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(Circulation. 2007;116:I-179 – I-187.)
© 2007 American Heart Association, Inc.

Surgery for Congenital Heart Disease

Comparison of the Profiles of Postoperative Systemic Hemodynamics and Oxygen Transport in Neonates After the Hybrid or the Norwood Procedure

A Pilot Study

Jia Li, MD, PhD; Gencheng Zhang, MD, PhD; Lee Benson, MD; Helen Holtby, MBBS; Sally Cai, MS; Tilman Humpl, MD; Glen S. Van Arsdell, MD; Andrew N. Redington, MD; Christopher A. Caldarone, MD

From the Heart Center, the Hospital for Sick Children, Toronto, Ontario, Canada.

Correspondence to Jia Li, Division of Cardiology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada, M5G 1X8. E-mail jia.li{at}sickkids.ca

Background— After the Norwood procedure, early postoperative neonatal physiology is characterized by hemodynamic instability and imbalance of oxygen transport that is commonly attributed to surgical myocardial injury and a systemic inflammatory response to cardiopulmonary bypass (CPB). Because the Hybrid procedure (arterial duct stenting and bilateral pulmonary artery banding) avoids CPB, cardioplegic arrest, and circulatory arrest, we hypothesized that the Hybrid procedure is associated with superior postoperative hemodynamics and oxygen transport.

Methods and Results— Oxygen consumption (VO₂) was continuously measured using respiratory mass spectrometry for 72 hours after Hybrid (n=6) and Norwood (n=13) procedures. Arterial, superior vena cava, and pulmonary venous blood gases and pressures were measured at 2- to 4-hour intervals to calculate systemic and pulmonary blood flows (Qs, Qp), and systemic vascular resistance (SVR), total pulmonary vascular resistance including pulmonary arterial band or B-T shunt (tPVR), cardiac output (CO), oxygen delivery (DO₂), and oxygen extraction ratio (ERO₂). Rate-pressure product was calculated as heart ratexsystolic arterial pressure. When compared with the Norwood procedure, the early postoperative Hybrid patients had lower CO, higher SVR, and higher Qp:Qs ratios. In addition, the DO₂ and VO₂ were both lower in the Hybrids with higher ERO₂ and lactate levels. This early postoperative pattern reversed after 48 hours.

Conclusions— Although Hybrid procedure avoids CPB and cardioplegic arrest, the early hemodynamic profile is not superior to the Norwood in terms of cardiac output and control of pulmonary blood flow. These data strongly suggest that a "hands off" approach to postoperative care in Hybrid patients may not be appropriate in patients with preoperative diminished myocardial function; and in such patients a Norwood-derived management strategy (afterload reduction and inotropic support) should be considered.

Key Words: cardiac output • cardiopulmonary bypass • heart defects, congential • hemodynamics • oxygen