title: The impact of phenylephrine, ephedrine, and increased preload on third-generation Vigileo-FloTrac and esophageal doppler cardiac output measurements.
abstract: BACKGROUND
  Cardiac output (CO) monitoring based on pulse contour analysis (Vigileo-FloTrac) has the potential to be used for goal-directed fluid therapy in the perioperative setting. However, factors such as vasopressor usage may impact Vigileo-FloTrac's reliability in tracking CO changes. We tested third-generation Vigileo-FloTrac system's ability to accurately measure the changes in CO induced by vasopressor administration and increased preload in comparison with esophageal Doppler measurements.
  
  
  METHODS
  In 33 anesthetized patients, CO was monitored simultaneously by the third-generation Vigileo-FloTrac and esophageal Doppler. Hemodynamic challenges included phenylephrine (to increase vasomotor tone), ephedrine (to increase myocardial contractility and heart rate), and whole-body tilting (to increase preload). Measurements were performed before and after each intervention.
  
  
  RESULTS
  Overall, 176 pairs of CO measurements were obtained. The difference between paired pulse contour and Doppler measurements of CO was 0.14 ± 2.13 L/min (mean ± SD), and the percentage error (2 SD of the difference divided by the mean CO of the reference method) was 66%. The trending ability of pulse contour versus Doppler was 23% (concordance, the percentage of the total number of data points that are in 1 of the 2 quadrants of agreement) after phenylephrine treatment, 69% (concordance) after ephedrine treatment, and 96% (concordance) after whole-body tilting.
  
  
  CONCLUSIONS
  The pulse contour method of measuring CO, as implemented in the third-generation Vigileo-FloTrac device, accurately tracks changes in CO when preload changes. However, the pulse contour method does not accurately track changes in CO induced with phenylephrine and ephedrine.
authors.affiliation: Department of Anesthesiology and Perioperative Care, University of California, Irvine, Medical Center, 101 City Drive South, Orange, CA 92868, USA.
authors.forename: Lingzhong
authors.initials: L
authors.lastname: Meng
authors.forename: Nam Phuong
authors.initials: NP
authors.lastname: Tran
authors.forename: Brenton S
authors.initials: BS
authors.lastname: Alexander
authors.forename: Kathleen
authors.initials: K
authors.lastname: Laning
authors.forename: Guo
authors.initials: G
authors.lastname: Chen
authors.forename: Zeev N
authors.initials: ZN
authors.lastname: Kain
authors.forename: Maxime
authors.initials: M
authors.lastname: Cannesson
mesh_terms: D000368:Aged; D002140:California; D002302:Cardiac Output / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D015150:Echocardiography, Doppler; D017548:Echocardiography, Transesophageal; D004809:Ephedrine / Q000627:therapeutic use*; D004867:Equipment Design; D005260:Female; D005440:Fluid Therapy; D018475:Head-Down Tilt; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods; D009200:Myocardial Contraction / Q000187:drug effects; D056888:Patient Positioning; D010656:Phenylephrine / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014160:Transducers, Pressure; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000627:therapeutic use*
chemical_list: D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D004809:Ephedrine