title: Accuracy of non-invasive measurement of haemoglobin concentration by pulse co-oximetry during steady-state and dynamic conditions in liver surgery.
abstract: BACKGROUND
  The Masimo Radical 7 (Masimo Corp., Irvine, CA, USA) pulse co-oximeter(®) calculates haemoglobin concentration (SpHb) non-invasively using transcutaneous spectrophotometry. We compared SpHb with invasive satellite-lab haemoglobin monitoring (Hb(satlab)) during major hepatic resections both under steady-state conditions and in a dynamic phase with fluid administration of crystalloid and colloid solutions.
  
  
  METHODS
  Thirty patients undergoing major hepatic resection were included and randomized to receive a fluid bolus of 15 ml kg(-1) colloid (n=15) or crystalloid (n=15) solution over 30 min. SpHb was continuously measured on the index finger, and venous blood samples were analysed in both the steady-state phase (from induction until completion of parenchymal transection) and the dynamic phase (during fluid bolus).
  
  
  RESULTS
  Correlation was significant between SpHb and Hb(satlab) (R(2)=0.50, n=543). The modified Bland-Altman analysis for repeated measurements showed a bias (precision) of -0.27 (1.06) and -0.02 (1.07) g dl(-1) for the steady-state and dynamic phases, respectively. SpHb accuracy increased when Hb(satlab) was <10 g dl(-1), with a bias (precision) of 0.41 (0.47) vs -0.26 (1.12) g dl(-1) for values >10 g dl(-1), but accuracy decreased after colloid administration (R(2)=0.25).
  
  
  CONCLUSIONS
  SpHb correlated moderately with Hb(satlab) with a slight underestimation in both phases in patients undergoing major hepatic resection. Accuracy increased for lower Hb(satlab) values but decreased in the presence of colloid solution. Further improvements are necessary to improve device accuracy under these conditions, so that SpHb might become a sensitive screening device for clinically significant anaemia.
authors: Department of Anesthesiology, The University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. j.j.vos@umcg.nl
authors: J J
authors: JJ
authors: Vos
authors: A F
authors: AF
authors: Kalmar
authors: M M R F
authors: MM
authors: Struys
authors: R J
authors: RJ
authors: Porte
authors: J K G
authors: JK
authors: Wietasch
authors: T W L
authors: TW
authors: Scheeren
authors: H G D
authors: HG
authors: Hendriks
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000767:Anesthesia, Epidural; D000768:Anesthesia, General; D001784:Blood Gas Analysis; D003102:Colloids; D000077324:Crystalloid Solutions; D003627:Data Interpretation, Statistical; D005260:Female; D005440:Fluid Therapy; D006454:Hemoglobins / Q000032:analysis*; D006498:Hepatectomy; D006801:Humans; D007552:Isotonic Solutions; D008099:Liver / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D010092:Oximetry / Q000379:methods*; D010952:Plasma Substitutes; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D003102:Colloids; D000077324:Crystalloid Solutions; D006454:Hemoglobins; D007552:Isotonic Solutions; D010952:Plasma Substitutes