title: Comparison of the profiles of postoperative systemic hemodynamics and oxygen transport in neonates after the hybrid or the Norwood procedure: a pilot study.
abstract: 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.
  
  
  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 rate x systolic 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.
authors.affiliation: Division of Cardiology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada, M5G 1X8. jia.li@sickkids.ca
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Gencheng
authors.initials: G
authors.lastname: Zhang
authors.forename: Lee
authors.initials: L
authors.lastname: Benson
authors.forename: Helen
authors.initials: H
authors.lastname: Holtby
authors.forename: Sally
authors.initials: S
authors.lastname: Cai
authors.forename: Tilman
authors.initials: T
authors.lastname: Humpl
authors.forename: Glen S
authors.initials: GS
authors.lastname: Van Arsdell
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Redington
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Caldarone
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D006348:Cardiac Surgical Procedures / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010865:Pilot Projects; D011182:Postoperative Care / Q000379:methods; D011184:Postoperative Period