Concordância entre o débito cardíaco estimado através das técnicas de termodiluição transpulmonar e de análise de contorno de pulso e a técnica de termodiluição de artéria pulmonar em cães anestesiados com isoflurano
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2016-01-22
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Universidade Estadual Paulista (Unesp)
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Introdução e objetivos: Mensurações do débito cardíaco (DC) pela técnica termodiluição transpulmonar (DCTP) e pela análise de contorno de pulso com calibração pela técnica transpulmonar (DCACP) são alternativas menos invasivas em comparação ao DC fornecido pela técnica de termodiluição de artéria pulmonar (DCP). Entretanto, instabilidades hemodinâmicas podem alterar o desempenho destes métodos. A Fase I do estudo objetivou avaliar se a utilização de 10 mL de indicador térmico (solução fisiológica a ≤ 5oC) para o DCTP (artéria femoral) promoveria melhor concordância e habilidade em detectar alterações no DCP em comparação a 5 mL de indicador. Na Fase II, objetivou-se verificar se alterações na resistência vascular sistêmica (RVS) influenciariam a concordância e a habilidade em detectar tendências entre o DCACP e o DCP. Métodos: Em 8 cães adultos (20,8–31,5 kg), mensurações simultâneas em triplicata do DCTP e DCP foram obtidas utilizando 5 e 10 mL de indicador térmico durante anestesia com isoflurano associado ou não com a infusão contínua intravenosa de remifentanil (0,3 e 0,6 μg/kg/min) ou de dobutamina (2,5 e 5,0 μg/kg/min) (Fase I). Durante a Fase II, o DCACP e o DCP foram mensurados simultaneamente (triplicata) antes e durante alterações na RVS induzidas pela infusão contínua de fenilefrina (1,0 μg/kg/min) ou de nitroprussiato (1,0 μg/kg/min). A acurácia e a precisão da concordância entre métodos foram estudadas pela análise de Bland-Altman para medidas múltiplas (Fase I) e para medidas únicas em um mesmo indivíduo (Fase II). A habilidade dos métodos testados (DCTP e DCACP) em detectar alterações no método de referência (DCP) foi avaliada pela análise gráfica em quatro quadrantes e análise gráfica em coordenadas polares. Resultados: A média das diferenças (limites de concordância, em L/min), “bias” percentual (BP) e erro percentual (EP) entre o DCTP e o DCP foram de 0,62 (-0,11–1,35), 16% (BP) e 19% (EP) com o uso de 5 mL de indicador térmico, e 0,33 (-0,25–0,91), 9% (BP) e 16% (EP) com o emprego de 10 mL de indicador térmico. Durante a Fase II, a média das diferenças (limites de concordância), BP e EP foram de 0,22 (-0,63–1,07), 6% (BP) e 23% (EP) durante a infusão de fenilefrina e de 2,12 (0,70–3,55), 43% (BP) e 29% (EP) durante a administração de nitroprussiato. As taxas de concordância entre o DCTP e DCP foram de 100% para ambos os volumes de sinal térmico após a exclusão de alterações no DC ≤ 0,5 L/min (Fase I). Durante a Fase II, a taxa de concordância entre o DCACP e DCP foi de 63%. O ângulo polar médio e os limites radiais de concordância foram de 2° (-10°–14°) e -1° (-9°–6°) para 5 e 10 mL de indicador térmico, respectivamente (Fase I), e 38° (5°–70°) (Fase II). Conclusões: O DCTP superestima o DCP. O uso de 10 mL de indicador térmico melhora a concordância (acurácia e precisão) e a habilidade em detectar tendências entre o DCTP e o DCP em comparação ao volume de 5 mL. Entretanto, ambos os volumes de indicador térmico podem ser empregados clinicamente para mensuração do DCTP em substituição ao DCP. A vasoconstrição induzida pela fenilefrina não promove deterioração da acurácia da concordância entre o DCACP e o DCP. Entretanto, a vasodilatação induzida pelo nitroprussiato resulta em concordância (acurácia e precisão) clinicamente inaceitável entre o DCACP e o DCP. A DCACP apresenta habilidade pobre em detectar mudanças no DCP durante alterações induzidas na RVS (taxa de concordância < 90%, ângulo polar médio > ± 5º e limites radiais de concordância > ± 30o) e seu emprego não é recomendado clinicamente nestas condições.
