Bioreactance assessment of cardiac output lacks reliability for the follow-up of patients with pulmonary hypertension.

Cardiac output (CO) is one of the primary prognostic factors evaluated during the follow-up of patients treated for pulmonary hypertension (PH). It is recommended that it be measured using the thermodilution technique during right heart catheterization. The difficulty to perform iterative invasive measurements on the same individual led us to consider a non-invasive option. The aims of the present study were to assess the agreement between CO values obtained using bioreactance (Starling™ SV) and thermodilution, and to evaluate the ability of the bioreactance monitor to detect patients whose CO decreased by more than 15% during follow-up and, accordingly, its usefulness for patient monitoring. A prospective cohort study evaluating the performance of the Starling™ SV monitor was conducted in patients with clinically stable PH. Sixty patients referred for hemodynamic assessment were included. CO was measured using both the thermodilution technique and bioreactance during two follow-up visits. A total of 60 PH patients were included. All datasets were available at the baseline visit (V0) and 50 of them were usable during the follow-up visit (V1). Median [IQR] CO was 4.20 l/min [3.60-4.70] when assessed by bioreactance, and 5.30 l/min [4.57-6.20] by thermodilution (p<0.001). The Spearman correlation coefficient was 0.51 [0.36-0.64], and the average deviation on Bland-Altman plot was -1.25 l/min (95% CI [-1.48-1.01], p<0.001). The ability of the monitor to detect a variation in CO of more than 15% between two follow-up measurements, when such variation existed using thermodilution, was insufficient for clinical practice (AUC = 0.54, 95% CI [0.33-0.75]).

Effect of lower body negative pressure on cardiac and cerebral function in postural orthostatic tachycardia syndrome: A pilot MRI assessment.

Postural orthostatic tachycardia syndrome (POTS) is characterized by an excessive heart rate (HR) response upon standing and symptoms indicative of inadequate cerebral perfusion. We tested the hypothesis that during lower body negative pressure (LBNP), individuals with POTS would have larger decreases in cardiac and cerebrovascular function measured using magnetic resonance (MR) imaging. Eleven patients with POTS and 10 healthy controls were studied at rest and during 20 min of -25 mmHg LBNP. Biventricular volumes, stroke volume (SV), cardiac output (Qc), and HR were determined by cardiac MR. Cerebral oxygen uptake (VO2 ) in the superior sagittal sinus was calculated from cerebral blood flow (CBF; MR phase contrast), venous O2 saturation (SvO2 ; susceptometry-based oximetry), and arterial O2 saturation (pulse oximeter). Regional cerebral perfusion was determined using arterial spin labelling. HR increased in response to LBNP (p < 0.001) with no group differences (HC: +9 ± 8 bpm; POTS: +13 ± 11 bpm; p = 0.35). Biventricular volumes, SV, and Qc decreased during LBNP (p < 0.001). CBF and SvO2 decreased with LBNP (p = 0.01 and 0.03, respectively) but not cerebral VO2 (effect of LBNP: p = 0.28; HC: -0.2 ± 3.7 mL/min; POTS: +1.1 ± 2.0 mL/min; p = 0.33 between groups). Regional cerebral perfusion decreased during LBNP (p < 0.001) but was not different between groups. These data suggest patients with POTS have preserved cardiac and cerebrovascular function.

Assessment of the cardiac output at rest and during exercise stress using real-time cardiovascular magnetic resonance imaging in HFpEF-patients.

This methodological study aimed to validate the cardiac output (CO) measured by exercise-stress real-time phase-contrast cardiovascular magnetic resonance imaging (CMR) in patients with heart failure and preserved ejection fraction (HFpEF). 68 patients with dyspnea on exertion (NYHA ≥ II) and echocardiographic signs of diastolic dysfunction underwent rest and exercise stress right heart catheterization (RHC) and CMR within 24 h. Patients were diagnosed as overt HFpEF (pulmonary capillary wedge pressure (PCWP) ≥ 15mmHg at rest), masked HFpEF (PCWP ≥ 25mmHg during exercise stress but < 15mmHg at rest) and non-cardiac dyspnea. CO was calculated using RHC as the reference standard, and in CMR by the volumetric stroke volume, conventional phase-contrast and rest and stress real-time phase-contrast imaging. At rest, the CMR based CO showed good agreement with RHC with an ICC of 0.772 for conventional phase-contrast, and 0.872 for real-time phase-contrast measurements. During exercise stress, the agreement of real-time CMR and RHC was good with an ICC of 0.805. Real-time measurements underestimated the CO at rest (Bias:0.71 L/min) and during exercise stress (Bias:1.4 L/min). Patients with overt HFpEF had a significantly lower cardiac index compared to patients with masked HFpEF and with non-cardiac dyspnea during exercise stress, but not at rest. Real-time phase-contrast CO can be assessed with good agreement with the invasive reference standard at rest and during exercise stress. While moderate underestimation of the CO needs to be considered with non-invasive testing, the CO using real-time CMR provides useful clinical information and could help to avoid unnecessary invasive procedures in HFpEF patients.

Feasibility of Noninvasive Assessment of Cardiac Output during Exercise in Healthy Adults by a Novel Elaboration on Systolic Time Intervals.

