title: Tissue hemoglobin monitoring is unable to follow variations of arterial hemoglobin during transitions from pulsatile to constant flow in cardiac surgery.
abstract: OBJECTIVE
  To test whether the variations of tissue hemoglobin concentration (∆THb) measured by the FORE-SIGHT(TM) cerebral oximeter can accurately detect changes in arterial hemoglobin concentration (∆AHb) before, during, and after cardiopulmonary bypass.
  
  
  METHODS
  A prospective clinical study.
  
  
  METHODS
  Cardiac surgery operating room.
  
  
  METHODS
  Thirty patients scheduled for cardiac surgery.
  
  
  METHODS
  Tissue hemoglobin concentration (THb) was recorded continuously via 2 sensors applied on the forehead and connected to the cerebral oximeter. Arterial hemoglobin concentration (AHb) was measured in a hematology analyzer laboratory. Hemodynamic and respiratory parameters as well as epidemiologic data also were noted. Data were collected at 3 perioperative times: After induction of anesthesia, 10 minutes after cardioplegia, and at the end of the surgery.
  
  
  RESULTS
  Ninety pairs of data were collected. The coefficient of linear regression between ∆THb and ∆AHb was 0.4 (p<0.001). After exclusion of Hb variations<5%, the trending ability of THb to predict ∆AHb was 87%. However, the Bland and Altman plot graph for THb and AHb showed major limits of agreement (2.4 times the standard deviation). Central venous pressure and carbon dioxide tension were linked independently and positively with THb (p = 0.03).
  
  
  CONCLUSIONS
  Continuous monitoring of THb cannot accurately track variations of AHb during the transition from pulsatile to continuous flow and vice versa in cardiac surgery. Local hemodynamic factors such as PaCO2 and vasodilation significantly impact THb. In this setting, THb monitoring should not be used to guide eventual blood transfusion management.
authors: Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France; Laboratory EA4169, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France. Electronic address: oldesebbe@yahoo.com.
authors: Olivier
authors: O
authors: Desebbe
authors: Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Cecile
authors: C
authors: Faulcon
authors: Department of Anesthesiology and Perioperative Care, University of California, Irvine, CA.
authors: Roland
authors: R
authors: Henaine
authors: Department of Surgery, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Levina
authors: L
authors: Tran
authors: Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Catherine
authors: C
authors: Koffel
authors: Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Bertrand
authors: B
authors: Delannoy
authors: Department of Anesthesiology and Intensive Care, Wertheimer Pierre Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Jean-Jacques
authors: JJ
authors: Lehot
authors: Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France; Laboratory EA4169, Louis Pradel Hospital, Claude Bernard Lyon 1 University, Lyon, France.
authors: Olivier
authors: O
authors: Bastien
authors: Hospices Civils de Lyon, Université Lyon I, Villeurbanne, and Service de Biostatistique, UMR 5558, Laboratoire Biostatistique Santé, Pierre-Bénite, France.
authors: Delphine
authors: D
authors: Maucort-Boulch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002496:Central Venous Pressure; D005260:Female; D006452:Hemoglobinometry / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010092:Oximetry / Q000379:methods*; D011184:Postoperative Period; D011446:Prospective Studies
chemical_list: D006454:Hemoglobins; D002245:Carbon Dioxide
keywords: cardiac surgery; hemoglobin; intraoperative; monitoring; near-infrared spectroscopy; tissue hemoglobin concentration