EARLY MARKERS OF MAJOR ADVERSE EVENTS IN CHILDREN AFTER CARDIAC OPERATIONS

Objectives: The purpose of this study was to determine the physiologic variables that predict major adverse events in children in the intens ive care unit after cardiac operations. Methods: A cohort observationa l study was conducted. At the time of admission to the intensive care unit and 4, 8, 12, and 24 hours later the following variables were rec orded: mean arterial pressure, heart rate, cardiac index, oxygen deliv ery, mixed venous oxygen saturation, base deficit, blood lactate, gast ric intramucosal pH, carbon dioxide difference (the difference between arterial carbon dioxide tension and gastric intraluminal carbon dioxi de tension), and toe-core temperature gradient. Major adverse events w ere prospectively identified as cardiac arrest, need for emergency che st opening, development of multiple organ failure, and death. Results: Ninety children were included in the study; 12 had major adverse even ts and there were 4 deaths. Blood lactate level, mean arterial pressur e, and duration of cardiopulmonary bypass were the only significant, i ndependent predictors of major adverse events when measured at the tim e of admission to the intensive care unit. The odds ratio (95% confide nce intervals) for major adverse events if a lactate level was greater than 1.5 mmol/L was 5.1 (1.2 to 22.1), for admission hypotension 2.3 (0.5 to 9.8), and for a cardiopulmonary bypass time greater than 150 m inutes 13.7 (3.3 to 57.2). Four hours after admission lactate and carb on dioxide difference, and 8 hours after admission lactate and base de ficit, were independently significant predictors. The odds ratios for major adverse events if the blood lactate level was greater than 4 mmo l/L at 4 and 8 hours were 8.3 (1.8 to 38.4) and 9.3 (1.9 to 11.3), res pectively. At no time in the first 23 hours were cardiac output, oxyge n delivery, mixed venous oxygen saturation, toe-core temperature gradi ent, or heart rate significant predictors of major adverse events. Con clusions: In the contest of our current treatment strategies, the dura tion of cardiopulmonary bypass and blood lactate level, measured in th e early postoperative period, were the best predictors of impending ma jor adverse events.