Accuracy of IL-6 and IL-8 concentrations in exhaled breath condensate in predicting postoperative ARDS in patients undergoing cardiac surgery under cardiopulmonary bypass

Abstract

Objective To evaluate the accuracy of interleukin-6 (IL-6) and IL-8 concentrations in exhaled breath condensate (EBC) in predicting postoperative acute respiratory distress syndrome (ARDS) in the patients undergoing cardiac surgery under cardiopulmonary bypass (CPB). Methods Forty-two American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes, aged 18-64 yr, scheduled for elective cardiac valve replacement under CPB, were selected.EBC samples were collected for determination of the concentrations of IL-6 and IL-8 by enzyme-linked immunosorbent assay.The patients were divided into either ARDS group or non-ARDS group according to whether the patients developed ARDS after surgery.The receiver operating characteristic curve for IL-6 and IL-8 concentrations in EBC in diagnosing postoperative ARDS was plotted, and the area under the curve and 95% confidence interval (CI) were calculated.The critical value, sensitivity and specificity were calculated according to the corresponding concentrations of IL-6 and IL-8 in EBC when Youden index reached the maximal value. Results Twenty-two patients developed postoperative ARDS, and the incidence was 52%.The concentrations of IL-6 and IL-8 in EBC were significantly higher at T2-4 than at T1 in two groups (P<0.05). Compared with group non-ARDS, the concentrations of IL-6 and IL-8 in EBC were significantly increased at T2-4 in group ARDS (P<0.05). The area under the curve (95% CI) of IL-6 concentrations in EBC measured at T2-4 in predicting postoperative ARDS was 0.822 (0.673-0.922), 0.850 (0.706-0.941) and 0.906 (0.775-0.974), respectively, the critical value was 2.92, 5.04 and 2.64 pg/ml, respectively, the sensitivity was 95.5%, 68.2% and 77.3%, respectively, and the specificity was 70.0%, 90.0% and 90.0%, respectively.The area under the curve (95% CI) of IL-8 concentrations in EBC measured at T2-4 in predicting postoperative ARDS was 0.700 (0.539-0.831), 0.851 (0.707-0.942) and 0.737 (0.579-0.861), respectively, the critical value was 26.75, 42.73 and 21.86 pg/ml, respectively, the sensitivity was 68.2%, 77.3% and 72.7%, respectively, and the specificity was 65.0%, 80.0% and 70.0%, respectively. Conclusion The concentrations of IL-6 and IL-8 in EBC can accurately predict the occurrence of postoperative ARDS in the patients undergoing cardiac surgery under CPB. Key words: Interleukins; Respiratory distress syndrome, adult; Cardiopulmonary bypass; Heart valve prosthesis implantation; Exhaled breath condensate