BACKGROUND: Although assessment of cardiovascular hemodynamics during exercise can provide clinical insights, it is challenging to acquire it in clinical settings. OBJECTIVES: Accordingly, this preliminary study was to determine whether a novel elaboration on systolic time interval measures (eSTICO) method of quantifying cardiac output and stroke volume was comparable to those obtained using a validated soluble gas (open circuit CO measure [OpCircCO]) method or calculation based on oxygen consumption (oxygen consumption-based CO [VO2CO]) during exercise. METHODS: For the present study, 14 healthy subjects (male: n = 12, female: n = 2) performed incremental exercise on a recumbent cycle ergometer. At rest and during exercise, cardiac output (CO) was obtained via the eSTICO method, while the OpenCircCO and VO2CO measures were obtained at the last minute of each workload. RESULTS: At peak, there was no difference between eSTICO and OpCircCO (12.39 ± 3.06 vs. 13.96 ± 2.47 L/min, p > 0.05), while there was a slight difference between eSTICO and VO2CO (12.39 ± 3.06 vs. 14.28 ± 2.55 L/min, p < 0.05). When we performed correlation analysis with all subjects and all measures of CO at all WL, between eSTICO and OpenCircCO, there was a good relationship (r = 0.707, p < 0.001) with a Bland and Altman agreement analysis demonstrating a -1.6 difference (95% LoA: -6.3-3.5). Between eSTICO and VO2CO, we observed an r = 0.865 (p < 0.001) and a Bland and Altman agreement analysis with a -1.2 difference (95% LoA: -4.8-2.4). CONCLUSION: A novel exploitation of cardiac hemodynamics using systolic timing intervals may allow a relatively good assessment of CO during exercise in healthy adults.

Preservation of pulsatility with universal ventricular assist device: In vitro assessment for biventricular support.

BACKGROUND: The objective of this study was to assess the pulsatility preservation capability of the universal ventricular assist device (UVAD) when used as a biventricular assist device (BVAD). This evaluation was conducted through an in vitro experiment, utilizing a pulsatile biventricular circulatory mock loop. METHODS: Two UVAD pumps were tested in a dual setup (BVAD) in the circulatory model with the simulated conditions of left heart failure (HF), right HF, and moderate/severe biventricular HF (BHF). The total flow, aortic pulse pressure, the pulse augmentation factor (PAF), the energy-equivalent pressure (EEP), and the surplus hemodynamic energy (SHE) were observed at various pump speeds to evaluate the pulsatility. RESULTS: The aortic pulse pressure increased from the baseline (without pump) in all simulated hemodynamic conditions. The PAF ranged from 17%-35% in healthy, left HF, right HF, and mild BHF conditions, with the highest PAF of 90% being observed in the severe BHF condition. The EEP correlated with LVAD flow in all groups (R2 = 0.87-0.97) and increased from the baseline in all cases. The SHE peaked at approximately 5-6 L/min of LVAD support and was likely to decrease at higher LVAD pump flow. The largest decrease in SHE from the baseline, 53%, was observed in the mild BHF conditions with the highest LVAD and RVAD support. CONCLUSIONS: The UVAD successfully demonstrated the ability to preserve pulsatility in vitro, and to optimize the cardiac output, as an isolated circulatory support device option (RVAD or LVAD) and when used for BVAD support.

Indirect cardiac output assessment in a swine pediatric acute respiratory distress syndrome model.

PURPOSE: To investigate the correlation between volume of carbon dioxide elimination (V̇CO2) and end-tidal carbon dioxide (PETCO2) with cardiac output (CO) in a swine pediatric acute respiratory distress syndrome (ARDS) model. METHODS: Respiratory and hemodynamic variables were collected from twenty-six mechanically ventilated juvenile pigs under general anesthesia before and after inducing ARDS, using oleic acid infusion. RESULTS: Prior to ARDS induction, mean (SD) CO, V̇CO2, PETCO2, and dead space to tidal volume ratio (Vd/Vt) were 4.16 (1.10) L/min, 103.69 (18.06) ml/min, 40.72 (3.88) mmHg and 0.25 (0.09) respectively. Partial correlation coefficients between average CO, V̇CO2, and PETCO2 were 0.44 (95% confidence interval: 0.18-0.69) and 0.50 (0.18-0.74), respectively. After ARDS induction, mean CO, V̇CO2, PETCO2, and Vd/Vt were 3.33 (0.97) L/min, 113.71 (22.97) ml/min, 50.17 (9.73) mmHg and 0.40 (0.08). Partial correlations between CO and V̇CO2 was 0.01 (-0.31 to 0.37) and between CO and PETCO2 was 0.35 (-0.002 to 0.65). CONCLUSION: ARDS may limit the utility of volumetric capnography to monitor CO.

Modified Thermodilution for Simultaneous Cardiac Output and Recirculation Assessment in Veno-venous Extracorporeal Membrane Oxygenation: A Prospective Diagnostic Accuracy Study.

