Association between C-reactive protein levels and outcome in acute lung injury in children

Background: Acute lung injury (ALI) is a life threatening condition affecting both children and adults. High plasma C-reactive protein (CRP) levels are associated with favorable outcome in adults with ALI, suggesting a protective physiological effect of high CRP levels. The association between CRP levels and outcome has not been studied in ALI in children. Aim: We hypothesized that increased plasma CRP levels are associated with favorable outcome in ALI in children in terms of 28-day mortality and ventilator free days (VFD). Methods: We performed a historical cohort study in 98 mechanically ventilated children (0-18 years) with ALI. The CRP level within 48 hours of disease onset was tested for association with mortality and VFD. Clinical parameters and ventilator settings were evaluated for possible confounding. Results: Fourteen patients (14%) died within 28 days. The median (Q1;Q3) CRP level in non-survivors was 126 mg/L (64;187) compared to 56 mg/L (20;105) in survivors (p=0.01). For every 10 mg/L rise in CRP level, the unadjusted odds for mortality increased 8.7% (95% CI 2.1%-15.8%). Cardiovascular organ failure (CVOF) at onset of ALI was the strongest predictor for mortality (OR 30.5, 95% CI 6.2-152.5). After adjustment for CVOF, for every 10 mg/L rise in CRP level, the odds for mortality increased 5.0% (95% CI -2.7%-12.6%). Increased CRP levels were associated with a decrease in VFD (ρ -0.26, p=0.01). Conclusion: We conclude that increased plasma CRP levels are not associated with favorable outcome in ALI in children. Based on our findings and existing evidence that pathophysiology in ALI in adults and children differ, we suggest future research should take these differences into consideration.