Background and objectives: Cardiac output (CO) measurements by transpulmonary thermodilution (TPTDCO) and by pulse contour analysis calibrated with transpulmonary thermodilution (PCACO) are less invasive alternatives to pulmonary artery thermodilution (PATDCO). However, hemodynamic instability could affect the performance of these methods. The objective of Phase I of the study was to determine if the use of 10 mL of thermal indicator (physiological saline at ≤ 5oC) for TPTDCO (measured in the femoral artery) would improve the agreement and trending ability with PATDCO in comparison to 5 mL of indicator. During Phase II, the aim was to verify if changes in systemic vascular resistance (SVR) would alter the agreement and trending ability between PCACO and PATDCO. Methods: In eight adult dogs (20.8–31.5 kg), simultaneous TPTDCO and PATDCO measurements (averaged from 3 repetitions) using 5 and 10 mL of thermal indicator were obtained during isoflurane anesthesia combined or not with intravenous remifentanil (0.3 e 0.6 μg/kg/min) or dobutamine (2.5 e 5.0 μg/kg/min) (Phase-1). During Phase-2, triplicate PCACO and PATDCO measurements were recorded before and during phenylephrine (1.0 μg/kg/min) or nitroprusside (1.0 μg/kg/min) induced changes in SVR. The accuracy and precision of agreement was evaluated by the Bland-Altman method for multiple measurements (Phase I) and for single measurements per subject (Phase 2). The ability of the test methods (PCACO and TPTDCO) to detect changes in the reference method (PATDCO) was evaluated by the four-quadrant plot analysis and by the polar plot analysis. Results: Mean bias, limits of agreement (LOA, in L/min), percentage bias (PB), and percentage error (PE) between TPTDCO and PATDCO were 0.62 (-0.11–1.35), 16% (PB), and 19% (PE) for 5 mL of thermal indicator; and 0.33 (-0.25–0.91), 9% (PB), and 16% (PE) for 10 mL of thermal indicator. During Phase-2, mean bias (LOA), PB, and PE between PCACO and PATDCO were 0.22 (-0.63–1.07), 6% (PB), and 23% (PE) during phenylephrine; and 2.12 (0.70–3.55), 43% (PB), and 29% (PE) during nitroprusside administration. The concordance rates between TPTDCO and PATDCO were 100% for both volumes of thermal signal after excluding CO changes ≤ 0.5 L/min (Phase I). During Phase II the concordance rate between PCACO and PATDCO was 63%. The mean polar angle (radial LOA) values were 2° (-10°–14°) and -1° (-9°–6°) for 5 and 10 mL of thermal indicator, respectively (Phase-1), and 38° (5°–70°) (Phase-2). Conclusions: The TPTDCO method overestimates PATDCO. The use of 10 mL of thermal indicator improves the agreement and trending ability between TPTDCO and PATDCO in comparison to 5 mL. However, both volumes of injectate may be used for measuring TPTDCO interchangeably with PATDCO. Phenylephrine-induced vasoconstriction results in reasonable accuracy of agreement, however nitroprusside-induced vasodilation promotes clinically unacceptable agreement (accuracy and precision) between PCACO and PATDCO. The PCACO shows poor ability to track changes in PATDCO during drug-induced changes in SVR (concordance rate < 90%, mean angular bias > ± 5o, and radial LOA > ± 30o) and is not recommended for clinical use under these conditions.
Background and objectives: Cardiac output (CO) measurements by transpulmonary thermodilution (TPTDCO) and by pulse contour analysis calibrated with transpulmonary thermodilution (PCACO) are less invasive alternatives to pulmonary artery thermodilution (PATDCO). However, hemodynamic instability could affect the performance of these methods. The objective of Phase I of the study was to determine if the use of 10 mL of thermal indicator (physiological saline at ≤ 5oC) for TPTDCO (measured in the femoral artery) would improve the agreement and trending ability with PATDCO in comparison to 5 mL of indicator. During Phase II, the aim was to verify if changes in systemic vascular resistance (SVR) would alter the agreement and trending ability between PCACO and PATDCO. Methods: In eight adult dogs (20.8–31.5 kg), simultaneous TPTDCO and PATDCO measurements (averaged from 3 repetitions) using 5 and 10 mL of thermal indicator were obtained during isoflurane anesthesia combined or not with intravenous remifentanil (0.3 e 0.6 μg/kg/min) or dobutamine (2.5 e 5.0 μg/kg/min) (Phase-1). During Phase-2, triplicate PCACO and PATDCO measurements were recorded before and during phenylephrine (1.0 μg/kg/min) or nitroprusside (1.0 μg/kg/min) induced changes in SVR. The accuracy and precision of agreement was evaluated by the Bland-Altman method for multiple measurements (Phase I) and for single measurements per subject (Phase 2). The ability of the test methods (PCACO and TPTDCO) to detect changes in the reference method (PATDCO) was evaluated by the four-quadrant plot analysis and by the polar plot analysis. Results: Mean bias, limits of agreement (LOA, in L/min), percentage bias (PB), and percentage error (PE) between TPTDCO and PATDCO were 0.62 (-0.11–1.35), 16% (PB), and 19% (PE) for 5 mL of thermal indicator; and 0.33 (-0.25–0.91), 9% (PB), and 16% (PE) for 10 mL of thermal indicator. During Phase-2, mean bias (LOA), PB, and PE between PCACO and PATDCO were 0.22 (-0.63–1.07), 6% (PB), and 23% (PE) during phenylephrine; and 2.12 (0.70–3.55), 43% (PB), and 29% (PE) during nitroprusside administration. The concordance rates between TPTDCO and PATDCO were 100% for both volumes of thermal signal after excluding CO changes ≤ 0.5 L/min (Phase I). During Phase II the concordance rate between PCACO and PATDCO was 63%. The mean polar angle (radial LOA) values were 2° (-10°–14°) and -1° (-9°–6°) for 5 and 10 mL of thermal indicator, respectively (Phase-1), and 38° (5°–70°) (Phase-2). Conclusions: The TPTDCO method overestimates PATDCO. The use of 10 mL of thermal indicator improves the agreement and trending ability between TPTDCO and PATDCO in comparison to 5 mL. However, both volumes of injectate may be used for measuring TPTDCO interchangeably with PATDCO. Phenylephrine-induced vasoconstriction results in reasonable accuracy of agreement, however nitroprusside-induced vasodilation promotes clinically unacceptable agreement (accuracy and precision) between PCACO and PATDCO. The PCACO shows poor ability to track changes in PATDCO during drug-induced changes in SVR (concordance rate < 90%, mean angular bias > ± 5o, and radial LOA > ± 30o) and is not recommended for clinical use under these conditions.
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Palavras-chave
Análise de contorno de pulso, Monitoramento intraoperatório, Débito cardíaco, Termodiluição, Cardiac output, Intraoperative monitoring, Pulse contour analysis, Thermodilution