title: Clinical Hemodynamic Parameters Do Not Accurately Reflect Systemic Oxygen Transport in Neonates after the Norwood Procedure.
abstract: OBJECTIVE
  Clinical hemodynamic parameters (heart rate, systolic arterial pressure [SAP], and arterial and venous oxygen saturation saturations [SaO2 and SvO2 ]) are commonly used to guide management to optimize oxygen transport after the Norwood procedure. The adequacy of this practice has not been demonstrated. We examined the correlations between these clinical parameters and direct measurements of oxygen transport in these patients.
  
  
  METHODS
  Oxygen consumption (VO2 ) was measured using respiratory mass spectrometry for 72 hours in 17 neonates after the Norwood procedure. Arterial, superior vena caval, and pulmonary venous blood gases and pressures were measured at intervals of 2-4 hours to calculate cardiac output (CO), systemic and pulmonary blood flows (Qs , Qp), systemic vascular resistance (SVR), total pulmonary vascular resistance including the Blalock-Taussig shunt (tPVR), oxygen delivery (DO2), and extraction ratio (ERO2 ). Heart rate and SAP were also recorded.
  
  
  RESULTS
  Heart rate was positively correlated with VO2 (P = .004) and ERO2 (P = .005). SAP was positively correlated with CO (P = .006), VO2 (P = .02), ERO2 (P = .01), and SVR (P = .08). SaO2 was negatively correlated with tPVR, Qs, and DO2 but positively with Qp and SVR (P < .05 for all). SvO2 was positively correlated with CO, Qs , and DO2 (P < .0001 for all) and negatively correlated with SVR, VO2, and ERO2 (P < .05 for all).
  
  
  CONCLUSIONS
  Routine clinical hemodynamic parameters do not accurately reflect oxygen transport after the Norwood procedure, except for SvO2, which does not differentiate between VO2 and DO2. Higher heart rate and SAP are correlated with a worse balance of oxygen transport. The results of clinical hemodynamic monitoring should be interpreted with caution. Direct measurements of oxygen transport parameters are important in the care of neonates after the Norwood procedure.
authors: Division of Pediatric Cardiology, Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Edmonton, Alberta, Canada.
authors: Santokh
authors: S
authors: Dhillon
authors: Division of Pediatric Cardiology, Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Edmonton, Alberta, Canada.
authors: Xiaoyang
authors: X
authors: Yu
authors: Division of Cardiovascular Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Gencheng
authors: G
authors: Zhang
authors: Congenital Heart Surgeons' Society Data Center, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Sally
authors: S
authors: Cai
authors: Clinical Physiology Research Center, Capital Institute of Pediatrics, Beijing, China.
authors: Jia
authors: J
authors: Li
mesh_terms: D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D058327:Norwood Procedures; D010101:Oxygen Consumption; D011184:Postoperative Period; D011446:Prospective Studies; D015203:Reproducibility of Results
keywords: Clinical Hemodynamic Parameters; Norwood Procedure; Oxygen Transport