title: Assessment of the relationship between cerebral and splanchnic oxygen saturations measured by near-infrared spectroscopy and direct measurements of systemic haemodynamic variables and oxygen transport after the Norwood procedure.
abstract: OBJECTIVE
  To evaluate the clinical utility of near-infrared spectroscopic (NIRS) monitoring of cerebral (ScO2) and splanchnic (SsO2) oxygen saturations for estimation of systemic oxygen transport after the Norwood procedure.
  
  
  METHODS
  ScO2 and SsO2 were measured with NIRS cerebral and thoracolumbar probes (in humans). Respiratory mass spectrometry was used to measure systemic oxygen consumption (O2). Arterial (SaO2), superior vena caval (SvO2) and pulmonary venous oxygen saturations were measured at 2 to 4 h intervals to derive pulmonary (Qp) and systemic blood flow (Qs), systemic oxygen delivery (DO2) and oxygen extraction ratio (ERO2). Mixed linear regression was used to test correlations. A study of 7 pigs after cardiopulmonary bypass (study 1) was followed by a study of 11 children after the Norwood procedure (study 2).
  
  
  RESULTS
  Study 1. ScO2 moderately correlated with SvO2, mean arterial pressure, Qs, DO2 and ERO2 (slope 0.30, 0.64. 2.30, 0.017 and -32.5, p < 0.0001) but not with SaO2, arterial oxygen pressure (PaO2), haemoglobin and O2. Study 2. ScO2 correlated well with SvO2, SaO2, PaO2 and mean arterial pressure (slope 0.43, 0.61, 0.99 and 0.52, p < 0.0001) but not with haemoglobin (slope 0.24, p > 0.05). ScO2 correlated weakly with O2 (slope -0.07, p = 0.05) and moderately with Qs, DO2 and ERO2 (slope 3.2, 0.03, -33.2, p < 0.0001). SsO2 showed similar but weaker correlations.
  
  
  CONCLUSIONS
  ScO2 and SsO2 may reflect the influence of haemodynamic variables and oxygen transport after the Norwood procedure. However, the interpretation of NIRS data, in terms of both absolute values and trends, is difficult to rely on clinically.
authors.affiliation: The Cardiac Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: G S
authors.initials: GS
authors.lastname: Van Arsdell
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Cai
authors.forename: T
authors.initials: T
authors.lastname: Humpl
authors.forename: C A
authors.initials: CA
authors.lastname: Caldarone
authors.forename: H
authors.initials: H
authors.lastname: Holtby
authors.forename: A N
authors.initials: AN
authors.lastname: Redington
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D005260:Female; D006330:Heart Defects, Congenital / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D010092:Oximetry; D010100:Oxygen / Q000097:blood* / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010313:Partial Pressure; D011184:Postoperative Period; D019265:Spectroscopy, Near-Infrared; D013154:Spleen / Q000098:blood supply / Q000737:chemistry*; D013552:Swine
chemical_list: D010100:Oxygen