Integrative Physiology Laboratory, University of Illinois at Chicago, Chicago, Illinois, USA.
Department of Kinesiology, Iowa State University, Ames, Iowa, USA.
Exp Physiol. 2022 Apr;107(4):383-389. doi: 10.1113/EP090071. Epub 2022 Mar 17.
What is the central question of this study? It is valuable to be able to monitor disease- or treatment-related changes in the microcirculation. Laser Doppler flowmetry with local heating allows non-invasive monitoring of the skin microcirculation and its ability to vasodilate. Does reactive hyperaemia augment the increase in skin blood flow elicited by local heating? What is the main finding and its importance? The addition of reactive hyperaemia to local heating results in greater vasodilatation than heating alone. Thus, reactive hyperaemia can augment local heat-induced hyperaemia in the skin.
The skin circulation has been proposed as a model of generalized microvascular function that could be monitored non-invasively using laser Doppler flowmetry (LDF). The response to heat hyperaemia (HH) is commonly used to monitor disease- or treatment-related changes in microvascular function. We hypothesized that reactive hyperaemia would augment the increase in skin blood flow elicited by local heating. Fourteen healthy young adults were subjected to three different conditions: reactive hyperaemia (RH; skin temperature controlled at 33°C), heat hyperaemia (HH; 42°C held for 40 min) and HH+RH. Two Peltier-controlled thermomodules with LDF probes were placed on the right forearm to monitor skin blood flow continuously. A cuff was placed on the right upper arm to elicit RH by inflation to 220 mmHg for 5 min. This procedure was performed with the skin temperature at 33°C and again after 40 min of local heating to 42°C. Beat-by-beat mean arterial pressure (MAP) obtained by a photoplethysmographic sensor on the middle finger of the left hand allowed calculation of cutaneous vascular conductance (CVC) as LDF/MAP. Both HH and RH increased LDF (P < 0.0001 and P < 0.0001, respectively) and CVC (P = 0.0001 and P < 0.0001, respectively) above baseline values. The LDF and CVC values were significantly higher during HH+RH when compared with RH or HH alone (P < 0.0001). In summary, HH+RH resulted in greater vasodilatation when compared with HH or RH alone. These results indicate that RH can augment local heat-induced hyperaemia in the skin.
本研究的核心问题是什么？能够监测疾病或治疗相关的微循环变化是很有价值的。局部加热激光多普勒流量测量允许非侵入性监测皮肤微循环及其扩张能力。反应性充血是否会增加局部加热引起的皮肤血流增加？主要发现及其重要性是什么？与单独加热相比，加入反应性充血会导致更大的血管扩张。因此，反应性充血可以增强皮肤局部热诱导的充血。
皮肤循环被提出作为一种广义微血管功能的模型，可以使用激光多普勒流量测量（LDF）进行非侵入性监测。热充血反应（HH）通常用于监测疾病或治疗相关的微血管功能变化。我们假设反应性充血会增强局部加热引起的皮肤血流增加。14 名健康年轻成年人接受了三种不同的条件：反应性充血（RH；皮肤温度控制在 33°C）、热充血（HH；42°C 持续 40 分钟）和 HH+RH。两个带有 LDF 探头的 Peltier 控制热模块放置在右前臂上，以连续监测皮肤血流。右上臂上放置一个袖口，通过充气至 220mmHg 5 分钟来引起 RH。在 33°C 的皮肤温度下进行此程序，然后在 42°C 局部加热 40 分钟后再次进行。左手中指上的光电容积传感器获得的每搏平均动脉压（MAP）允许通过 LDF/MAP 计算皮肤血管传导率（CVC）。HH 和 RH 均使 LDF（P<0.0001 和 P<0.0001）和 CVC（P=0.0001 和 P<0.0001）增加，高于基线值。与 RH 或 HH 单独相比，HH+RH 时 LDF 和 CVC 值明显更高（P<0.0001）。总之，与 HH 或 RH 单独相比，HH+RH 导致更大的血管扩张。这些结果表明，RH 可以增强皮肤局部热诱导的充血。
