RESUMO
BACKGROUND: We previously demonstrated that a dose of glucocorticoids (GCs) administered prior to cardiopulmonary bypass (CPB) is effective at suppressing the inflammatory response to CPB and leads to an improved postoperative course. We evaluated whether an additional dose of GC administered eight hours prior to CPB would lead to further clinical benefit. METHODS: We conducted a prospective study in which patients were randomized to receive placebo or GC eight hours prior to CPB, in addition to a dose of GC administered following induction of anesthesia. We measured serum inflammatory mediator levels and postoperative clinical parameters. RESULTS: Thirty-one patients were included in the study. Eighteen patients received two doses of GC and 13 patients received a single does of GC. Complement C3a levels were significantly lower at 24 hours following surgery in those patients who received two doses of GC (3136 ± 1650 vs 1779 ± 1616 ng/mL, P = .04). There was no significant difference in tumor necrosis factor (TNF)-α or interleukin (IL)-6 levels at any time between groups. There was no significant difference in core body temperature or renal function (based on serum creatinine levels) between groups. There was no significant difference between groups in duration of mechanical ventilation (2.4 ± 1.5 vs 3.6 ± 3.7 days, two vs one dose, respectively, P = .33) or length of stay in the intensive care unit ([ICU]; 3.4 ± 1.4 vs 4.9 ± 3.6 days, 2 vs 1 dose, respectively, P = .15). CONCLUSION: While those patients who received two doses of GC prior to surgery had significantly less complement activation postoperatively, clinical outcomes did not differ between groups. We conclude that the practice of administering an additional dose of GC prior to CPB is not supported. However, a large randomized study is needed to conclusively discount the potential benefit of this strategy.
RESUMO
Children undergoing congenital heart surgery are at risk for prolonged mechanical ventilation and length of hospital stay. We investigated the prognostic value of pulmonary dead space fraction as a non-invasive, physiologic marker in this population. In a prospective, cross-sectional study, we measured pulmonary dead space fraction in 52 intubated, pediatric patients within 24 hr postoperative from congenital heart surgery. Measurements were obtained with a bedside, non-invasive cardiac output (NICO) monitor (Respironics Novametrix, Inc., Wallingford, CT). Median pulmonary dead space fraction was 0.46 (25-75% IQR 0.34-0.55). Pulmonary dead space fraction significantly correlated with duration of mechanical ventilation and length of hospital stay in the entire cohort (r(s) = 0.51, P = 0.0002; r(s) = 0.51, P = 0.0002) and in the subset of patients without residual intracardiac shunting (r(s) = 0.45, P = 0.008; r(s) = 0.49, P = 0.004). In a multivariable logistic regression model, pulmonary dead space fraction remained an independent predictor for prolonged mechanical ventilation in the presence of cardiopulmonary bypass time and ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (OR 2.2; 95% CI 1.14-4.38; P = 0.02). The area under the receiver operator characteristic curve for this model was 0.91. Elevated pulmonary dead space fraction is associated with prolonged mechanical ventilation and hospital stay in pediatric patients who undergo surgery for congenital heart disease and has additive predictive value in identifying those at risk for longer duration of mechanical ventilation. Pulmonary dead space may be a useful prognostic tool for clinicians in patients who undergo congenital heart surgery.