ABSTRACT
OBJECTIVE: To estimate ratios of pulmonary-to-systemic blood flows (Qp/Qs) after stage I palliation (Norwood operation) for hypoplastic left heart syndrome and to determine whether early postoperative death can be associated with abnormalities of Qp/Qs ratios. DESIGN: Retrospective. SETTING: University hospital. PARTICIPANTS: Patients who underwent stage I palliation (Norwood operation) for hypoplastic left heart syndrome (n = 76). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The results of the last intraoperative blood gas analysis were compared between patients who survived the day of operation (58 of 76) and the patients who died intraoperatively or within 4 hours after operation (18 of 76). Qp/Qs ratios were calculated using the Fick principle from arterial and venous oxygen saturations at estimated pulmonary venous oxygen saturation of 95%. A lower arterial oxygen saturation (SaO(2), 69.0 +/- 20.5% v 77.3 +/- 8.5%; p < 0.05) and more marked metabolic acidosis (pH, 7.244 +/- 0.115 v 7.298 +/- 0.095; p < 0.05; base excess, -6.8 +/- 4.4 v -3.0 +/- 4.2; p < 0.05) were observed in nonsurvivors. Calculated Qp/Qs ratios ranged between 0.2 and 6.5 in survivors and between 0.6 and 1.9 in nonsurvivors. CONCLUSIONS: Postoperative excessive pulmonary blood flow was not implicated as a cause of death based on blood gas data and Qp/Qs ratios. In nonsurvivors, low cardiac output and hypoxemia were assumed to be major problems.