BACKGROUND: Thermodilution is unreliable in veno-venous extracorporeal membrane oxygenation (VV-ECMO). Systemic oxygenation depends on recirculation fractions and ratios of extracorporeal membrane oxygenation (ECMO) flow to cardiac output. In a prospective in vitro simulation, this study assessed the diagnostic accuracy of a modified thermodilution technique for recirculation and cardiac output. The hypothesis was that this method provided clinically acceptable precision and accuracy for cardiac output and recirculation. METHODS: Two ECMO circuits ran in parallel: one representing a VV-ECMO and the second representing native heart, lung, and circulation. Both circuits shared the right atrium. Extra limbs for recirculation and pulmonary shunt were added. This study simulated ECMO flows from 1 to 2.5 l/min and cardiac outputs from 2.5 to 3.5 l/min with recirculation fractions (0 to 80%) and pulmonary shunts. Thermistors in both ECMO limbs and the pulmonary artery measured the temperature changes induced by cold bolus injections into the arterial ECMO limb. Recirculation fractions were calculated from the ratio of the areas under the temperature curve (AUCs) in the ECMO limbs and from partitioning of the bolus volume (flow based). With known partitioning of bolus volumes between ECMO and pulmonary artery, cardiac output was calculated. High-precision ultrasonic flow probes served as reference for Bland-Altman plots and linear mixed-effect models. RESULTS: Accuracy and precision for both the recirculation fraction based on AUC (bias, -5.4%; limits of agreement, -18.6 to 7.9%) and flow based (bias, -5.9%; limits of agreement, -18.8 to 7.0%) are clinically acceptable. Calculated cardiac output for all recirculation fractions was accurate but imprecise (RecirculationAUC: bias 0.56 l/min; limits of agreement, -2.27 to 3.4 l/min; and RecirculationFLOW: bias 0.48 l/min; limits of agreement, -2.22 to 3.19 l/min). Recirculation fraction increased bias and decreased precision. CONCLUSIONS: Adapted thermodilution for VV-ECMO allows simultaneous measurement of recirculation fraction and cardiac output and may help optimize patient management with severe respiratory failure.

Sensores de transductor de gasto cardiaco para pacientes en Unidades Cuidados Intensivos / Cardiac output transducer sensors for patients in intensive care units

