Children undergoing heart transplant are at increased risk for postoperative vasodilatory shock.

Objective: To determine the incidence of vasodilatory shock (VDS) in children after cardiopulmonary bypass (CPB), and to describe this syndrome of post-CPB VDS in children.

Design: Prospective, observational.

Setting: Pediatric and neonatal intensive care units in a tertiary care, children's hospital.

Patients: Three hundred children undergoing CPB.

Intervention: None.

Measurements And Main Results: Three hundred subjects undergoing CPB were evaluated for clinical evidence of VDS following CPB. The incidence of post-CPB VDS was 3%. Characteristics of children who developed VDS: higher peak lactate (6.2 +/- 2.6 vs. 3.0 +/- 2.1 mmol/L; p = 0.0002), higher peak serum blood urea nitrogen (18.5 +/- 4.6 vs. 15.6 +/- 7.2 mg/dL; p = 0.04), lower urine output (1.7 +/- 0.8 vs. 2.6 +/- 0.2 mL/kg/hr; p = 0.04), and fewer intensive care unit free days (14.9 +/- 9.0 vs. 21.1 +/- 7.2 days; p = 0.01). Univariate predictors for the development of post-CPB VDS included children who had heart transplantation (HT) (relative risk [RR], 9.8; 95% confidence interval [CI], 2.7-35.2) or ventricular assist device (VAD) placed (RR, 17.9; 95% CI, 3.8-84.1), a cardiomyopathy diagnosis (RR, 8.5; 95% CI, 2.3-31), age >12 years (RR, 4.5; 95% CI, 1.2-17.0), CPB time >180 minutes (RR, 7.1; 95% CI, 1.9-26.2), and preoperative ventricular dysfunction (RR, 3.7; 95% CI, 1.0-13.4). By stratified analysis, the only independent predictor for the development of VDS was undergoing HT/VAD.

Conclusions: Post-CPB VDS is uncommon in children. However, children who undergo HT or VAD placement are at high risk for developing post-CPB VDS. Recognition that the overall incidence of post-CPB is low-except in the HT/VAD population-may help guide therapy in the pediatric post-CPB patient.