title: Cardiac output derived from arterial pressure waveform analysis in patients undergoing liver transplantation: validity of a third-generation device.
abstract: BACKGROUND
  Hemodynamic monitoring is essential to a successful liver transplantation procedure. FloTrac, a hemodynamic monitor that uses arterial-waveform-based pulse contour analysis for cardiac output (CO) measurement, has proven useful in many clinical settings. One of the primary foci of FloTrac's recent third-generation software upgrade was improving its accuracy in low systemic vascular resistance status. We evaluated the accuracy of the upgraded FloTrac monitor during liver transplantation.
  
  
  METHODS
  Twenty-eight patients undergoing liver transplantation were enrolled in the study. Two sets of CO were measured with a radial arterial line connected to a FloTrac monitor (COFT) and a pulmonary artery catheter connected to a continuous cardiac output Vigilence monitor (COPAC). Simultaneous CO measurement was performed and recorded every 5 minutes throughout the surgery. Bland-Altman analysis was used to estimate the accuracy. The comparative method and reference method were considered interchangeable if the limits of agreement did not exceed a threshold set a priori at the greater of ±1 L/min, or a percentage error of lesser than 30%.
  
  
  RESULTS
  In all, 3234 paired data were collected. The bias was -0.8 L/min and the limits of agreements were -5.6 to 4.0 L/min. Percentage error was 75%. Regression analysis of the systemic vascular resistance index (SVRI) and the bias between COPAC and COFT showed that the bias was inversely related to the SVRI [r2=0.49; P<.001, y=-32.1983+9.9978 Log(x)].
  
  
  CONCLUSIONS
  Despite a software upgrade, the effectiveness of the FloTrac artery-derived cardiac output monitor for CO measurement during liver transplantation remains limited.
authors.affiliation: Department of Anesthesia, Chang Gung Memorial Hospital-Linkou, and College of Medicine, Chang Gung University, Kwei-Shan Taoyuan, Taiwan.
authors.forename: B C
authors.initials: BC
authors.lastname: Su
authors.forename: Y F
authors.initials: YF
authors.lastname: Tsai
authors.forename: C Y
authors.initials: CY
authors.lastname: Chen
authors.forename: H P
authors.initials: HP
authors.lastname: Yu
authors.forename: M W
authors.initials: MW
authors.lastname: Yang
authors.forename: W C
authors.initials: WC
authors.lastname: Lee
authors.forename: C C
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D001794:Blood Pressure; D015924:Blood Pressure Monitors; D002302:Cardiac Output; D002407:Catheterization, Swan-Ganz; D004867:Equipment Design; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000503:physiopathology / Q000601:surgery*; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D011237:Predictive Value of Tests; D017534:Radial Artery; D012044:Regression Analysis; D015203:Reproducibility of Results; D012984:Software; D013624:Taiwan; D013997:Time Factors; D014655:Vascular Resistance