INTERLEUKIN-6 LEVELS IN SERUM AND LUNG LAVAGE FLUID OF CHILDREN UNDERGOING OPEN-HEART-SURGERY CORRELATE WITH POSTOPERATIVE MORBIDITY

Objective:To evaluate the relationship of perioperative levels of inte rleukin 6 (IL-6) in serum and bronchoalveolar fluid with morbidity and mortality in children undergoing cardiopulmonary bypass (CPB). Design : Prospective, noninterventional study. Setting: Operating room and pe diatric intensive care unit (PICU) of a university hospital. Intervent ions: None. Measurements and results: IL-6 levels were measured in ser um and lung lavage fluid obtained before, during, and after CPB using the B9.9 bioassay. Alveolar epithelial lilting fluid (AELF) volume was calculated using the urea correction method. Mean intraoperative AELF IL-6 levels increased fourfold compared to preoperative levels, and m ean serum IL-6 levels increased fivefold after CPB. Mean intraoperativ e AELF IL-6 levels correlated with intraoperative blood transfusion (r (2) = 0.18; p = 0.049) and duration of inotropic support (r(2) = 0.29; p = 0.009), mechanical ventilation (r(2) = 0.24; p = 0.019), and PICU stay (r(2) = 0.29; p = 0.008). Mean serum IL-6 levels 2 h after CPB c orrelated with intraoperative blood transfusion (r(2) = 0.3; p = 0.007 ), and with Pediatric Risk of Mortality score on postoperative day 3 ( r(2) = 0.24; p = 0.022), and were higher in patients with massive flui d retention (p = 0.014) and in nonsurvivors (p = 0.003). Conclusions: Serum and alveolar IL-6 levels increase after CPB, and correlate with postoperative morbidity. Serum IL-6 levels also correlate with mortali ty. They may be useful in assessing the severity of the systemic infla mmatory response after CPB.