ANTECEDENTES: La Unidad Funcional de Evaluación de Tecnologías Sanitarias de INEN se creó el 15 de enero del 2020 mediante R.J. 020-2020-J/INEN y dentro de sus funciones están el "Evaluar aquellas tecnologías sanitarias requeridas por órganos usuarios, que sean nuevas para la entidad y/o no cuenten con cobertura financiera para la/s IAFAS". Definiendo tecnologías sanitarias a "cualquier intervención que pueda ser utilizada en la promoción de la salud, prevención, diagnóstico o tratamiento de una enfermedad, rehabilitación o cuidados prolongados. Se incluyen los medicamentos, los dispositivos, los procedimientos médicos y quirúrgicos, así como los sistemas organizativos dentro de los cuales se proporciona dicha atención sanitaria". INDICACIÓN E INTERVENCIÓN (TECNOLOGÍA SANITARIA) A UTILIZAR: La monitorización hemodinámica es el proceso de medir y evaluar la función cardiovascular, particularmente el gasto cardíaco, la precarga, la poscarga y la contractilidad. El gasto cardíaco es el volumen de sangre que es expulsada por el corazón en un minuto y es un indicador del flujo sanguíneo y la oxigenación de los tejidos. La monitorización hemodinámica se realiza en pacientes críticamente enfermos que tienen alteración del flujo sanguíneo o del equilibrio de líquidos. Existen diferentes métodos de monitorización hemodinámica, clasificados según el grado de invasión y el tipo de tecnología utilizada. Los métodos invasivos implican insertar un catéter en una arteria o vena que está conectado a un transductor que convierte la presión en señales eléctricas. Estas señales se amplifican y se muestran en un monitor donde se pueden consultar valores numéricos y curvas de presión. Los métodos invasivos más populares incluyen: El catéter de arteria pulmonar o Swan-Ganz, que se introduce por una vena central hasta llegar a la arteria pulmonar. Este catéter permite medir la presión venosa central (PVC), la presión arterial pulmonar (PAP), la presión capilar pulmonar (PCP) y el gasto cardíaco por termodilución 4. La termodilución consiste en inyectar un bolo de líquido frío por el catéter y medir los cambios de temperatura en la sangre a través de un termistor. El gasto cardíaco se calcula a partir de la curva de termodilución que se genera. ACERCA DE LA TECNOLOGÍA SANITARIA: El sensor FloTrac™ utiliza la tecnología de análisis de onda de pulso para medir las características de la onda de pulso arterial en el sistema circulatorio del paciente. La información de estas ondas de pulso se procesa y analiza para derivar parámetros hemodinámicos importantes. El sensor se conecta a una línea arterial existente y utiliza un catéter arterial estándar para medir la presión arterial en tiempo real. La información de presión arterial se utiliza para determinar el volumen de sangre que se está bombeando con cada latido cardíaco y, por lo tanto, calcular el gasto cardíaco. El sistema FloTrac™ es utilizado en entornos críticos como unidades de cuidados intensivos (UCI) y salas de operaciones. Permite una monitorización constante y en tiempo real de la función cardíaca y hemodinámica, por lo que podría ser útil para el manejo de pacientes en estado crítico y la toma de decisiones clínicas METODOLOGÍA: Primero se realizó una revisión de los documentos que fueron enviados a la unidad y se conversó con la Unidad de Cuidados Intensivos (Unidad solicitante) del Instituto Nacional de Enfermedades Neoplásicas (INEN). La segunda parte estuvo enfocada en un análisis de la revisión de la literatura para respaldar la decisión basada en evidencia científica. Se seleccionó solo estudios de comparación de diseños metodológicos provenientes de estudios observacionales o experimentales, no se incluyeron reporte de casos; además al ser tecnologías que actualizan sus algoritmos y software de medición, solo se consideró los estudios de los últimos 10 años. Los estudios excluidos se detallan en el Anexo 1. La selección fue realizada solo por un evaluador (VEFR) De un total de 56 estudios, 3 artículos cumplieron con los criterios de selección. A continuación, se muestra el flujo de selección. ANÁLISIS: El estudio de Khwannimit B et al (2020) desarrollado en Tailandia7 , compararon el índice cardíaco (IC) de la medición a través de la onda de presión arterial no calibrado por la cuarta generación de Flotrac y PiCCO comparando con la termodilución transpulmonar en pacientes con shock séptico. Este estudio prospectivo incluyó pacientes con sepsis, que tenían acceso a un catéter venoso central y se excluyeron a quienes tenían derivaciones intracardíacas y arritmias cardíacas (fibrilación auricular o presistoles). A los pacientes se insertó en la arteria femoral dos líneas (PiCCO MP70 y FloTrac 4.0). El nivel de acuerdo y el sesgo entre los métodos se evaluaron mediante análisis de Bland-Altman y se corrigieron con mediciones repetidas. Un total de 31 pacientes fueron evaluados, todos los pacientes recibieron administración de norepinefrina. El promedio de edad fue de 56.3 años, el APACHE II promedio fue de 26.5 ± 8.1 y el SOFA de 9.8 ± 3.7. La gran mayoría de los pacientes tenía una infección del tracto respiratorio 13 pacientes. El estudio de Geisen M et al (2018) realizado en Suiza8 , evaluó la exactitud, precisión de 4 técnicas: PiCCO, LiDCO, FloTrac y Nexfin con el uso de termodilución transpulmonar en pacientes con cirugía de bypass de arteria coronaria electiva para evaluación del gasto cardiaco (GC). Este estudio prospectivo incluyó a 22 pacientes que se encontraban en UCI, se excluyó a pacientes menores de 18 años, gestantes, función de eyección. Se incluyeron 22 pacientes en el estudio y un total de 132 conjuntos de datos coincidentes de 3 ciclos de medición (6 puntos temporales de medición). Se observó una amplia gama de valores de CO durante el período de estudio (3,4-11,6 L/min para ICO, 1,7-10,2 L/min para PCCO, 2,4-11,0 L/min para LCCO, 2,5-9,7 L/min para FCCO y 2,1-10,0 L/min para NCCO). CONCLUSIONES: La monitorización hemodinámica es el proceso de medir y evaluar la función cardiovascular, particularmente el gasto cardíaco, la precarga, la poscarga y la contractilidad. La termodilución consiste en inyectar un bolo de líquido frío por el catéter y medir los cambios de temperatura en la sangre a través de un termistor. El gasto cardíaco se calcula a partir de la curva de termodilución que se genera. Así mismo, existe técnicas mínimamente invasivas, que utilizan técnicas indirectas (como el pulso y presión arteriales) para medir el gasto cardiaco. En este documento se responderá a las solicitudes respecto a: 1) Sensor de transductor de gasto cardíaco. Se realizó una estrategia de búsqueda en PubMed y Cochrane encontrando un total de 135 artículos, donde finalmente se seleccionaron 3 estudios. De los tres estudios, podríamos resumir que el error porcentual de medición de los equipos de medición no invasivos comparados con termodilución transpulmonar fue : Khwannimit en FoTrac (47.4%), Geisen en FloTrac (43.7%) y PiCCO (34.9%); y Lamia en FloTrac (40%) y PiCCO (41%). Concluimos que los estudios no invasivos para estimación de gasto cardiaco tales como FloTrac o PiCCO no podría ser útil en el uso de pacientes con inestabilidad hemodinámica, en comparación con el uso de equipos de termodilución transpulmonar. Concluimos que el costo total anual para realizar la monitorización hemodinámica, mediante ambos procedimientos (con el catéter SwanGanz y con la nueva tecnología), a los pacientes que se encuentran en UCI, corresponde a S/. 44,479,268.21.

Variation in Hemodynamic Assessment and Interpretation: A Call to Standardize the Right Heart Catheterization.

