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Comparison of Transpulmonary Thermodilution and Calibrated Pulse Contour Analysis with Pulmonary Artery Thermodilution Cardiac Output Measurements in Anesthetized Dogs

Garofalo, N.A., Teixeira‐Neto, F.J., Rodrigues, J.C., Cerejo, S.A., Aguiar, A.J.A., Becerra‐Velásquez, D.R.
Journal of veterinary internal medicine 2016 v.30 no.4 pp. 941-950
anesthesia, cardiac output, dogs, isoflurane, nitroprusside, phenylephrine, pulmonary artery, vasoconstriction, vasodilation
BACKGROUND: Transpulmonary thermodilution (TPTDCO) and calibrated pulse contour analysis (PCACO) are alternatives to pulmonary artery thermodilution cardiac output (PATDCO) measurement. HYPOTHESIS: Ten mL of ice‐cold thermal indicator (TI₁₀) would improve the agreement and trending ability between TPTDCO and PATDCO compared to 5 mL of indicator (TI₅) (Phase‐1). The agreement and TA between PCACO and PATDCO would be poor during changes in systemic vascular resistance (SVR) (Phase‐2). ANIMALS: Eight clinically normal dogs (20.8–31.5 kg). METHODS: Prospective, experimental study. Simultaneous TPTDCO and PATDCO (averaged from 3 repetitions) using TI₅ and TI₁₀ were obtained during isoflurane anesthesia combined or not with remifentanil or dobutamine (Phase‐1). Triplicate PCACO and PATDCO measurements were recorded during phenylephrine‐induced vasoconstriction and nitroprusside‐induced vasodilation (Phase‐2). RESULTS: Mean bias (limits of agreement: LOA) (L/min), percentage bias (PB), and percentage error (PE) were 0.62 (−0.11 to 1.35), 16%, and 19% for TI₅; and 0.33 (−0.25 to 0.91), 9%, and 16% for TI₁₀. Mean bias (LOA), PB, and PE were 0.22 (−0.63 to 1.07), 6%, and 23% during phenylephrine; and 2.12 (0.70–3.55), 43%, and 29% during nitroprusside. Mean angular bias (radial LOA) values were 2° (−10° to 14°) and −1° (−9° to 6°) for TI₅ and TI₁₀, respectively (Phase‐1), and 38° (5°–71°) (Phase‐2). CONCLUSIONS AND CLINICAL IMPORTANCE: Although TI₁₀ slightly improves the agreement and trending ability between TPTDCO and PATDCO in comparison to TI₅, both volumes can be used for TPTDCO in replacement of PATDCO. Vasodilation worsens the agreement between PCACO and PATDCO. Because of PCACO's poor agreement and trending ability with PATDCO during SVR changes, this method has limited clinical application.