Cardiac output (Q̇C) and leg blood flow (Q̇LEG) can be measured simultaneously with high accuracy using transpulmonary and femoral vein thermodilution with a single‐bolus injection. The invasive measure has offered important insight into leg hemodynamics and blood flow distribution during exercise. Despite being the natural modality of exercise in humans, there has been no direct measure of Q̇LEG while running in humans. We sought to determine the feasibility of the thermodilution technique for measuring Q̇LEG and conductance during high‐intensity running, in an exploratory case study. A trained runner (30 years male) completed two maximal incremental tests on a cycle ergometer and motorized treadmill. Q̇LEG and Q̇C were determined using the single‐bolus thermodilution technique. Arterial and venous blood were sampled throughout exercise, with continuous monitoring of metabolism, intra‐arterial and venous pressure, and temperature. The participant reached a greater peak oxygen uptake (V̇O2peak) during running relative to cycling (74 vs. 68 mL/kg/min) with comparable Q̇LEG (19.0 vs. 19.5 L/min) and Q̇C (27.4 vs. 26.2 L/min). Leg vascular conductance was greater during high‐intensity running relative to cycling (82 vs. 70 mL/min/mmHg @ ~80% V̇O2peak). The “beat phenomenon” was apparent in femoral flow while running, producing large gradients in conductance (62–90 mL/min/mmHg @ 70% V̇O2peak). In summary, we present the first direct measure of Q̇LEG and conductance in a running human. Our findings corroborate several assumptions about Q̇LEG during running compared with cycling. Importantly, we demonstrate that using thermodilution in running exercise can be completed effectively and safely.

中文翻译：

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使用热稀释法评估跑步期间的腿部血流量和心输出量


心输出量（Q̇ C ）和腿部血流量（Q̇腿）可以使用单次推注的经肺和股静脉热稀释同时高精度测量。这种侵入性测量为运动期间腿部血流动力学和血流分布提供了重要的见解。尽管 Q̇ 是人类运动的自然方式，但还没有直接测量方法腿在人类身上奔跑时。我们试图确定热稀释技术测量 Q̇ 的可行性腿探索性案例研究中的高强度跑步期间的电导和电导。一名训练有素的跑步者（30 岁男性）在自行车测力计和电动跑步机上完成了两次最大增量测试。 Q̇腿和 Q̇ C使用单次热稀释技术测定。在整个运动过程中采集动脉和静脉血样本，持续监测新陈代谢、动脉内和静脉压以及温度。参与者达到了更高的峰值摄氧量（V̇O 2峰）在跑步期间相对于骑行期间（74 vs. 68 mL/kg/min），具有相当的 Q̇腿（19.0 与 19.5 L/min）和 Q̇ C （27.4 与 26.2 升/分钟）。相对于骑自行车，高强度跑步期间腿部血管传导性更大（82 vs. 70 mL/min/mmHg @ ~80% V̇O 2峰）。跑步时股动脉血流中的“搏动现象”很明显，产生较大的电导梯度（62–90 mL/min/mmHg @ 70% V̇O 2峰）。总之，我们提出了 Q̇ 的第一个直接测量腿和跑步者的电导。 我们的发现证实了关于 Q̇ 的几个假设腿跑步时与骑车时相比。重要的是，我们证明在跑步锻炼中使用热稀释可以有效且安全地完成。