Plasma levels of alarmin HNPs 1–3 associate with lung dysfunction after cardiac surgery in children

BACKGROUND Early onset of lung injury is considerable common after cardiac surgery and is associated with increasing in morbidity and mortality, but current clinical predictors for the occurrence of this complication always have limited positive warning value. This study aimed to evaluate whether elevated plasma levels of human neutrophil peptides (HNPs) 1-3 herald impaired lung function in infants and young children after cardiac surgery necessitating cardiopulmonary bypass (CPB). METHODS Consecutive children younger than 3 years old who underwent cardiac surgery were prospectively enrolled. Plasma concentrations of HNPs 1-3 and inflammatory cytokines were measured before, and immediately after CPB, as well as at 1 h, 12 h, and 24 h after CPB. RESULTS Thirty patients were enrolled, 18 (60%) of whom were infants. Plasma levels of HNPs 1-3 and the pro-inflammatory cytokine interleukin-6 (IL-6) significantly increased immediately after CPB (P < 0.001), while IL-8 increased 1 h after the CPB operation (P = 0.002). The anti-inflammatory cytokine IL-10 levels were also significantly elevated immediately after CPB compared with the baseline (P < 0.001). The stepwise multiple linear regression analysis showed that the plasma HNPs 1-3 levels immediately after CPB was independent correlated with the declined lung function, as reflected by the PaO2/FiO2 ratio on the first 2 days after operation (for the first day: OR, -1.067, 95% CI, -0.548 to -1.574; P < 0.001; for the second day: OR, -0.667, 95% CI, -0.183 to -1.148; P = 0.009) and prolonged mechanical ventilation time (OR, 0.039, 95% CI, 0.005 to 0.056; P = 0.011). Plasma levels of HNPs 1-3 and IL-10 returned to the baseline values, while IL-6 and IL-8 levels remained significantly higher than baseline 24 h after CPB (P ≤ 0.01). CONCLUSIONS Elevated HNPs 1-3 levels immediately after CPB correlate with impaired lung function, and HNPs 1-3 could serve as a quantifiable early alarmin biomarker for onset of lung injury in infants and young children undergoing cardiac surgery with CPB.