BACKGROUND: Invasive hemodynamic measurement via right heart catheterization has shown divergent data in its role in the treatment of patients with heart failure (HF) and cardiogenic shock. We hypothesized that variation in data acquisition technique and interpretation might contribute to these observations. We sought to assess differences in hemodynamic acquisition and interpretation by operator subspecialty as well as level of experience. METHODS AND RESULTS: Individual-level responses to how physicians both collect and interpret hemodynamic data at the time of right heart catheterization was solicited via a survey distributed to international professional societies in HF and interventional cardiology. Data were stratified both by operator subspecialty (HF specialists or interventional cardiologists [IC]) and operator experience (early career [≤10 years from training] or late career [>10 years from training]) to determine variations in clinical practice. For the sensitivity analysis, we also look at differences in each subgroup. A total of 261 responses were received. There were 141 clinicians (52%) who self-identified as HF specialists, 99 (38%) identified as IC, and 20 (8%) identified as other. There were 142 early career providers (54%) and late career providers (119 [46%]). When recording hemodynamic values, there was considerable variation in practice patterns, regardless of subspecialty or level of experience for the majority of the intracardiac variables. There was no agreement or mild agreement among HF and IC as to when to record right atrial pressures or pulmonary capillary wedge pressures. HF cardiologists were more likely to routinely measure both Fick and thermodilution cardiac output compared with IC (51% vs 29%, P < .001), something mirrored in early career vs later career cardiologists. CONCLUSIONS: Significant variation exists between the acquisition and interpretation of right heart catheterization measurements between HF and IC, as well as those early and late in their careers. With the growth of the heart team approach to management of patients in cardiogenic shock, standardization of both assessment and management practices is needed.

Pulse contour techniques for perioperative hemodynamic monitoring: A nationwide carbon footprint and cost estimation.

BACKGROUND: The question of environmentally sustainable perioperative medicine represents a new challenge in an era of cost constraints and climate crisis. The French Society of Anaesthesia and Intensive Care (SFAR) recommends stroke volume optimization in high-risk surgical patients. Pulse contour techniques have become increasingly popular for stroke volume monitoring during surgery. Some require the use of specific disposable pressure transducers (DPTs), whereas others can be used with standard DPTs. OBJECTIVE: Quantify and compare the carbon footprint and cost of pulse contour techniques using specific and standard DPTs on a yearly basis and at a national level. METHODS: We estimated the number of high-risk surgical patients monitored every year in France with a pulse contour technique, and the plastic waste, carbon footprint and cost associated with the use of specific and standard DPTs. MAIN FINDINGS: When compared to pulse contour techniques working with a standard DPT, techniques requiring a specific DPT are responsible for an increase in carbon dioxide emission estimated at 65-83 tons/yr and for additional hospital cost estimated at €67 million/yr. If, as recommended by the SFAR, all high-risk surgical patients were monitored, the difference would reach 179-227 tons/yr for the environmental impact and €187 million/yr for the economic impact. CONCLUSION: From an environmental and economic standpoint, pulse contour techniques working with standard DPTs should be recommended for the perioperative hemodynamic monitoring of high-risk surgical patients.

Fluid Optimisation in Emergency Laparotomy (FLO-ELA) Trial: study protocol for a multi-centre randomised trial of cardiac output-guided fluid therapy compared to usual care in patients undergoing major emergency gastrointestinal surgery.

INTRODUCTION: Postoperative morbidity and mortality in patients undergoing major emergency gastrointestinal surgery are a major burden on healthcare systems. Optimal management of perioperative intravenous fluids may reduce mortality rates and improve outcomes from surgery. Previous small trials of cardiac-output guided haemodynamic therapy algorithms in patients undergoing gastrointestinal surgery have suggested this intervention results in reduced complications and a modest reduction in mortality. However, this existing evidence is based mainly on elective (planned) surgery, with little evaluation in the emergency setting. There are fundamental clinical and pathophysiological differences between the planned and emergency surgical setting which may influence the effects of this intervention. A large definitive trial in emergency surgery is needed to confirm or refute the potential benefits observed in elective surgery and to inform widespread clinical practice. METHODS: The FLO-ELA trial is a multi-centre, parallel-group, open, randomised controlled trial. 3138 patients aged 50 and over undergoing major emergency gastrointestinal surgery will be randomly allocated in a 1:1 ratio using minimisation to minimally invasive cardiac output monitoring to guide protocolised administration of intra-venous fluid, or usual care without cardiac output monitoring. The trial intervention will be carried out during surgery and for up to 6 h postoperatively. The trial is funded through an efficient design call by the National Institute for Health and Care Research Health Technology Assessment (NIHR HTA) programme and uses existing routinely collected datasets for the majority of data collection. The primary outcome is the number of days alive and out of hospital within 90 days of randomisation. Participants and those delivering the intervention will not be blinded to treatment allocation. Participant recruitment started in September 2017 with a 1-year internal pilot phase and is ongoing at the time of publication. DISCUSSION: This will be the largest contemporary randomised trial examining the effectiveness of perioperative cardiac output-guided haemodynamic therapy in patients undergoing major emergency gastrointestinal surgery. The multi-centre design and broad inclusion criteria support the external validity of the trial. Although the clinical teams delivering the trial interventions will not be blinded, significant trial outcome measures are objective and not subject to detection bias. TRIAL REGISTRATION: ISRCTN 14729158. Registered on 02 May 2017.

