Anesthesiology. 2020 Oct 1;133(4):879-891. doi: 10.1097/ALN.0000000000003443.
Veno-arterial extracorporeal membrane oxygenation therapy is a growing treatment modality for acute cardiorespiratory failure. Cardiac output monitoring during veno-arterial extracorporeal membrane oxygenation therapy remains challenging. This study aims to validate a new thermodilution technique during veno-arterial extracorporeal membrane oxygenation therapy using a pig model.
Sixteen healthy pigs were centrally cannulated for veno-arterial extracorporeal membrane oxygenation, and precision flow probes for blood flow assessment were placed on the pulmonary artery. After chest closure, cold boluses of 0.9% saline solution were injected into the extracorporeal membrane oxygenation circuit, right atrium, and right ventricle at different extracorporeal membrane oxygenation flows (4, 3, 2, 1 l/min). Rapid response thermistors in the extracorporeal membrane oxygenation circuit and pulmonary artery recorded the temperature change. After calculating catheter constants, the distributions of injection volumes passing each circuit were assessed and enabled calculation of pulmonary blood flow. Analysis of the exponential temperature decay allowed assessment of right ventricular function.
Calculated blood flow correlated well with measured blood flow (r2 = 0.74, P < 0.001). Bias was -6 ml/min [95% CI ± 48 ml/min] with clinically acceptable limits of agreement (668 ml/min [95% CI ± 166 ml/min]). Percentage error varied with extracorporeal membrane oxygenation blood flow reductions, yielding an overall percentage error of 32.1% and a percentage error of 24.3% at low extracorporeal membrane oxygenation blood flows. Right ventricular ejection fraction was 17 [14 to 20.0]%. Extracorporeal membrane oxygenation flow reductions increased end-diastolic and end-systolic volumes with reductions in pulmonary vascular resistance. Central venous pressure and right ventricular ejection fractions remained unchanged. End-diastolic and end-systolic volumes correlated highly (r2 = 0.98, P < 0.001).
Adapted thermodilution allows reliable assessment of cardiac output and right ventricular behavior. During veno-arterial extracorporeal membrane oxygenation weaning, the right ventricle dilates even with stable function, possibly because of increased venous return.
静脉-动脉体外膜肺氧合治疗是急性心肺衰竭的一种日益增长的治疗方式。静脉-动脉体外膜肺氧合治疗期间的心输出量监测仍然具有挑战性。本研究旨在使用猪模型验证一种新的热稀释技术在静脉-动脉体外膜肺氧合治疗中的应用。
16 头健康猪接受中心置管进行静脉-动脉体外膜肺氧合治疗，并在肺动脉上放置精密血流探头进行血流评估。胸部闭合后，以不同的体外膜肺氧合流量（4、3、2、1 l/min）将 0.9%生理盐水冷弹丸注入体外膜肺氧合回路、右心房和右心室。体外膜肺氧合回路和肺动脉中的快速响应热敏电阻记录温度变化。计算导管常数后，评估通过每个回路的注射体积分布，并能够计算肺血流量。指数温度衰减分析可评估右心室功能。
计算出的血流量与测量的血流量相关性良好（r2 = 0.74，P < 0.001）。偏差为-6 ml/min[95%置信区间±48 ml/min]，具有可接受的一致性界限（668 ml/min[95%置信区间±166 ml/min]）。百分比误差随体外膜肺氧合血流减少而变化，总百分比误差为 32.1%，低体外膜肺氧合血流时百分比误差为 24.3%。右心室射血分数为 17[14 至 20.0]%。随着肺血管阻力的降低，体外膜肺氧合血流减少增加了舒张末期和收缩末期容积。中心静脉压和右心室射血分数保持不变。舒张末期和收缩末期容积高度相关（r2 = 0.98，P < 0.001）。
改良的热稀释法可可靠评估心输出量和右心室功能。在静脉-动脉体外膜肺氧合脱机过程中，即使右心室功能稳定，右心室也会扩张，这可能是由于静脉回流增加所致。
