Comparison of cardiac output determined by arterial pulse pressure waveform analysis method (FloTrac/Vigileo) versus lithium dilution method in anesthetized dogs


  • The authors declare no conflict of interest.

  • Presented at the 16th International Veterinary Emergency and Critical Care Symposium and Annual Conference of the American College of Veterinary Anesthesiologists, San Antonio, TX, 2010.

Address correspondence and reprint requests to
Dr. Alexander Valverde, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Ontario, Canada N1G 2W1. Email:


Objective – To compare the determination of cardiac output (CO) via arterial pulse pressure waveform analysis (FloTrac/Vigileo) versus lithium dilution method.

Design – Prospective study.

Setting – University teaching hospital.

Animals – Six adult dogs.

Interventions – Dogs were instrumented for CO determinations using lithium dilution (LiDCO) and FloTrac/Vigileo methods. Direct blood pressure, heart rate, arterial blood gases, and end-tidal isoflurane (ETIso) and CO2 concentrations were measured throughout the study while CO was manipulated with different depth of anesthesia and rapid administration of isotonic crystalloids at 60 mL/kg/h.

Measurements and Main Results – Baseline CO measurements were obtained at 1.3% ETIso and were lowered by 3% ETIso. Measurements were obtained in duplicate or triplicate with LiDCO and averaged for comparison with corresponding values measured continuously with the FloTrac/Vigileo method. For 30 comparisons between methods, a mean bias of −100 mL/kg/min and 95% limits of agreement between −311 and +112 mL/kg/min (212 mL/kg/min) was determined. The mean (mL/kg/min) of the differences of LiDCO−Vigileo=62.0402+−0.8383 × Vigileo, and the correlation coefficient (r) between the 2 methods 0.70 for all CO determinations. The repeatability coefficients for the individual LiDCO and FloTrac/Vigileo methods were 187 and 400 mL/kg/min, respectively. Mean LiDCO and FloTrac/Vigileo values from all measurements were 145 ± 68 mL/kg/min (range, 64–354) and 244 ± 144 mL/kg/min (range, 89–624), respectively. The overall mean relative error was 48 ± 14%.

Conclusion – The FloTrac/Vigileo overestimated CO values compared with LiDCO and the relative error was high, which makes this method unreliable for use in dogs.