Sensor pré-calibrado para monitorização de pressão intravascular e minimamente invasiva do débito cardíaco, Flotrac®, para cirurgias, maiores e de alto risco / Pre-calibrated sensor for intravascular and minimally invasive monitoring of cardiac output, Flotrac®, for major and high-risk surgeries

INTRODUÇÃO: O padrão ouro atual para monitorização hemodinâmica durante cirurgias é o cateter de artéria pulmonar, que exige punção venosa profunda. O FloTrac® é um sistema para monitorização hemodinâmica minimamente invasivo pois conecta-se à uma punção arterial distal, com potencial menor risco de complicações. TECNOLOGIA: Sensor pré-calibrado para monitorização hemodinâmica contínua do débito cardíaco e da pressão intravascular, sistema FloTrac. PERGUNTA: O uso do sistema FloTrac® em pacientes submetidos a procedimentos cirúrgicos de grande porte ou de alto risco é eficaz e seguro quando comparado ao uso do cateter de artéria pulmonar? EVIDÊNCIAS CIENTÍFICAS: As buscas identificaram apenas um ensaio clínico randomizado, cujo objetivo foi comparar o efeito da terapia guiada por metas realizada utilizando o cateter de artéria pulmonar versus o sistema FloTrac® após cirurgia de revascularização miocárdica. Os pacientes do grupo FloTrac® receberam mais volume e ficaram em média cinco horas a menos em suporte ventilatório, ambos desfechos estatisticamente significativos. Estudo com alto risco de viés e certeza da evidência avaliada como muito baixa. AVALIAÇÃO ECONÔMICA (AE): O demandante optou por descartar as diferenças observadas no ensaio clínico e considerar as tecnologias com igual eficácia, adotando um modelo econômico de custo-minimização. O preço do FloTrac® foi ofertado de forma a ser equivalente ao preço do cateter de artéria pulmonar em compras públicas recentes. A busca no Banco de Preços em Saúde foi atualizada pelo parecerista e observou-se que o preço proposto (R$ 1.200,00) está acima do valor SIGTAP (R$ 518,70) e da mediana de preços das compras públicas realizadas nos últimos 18 meses (R$ 358,50 a R$ 380,00 dependendo do tamanho do cateter). ANÁLISE DE IMPACTO ORÇAMENTÁRIO (AIO): A avaliação do impacto orçamentário foi realizada por demanda aferida e considerou apenas o custo de aquisição dos cateteres. O demandante considerou o mesmo preço para as tecnologias e consequentemente impacto orçamentário zero. O impacto foi recalculado com base na mediana e média ponderada dos preços atualizados no BPS em relação ao preço ofertado sendo constatado um impacto incremental em torno de 22,5 a 33,7 milhões de reais em cinco anos. RECOMENDAÇÕES DE AGÊNCIAS DE ATS: CONSIDERAÇÕES FINAIS: A monitorização minimamente invasiva é uma opção à monitorização invasiva com potencial, porém não comprovado, de redução de risco de complicações como infecção associada ao cateter e pneumotórax. Um único ensaio clínico, com muita baixa confiabilidade demonstrou superioridade do FloTrac® em relação ao cateter de artéria pulmonar com redução de cinco horas no tempo médio de ventilação assistida. O demandante optou por considerar eficácia semelhante e ofertar o FloTrac® com preço igual à mediana de preço de compras no BPS do cateter de artéria pulmonar, ou seja, sem custos incrementais ao SUS. Porém, os valores atualizados no BPS são inferiores aos valores apresentados. RECOMENDAÇÃO PRELIMINAR DA CONITEC: Pelo exposto, o Plenário da Conitec, em sua 114ª Reunião Ordinária, no dia 09 de novembro de 2022, deliberou por unanimidade que a matéria fosse disponibilizada em Consulta Pública com recomendação preliminar desfavorável à incorporação do FloTrac®, sistema para monitorização do débito cardíaco minimamente invasivo em cirurgias de grande porte e de alto risco. Os membros da Conitec consideraram que o preço da tecnologia é superior ao preço do cateter de artéria pulmonar hoje disponibilizado no SUS, o que é divergente da proposta apresentada pelo demandante de igualdade de preços e impacto orçamental nulo. Após revisão das compras realizadas nos últimos 18 meses, o preço proposto do FloTrac® (R$ 1.200,00), em relação ao preço do cateter de artéria pulmonar, encontra-se significativamente superior ao valor SIGTAP (R$ 518,70), média ponderada (R$ 380 a R$ 651,34 cateteres 7,0/7,5 french) ou mediana de preços (R$ 358,50 a R$ 380,00 cateteres 7,0/7,5 french) e que por isso causaria um impacto orçamentário incremental sem comprovação de benefícios clínicos ou de segurança que justificassem o investimento. CONSULTA PÚBLICA: Foram recebidas 7 contribuições, sendo todas de experiência e opinião. Diante das argumentações apresentadas, o plenário da Conitec entendeu que não houve argumentação suficiente para mudança de entendimento acerca de sua recomendação preliminar, com base em evidência científica frágil. Desse modo, a Comissão, diante das incertezas quanto ao real benefício do dispositivo, manteve a posição desfavorável à incorporação do sensor pré-calibrado para monitorização hemodinâmica contínua do débito cardíaco e da pressão intravascular, sistema FloTrac. RECOMENDAÇÃO FINAL DA CONITEC: Diante do exposto, os membros presentes do Comitê de Produtos e Procedimentos da Conitec, em sua 116ª Reunião Ordinária, realizada no dia 15 de março de 2023, deliberaram, por unanimidade, recomendar a não incorporação, no SUS, sensor pré-calibrado para monitorização de pressão intravascular e minimamente invasiva do débito cardíaco, FloTrac®, para cirurgias de grande porte e de alto risco. Para essa recomendação, a Conitec considerou que a consulta pública não trouxe elementos novos que alterassem a recomendação preliminar. Foi assinado o registro de deliberação nº 801/2023. DECISÃO: Não incorporar, no âmbito do Sistema Único de Saúde - SUS, o sensor pré-calibrado para monitorização de pressão intravascular e minimamente invasiva do débito cardíaco, FloTrac®, para cirurgias de grande porte e de alto risco, publicada no Diário Oficial da União nº 74, seção 1, página 195, em 18 de abril de 2023.

