Hemodynamic Characteristics of Neonates Following First Stage Palliation for Hypoplastic Left Heart Syndrome

Abstract

Background It is widely held that the postoperative course of patients with hypoplastic left heart syndrome (HLHS) after stage 1 palliation is characterized by hemodynamic instability, which in part may be due to excessive pulmonary blood flow. Hence, avoidance of alkalosis and the use of minimally oxygen-enriched inspiratory gas are thought by many to be important, although there is little pertinent published data. This study was undertaken to characterize the postoperative course and to determine whether the F io ₂ and blood pH are related to indices of hemodynamic stability in these infants. Methods and Results The postoperative course of 25 consecutive infants undergoing first stage palliation for HLHS were retrospectively reviewed and the following data were obtained: arterial pressure, arterial blood gas measurements, the inotropic agents used, and multiple respiratory parameters. There was one operative death, and 2 patients died within 2 days, but 22 were extubated (mean, 5.2±4.1 days after surgery). Hospital mortality was 24%. Mean pH was ≥7.51 for the first 9 hours after surgery and was ≥7.45 for the entire period. The mean F io ₂ was ≥50% for the first 18 hours. The Pa o ₂ was appropriate (37±6 mm Hg at 1 hour after surgery, increasing to 45±5 mm Hg by hour 73). Only modest inotropic support was needed to maintain appropriate blood pressure. Conclusions These data suggest that neither alkalosis nor relatively high inspired oxygen necessarily cause hemodynamic instability in these patients. To what extent these results are generalizable is unclear, but they suggest that there is nothing inherent with HLHS that mandates postoperative hemodynamic instability or unacceptable mortality.