title: Evaluation of the non-calibrated pulse contour cardiac output monitor FloTrac/Vigileo against thermodilution in standing horses.
abstract: OBJECTIVE
  To evaluate the non-calibrated, minimally invasive cardiac output (CO) monitor FloTrac/Vigileo (FloTrac) against thermodilution (TD) CO in standing horses.
  
  
  METHODS
  Prospective, experimental trial.
  
  
  METHODS
  Nine adult horses weighing a median (range) of 535 (470-602) kg.
  
  
  METHODS
  Catheters were placed in the right atrium, pulmonary artery and carotid artery under local anaesthesia. CO was measured 147 times by TD and FloTrac and indexed to body weight. Changes in CO were achieved with romifidine or xylazine and dobutamine constant rate infusions. Bland-Altman analysis, concordance and polar plot analysis were used to assess agreement and ability to track changes in CO.
  
  
  RESULTS
  Mean ± standard deviation COTD of 48 ± 16 mL kg(-1) minute(-1) (range: 19-93 mL kg(-1) minute(-1) ) and mean COF loTrac of 9 ± 3 mL kg(-1) minute(-1) (range: 5-21 mL kg(-1) minute(-1) ) were measured. Low agreement with a large mean bias of 39 mL kg(-1) minute(-1) and wide limits of agreement of 8-70 mL kg(-1) minute(-1) were found. The percentage error of 108% and precision of TD of ± 18% resulted in an estimated precision of FloTrac of ± 106%. Comparison of changes in COF loTrac with changes in COTD gave a concordance rate of 52% in the four-quadrant plot, and a mean polar angle of -11° with radial limits of agreement of ± 61 ° in the polar plot. Mean arterial pressure (MAP) and COF loTrac were positively correlated (r = 0.5, p < 0.0001). No correlation of MAP with COTD was observed.
  
  
  CONCLUSIONS
  The FloTrac system, originally designed for use in humans, neither measured absolute CO in standing horses accurately nor tracked relative changes in CO measured by TD correctly. The false dependence of COF loTrac on arterial blood pressure further discourages the use of this technique in horses.
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Annette P N
authors.initials: AP
authors.lastname: Kutter
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Regula
authors.initials: R
authors.lastname: Bettschart-Wolfensberger
authors.affiliation: Clinic for Equine Internal Medicine, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Colin C
authors.initials: CC
authors.lastname: Schwarzwald
authors.affiliation: Section of Anaesthesiology, VetAgro Sup (Veterinary Campus), University of Lyon, Marcy L'Étoile, France.|INSERM (Institut National de la Santé et de la Recherche Médicale), UMR-1060, CarMeN (Cardiovasculaire, Métabolisme, Diabétologie et Nutrition), Lyon, France.
authors.forename: Karine G
authors.initials: KG
authors.lastname: Portier
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Simone K
authors.initials: SK
authors.lastname: Ringer
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage; D058665:Adrenergic beta-1 Receptor Agonists / Q000008:administration & dosage; D000758:Anesthesia / Q000662:veterinary*; D000777:Anesthetics / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure; D002138:Calibration; D002302:Cardiac Output; D004280:Dobutamine / Q000008:administration & dosage; D005260:Female; D006334:Heart Function Tests / Q000295:instrumentation / Q000662:veterinary*; D006736:Horses; D007093:Imidazoles / Q000008:administration & dosage; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods / Q000662:veterinary*; D013815:Thermodilution; D014991:Xylazine / Q000008:administration & dosage
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D058665:Adrenergic beta-1 Receptor Agonists; D000777:Anesthetics; D007093:Imidazoles; D014991:Xylazine; D004280:Dobutamine; C076257:romifidine
keywords: FloTrac/Vigileo; cardiac output measurement; horses; pulse contour analysis; thermodilution cardiac output