ARTERIAL DIAMETER VARIATIONS AS A NEW INDEX FOR STROKE VOLUME ASSESSMENT: AN EXPERIMENTAL STUDY ON A CONTROLLED HEMORRHAGIC SHOCK MODEL IN PIGLETS.

ABSTRACT: Background: The assessment of cardiac output (CO) is a major challenge during shock. The criterion standard for CO evaluation is transpulmonary thermodilution, which is an invasive technique. Speckle tracking is an automatized method of analyzing tissue motion using echography. This tool can be used to monitor pulsed arterial diameter variations with low interobserver variability. An experimental model of controlled hemorrhagic shock allows for multiple CO variations. The main aim of this study is to show the correlation between the femoral arterial diameter variations (fADVs) and the stroke volume (SV) measured by thermodilution during hemorrhagic shock management and the resuscitation of anesthetized piglets. The secondary objective is to explore the respective correlations between SV and subaortic time-velocity index, abdominal aorta ADV, carotid ADV, and subclavian ADV. Methods : Piglets were bled until mean arterial pressure reached 40 mm Hg. Controlled hemorrhage was maintained for 30 minutes before randomizing the piglets to three resuscitation groups-the fluid-filling group (reanimated with saline solution only), NEph group (norepinephrine + saline solution), and Eph group (epinephrin + saline solution). Speckle tracking, echocardiographic, and hemodynamic measures were performed at different stages of the protocol. Results : Thirteen piglets were recruited and included for statistical analysis. Of all the piglets, 164 fADV measures were attempted and 160 were successful (98%). The correlation coefficient between fADV and SV was 0.71 (95% confidence interval [CI], 0.62 to 0.78; P < 0.01). The correlation coefficient between SV and abdominal aorta ADV, subclavian ADV, and carotid ADV was 0.30 (95% CI, 0.13 to 0.46; P < 0.01), 0.56 (95% CI, 0.45 to 0.66, P < 0.01), and 0.15 (95% CI, -0.01 to 0.30, P = 0.06), respectively. Conclusions : In this hemorrhagic shock model using piglets, fADV was strongly correlated with SV.

Thermodilution Assessment of Cardiac Index in Patients With Tricuspid Regurgitation.

BACKGROUND: Disparities between thermodilution (TD) and Fick measurements of cardiac index (CI) are common in real-world clinical practice. Published studies about the effect of tricuspid regurgitation (TR) on TD are small and describe conflicting results. We tested the correlation between TD and Fick across a wide range of TR severity, in a larger group of patients undergoing right heart catheterization (RHC). We aimed to determine if TD is an acceptable alternative to Fick in patients with TR in clinical practice. METHODS: We retrospectively evaluated patients undergoing RHC at a single center over a 10-month period, and included those with recent (<90 days) echocardiograms. TD was measured during RHC and Fick was calculated using estimated oxygen consumption. The primary outcome was the correlation between TD and Fick CIs. We performed regression modeling to evaluate predictors of the difference between TD and Fick. RESULTS: A total of 349 patients were included, 40% of whom had at least moderate TR. The correlation between TD and Fick was strong (r=0.765) and did not significantly differ in those with none to mild TR (r=0.73) and those with moderate to severe TR (r=0.80). Atrial fibrillation or atrial flutter was the only variable significantly associated with the difference between CI by Fick and TD (P=.04). CONCLUSION: The correlation between TD and Fick was strong and unaffected by TR severity.

Integral assessment of gas exchange during veno-arterial ECMO: accuracy and precision of a modified Fick principle in a porcine model.

Assessment of native cardiac output during extracorporeal circulation is challenging. We assessed a modified Fick principle under conditions such as dead space and shunt in 13 anesthetized swine undergoing centrally cannulated veno-arterial extracorporeal membrane oxygenation (V-A ECMO, 308 measurement periods) therapy. We assumed that the ratio of carbon dioxide elimination (V̇co2) or oxygen uptake (V̇o2) between the membrane and native lung corresponds to the ratio of respective blood flows. Unequal ventilation/perfusion (V̇/Q̇) ratios were corrected towards unity. Pulmonary blood flow was calculated and compared to an ultrasonic flow probe on the pulmonary artery with a bias of 99 mL/min (limits of agreement -542 to 741 mL/min) with blood content V̇o2 and no-shunt, no-dead space conditions, which showed good trending ability (least significant change from 82 to 129 mL). Shunt conditions led to underestimation of native pulmonary blood flow (bias -395, limits of agreement -1,290 to 500 mL/min). Bias and trending further depended on the gas (O2, CO2) and measurement approach (blood content vs. gas phase). Measurements in the gas phase increased the bias (253 [LoA -1,357 to 1,863 mL/min] for expired V̇o2 bias 482 [LoA -760 to 1,724 mL/min] for expired V̇co2) and could be improved by correction of V̇/Q̇ inequalities. Our results show that common assumptions of the Fick principle in two competing circulations give results with adequate accuracy and may offer a clinically applicable tool. Precision depends on specific conditions. This highlights the complexity of gas exchange in membrane lungs and may further deepen the understanding of V-A ECMO.

