Norwood Procedure-Difficulty in Weaning From Cardiopulmonary Bypass and Implications for Outcomes

Difficulty weaning from cardiopulmonary bypass (CPB) or the need to return to CPB (collectively D-CPB) may occur after the Norwood procedure. We sought to evaluate the relationship between D-CBP and survival. This was a retrospective chart review of all patients undergoing a Norwood procedure at our institution during the interval 2005-2017. Primary outcome was survival for the Norwood procedure. Secondary outcomes included various measures of morbidity. Successful wean from CBP (S-CPB) was defined as no need to return to full-flow CPB during the initial definitive wean or after separation from CPB; otherwise, the classification was difficulty with wean (D-CBP). Successful rescue in the D-CPB group was defined as not requiring extracorporeal life support either in the operating room or within the first 3 postoperative days. Of the 196 patients in the cohort, 49 were D-CPB. Survival for S-CPB was 92.5% (136/147) vs 71.4% (35/49) for D-CPB (P = 0.001). Major morbidity occurred in 29.9% (44/147) in S-CPB vs 69.4% (34/49) in D-CPB (P < 0.001). With multivariable analysis, D-CPB was significantly associated with mortality (odds ratio = 8.09; confidence interval 2.72-24.05; P < 0.001). Successful rescue occurred in 30 of 49 patients in the D-CPB group and demonstrated survival similar to the S-CPB group. In the Norwood patient, D-CPB is an important intraoperative event and prognostic factor for mortality and morbidity. Successful rescue appears to ameliorate the impact of D-CPB on survival.