1ra or IL-8 within days 0 through 5. 36.6% had a primary diagnosis of pneumonia, 18.5% had a primary diagnosis of sepsis and 8.1% died. Multivariable logistic regression models showed that increasing levels of both plasma IL-1ra and IL-8 were statistically significantly associated with increasing numbers of NPODs (IL-1ra: days 1-3; IL-8: days 1-4), independent of sepsis diagnosis, severity of oxygenation defect, age, and race/ethnicity. Longitudinal trajectory analysis identified four distinct NPOD trajectories and seven distinct plasma IL-1ra and IL-8 trajectories. Multivariable ordinal logistic regression revealed that specific IL-1ra and IL-8 trajectory groups were associated with greater NPOD trajectory group ( p = 0.004 and p < 0.0001, respectively), independent of severity of oxygenation defect, age, sepsis diagnosis, and race/ethnicity. CONCLUSIONS: Both the inflammatory biomarkers and number of NPODs exhibit distinct trajectories over time with strong associations with one another. These biomarkers and their trajectory patterns may be useful in evaluating the severity of multiple organ dysfunction syndrome in critically ill children and identifying those phenotypes with time-sensitive, treatable traits.