Cardiac output assessment methods in left ventricular assist device patients: A problem of heteroscedasticity.

Equipoise remains about how best to measure cardiac output (CO) in patients with left ventricular assist devices (LVAD). In this study, direct Fick CO was compared with thermodilution (TD) and indirect Fick (iFick) CO in 61 LVAD patients. TD and LaFarge iFick showed moderate correlation with direct Fick (R2 = 0.49 and R2 = 0.38, p < 0.001 for both), while Dehmer and Bergstra iFick showed poor correlation with direct Fick (R2 = 0.29 and R2 = 0.31, p < 0.001 for both). Absolute bias between all CO estimation techniques and direct Fick CO was lowest for TD compared to iFick methods but significant for all methods. All methods tended to overestimate CO compared to direct Fick, with greatest overestimation present in those with the lowest measured direct Fick CO. Bias and frequency of significant discrepancy were least using TD and Lafarge iFick CO estimation methods in this study, with TD CO demonstrating modestly better correlation and less heteroscedasticity compared to Lafarge.

Minute Stroke Distance Is a More Reproducible Measurement Than Cardiac Output in the Assessment of Fetal Ventricular Systolic Function.

BACKGROUND: Echocardiographic quantification of fetal cardiac output (CO) aids clinical decision-making in the management of various cardiac and extracardiac diseases. Small variability in measuring semilunar valve dimension significantly reduces the reproducibility of the calculated CO. The authors propose minute stroke distance or velocity-time integral (VTI) as a more reproducible measure reflecting fetal ventricular systolic function. The aim of this study was to test the hypothesis that right and left ventricular minute VTI increase predictably with estimated fetal weight and are more reproducible than CO. METHODS: Five hundred seventy-one singleton fetuses without cardiovascular pathology between 16 and 36 weeks' gestation were reviewed retrospectively. Twenty-two fetuses with pathology resulting in low- or high-CO states were also assessed for comparison. VTI was measured in both ventricular outflow tracts at the level of the semilunar valve, excluding a Doppler insonation angle of >30°. Heart rate, semilunar valve dimension, and VTI determined minute VTI and CO. Inter- and intrarater variability were evaluated in a random 10% subset. RESULTS: Minute VTI and CO measurements were feasible in 67% to 89% of fetuses in this retrospective study. Minute VTI and CO increased with estimated fetal weight nonlinearly (R = 0.61-0.94). The mean inter- and intrarater variability for VTI, 6% and 5.7%, were significantly less than for CO, 25% and 23.7% (P < .001 for all). CONCLUSIONS: Minute VTI is an easily measured, highly reproducible method of quantifying fetal ventricular systolic function. Variability in calculated CO from valve measurement differences is minimized by solely using VTI. Nomograms of minute VTI provide an efficient and precise assessment of fetal systolic function and may be used to track fetuses in disease states with low or high CO.

Fluid responsiveness assessment using inferior vena cava collapsibility among spontaneously breathing patients: Systematic review and meta-analysis.

OBJECTIVE: To synthesize the evidence about diagnostic accuracy of inferior vena cava collapsibility (IVCc) in prediction of fluid responsiveness among spontaneously breathing patients. DESIGN: Systematic review of diagnostic accuracy studies. SETTING: Intensive care units or emergency departments. PATIENTS AND PARTICIPANTS: spontaneously breathing patients with indication for fluid bolus administration. INTERVENTIONS: A search was conducted in MEDLINE and EMBASE. We included studies assessing IVCc accuracy for fluid responsiveness assessment with a standard method for cardiac output measure as index test. MAIN VARIABLES OF INTEREST: General information (year, setting, cutoffs, standard method), sensitivity, specificity, and area under the receiving operator characteristics curve (AUROC). Risk of bias was assessed with QUADAS 2 tool. We obtained the pooled sensitivity, specificity and summary ROC curve, with estimated confidence intervals from a bivariate model. We also calculated positive and negative likelihood ratios and developed a Fagon nomogram. RESULTS: Eight studies were included with 497 patients. Overall, the studies presented a high risk of bias. IVCc sensitivity was 63% (95% CI - 46-78%) and specificity 83% (95% CI - 76-87%). Despite moderate accuracy of IVCc (SROC 0.83, 95% CI - 0.80-0.86), post-test probability of being fluid responsive based on a 50% pre-test probability led to considerable misclassification. CONCLUSIONS: IVCc had moderate accuracy for fluid responsiveness assessment in spontaneously breathing patients and should not be used in isolation for this purpose.