Rendell M S, Wells J M
The Creighton Diabetes Center, Omaha, NE 68131, USA.
Arch Phys Med Rehabil. 1998 Nov;79(11):1451-5. doi: 10.1016/s0003-9993(98)90243-x.
There is reason to question whether hyperemia after pressure occlusion is caused solely by local ischemia. This study quantitatively compared the response to the two forms of occlusion on the finger.
Blood flow was measured by laser Doppler continuously before, during, and for 40 minutes after a 2-minute occlusion of flow at the finger dorsum and at the plantar surface of the finger tip (finger pulp), which has a much higher arteriolar density than the dorsum. Occlusion to the same low level was carried out either with a cuff at the base of the finger or by direct pressure of the laser Doppler probe head. Comparison experiments were performed with the probe head heated to 44 degrees C to elicit maximal local vasodilation.
Outpatient clinic.
Eleven healthy volunteers.
Magnitude and duration of skin blood flow after occlusion.
Cuff occlusion at the base of the finger produced a typical, short-lived hyperemic response at both finger dorsum and finger pulp. The peak level at finger dorsum was 17.6 +/- 1.4mL/min/100g, approximately a twofold increase over the baseline flow level. The duration of the hyperemic response was 3.6 +/- 0.8 minutes. The baseline flow at the finger pulp was three times greater than at the finger dorsum, and peak flow after occlusion was also three times higher (44.3 +/- 2.6 mL/min/100g). The duration of hyperemia at finger pulp was 4.2 +/- 0.9 minutes. After pressure occlusion at the finger dorsum the hyperemic peak was higher (26.7 +/- 4.2 mL/min/100g; p < .05) and the duration of hyperemia was four times longer (16.9 +/- 2.3 minutes; p < .01) than after cuff occlusion. At the finger pulp, the pressure-induced hyperemic peak was also greater than the peak after cuff occlusion (56.3 +/- 1.7mL/min/100g; p < .05), with a longer duration than after cuff occlusion (11.1 +/- 1.1min; p < .01). Thermal stimulation significantly reduced the differences between cuff- and pressure-induced occlusion. There was a slow increase in flow over the 40-minute monitoring period. The maximal flow reached was approximately 100mL/min/100g at both finger dorsum and finger pulp. At both sites, however, the maximal flow level was attained more rapidly than the control condition without prior occlusion.
These results confirmed that the pressure-induced hyperemic response is greater and of longer duration than that produced by flow ischemia alone. Thermal stimulation essentially abolishes the differences, suggesting that there is a common mechanism of vasodilatation. The mechanistic differences between pressure-induced and ischemic hyperemia remain to be determined.
有理由质疑压力阻断后的充血是否仅由局部缺血引起。本研究定量比较了手指对两种阻断形式的反应。
在手指背侧和指尖掌面（指腹）进行2分钟血流阻断前、阻断期间及阻断后40分钟，用激光多普勒连续测量血流。指腹的小动脉密度比背侧高得多。通过手指根部的袖带或激光多普勒探头头部的直接压力将血流阻断至相同的低水平。将探头加热至44摄氏度以引发最大程度的局部血管舒张，进行对比实验。
门诊诊所。
11名健康志愿者。
阻断后皮肤血流的幅度和持续时间。
手指根部的袖带阻断在手指背侧和指腹均产生了典型的、短暂的充血反应。手指背侧的峰值水平为每分钟每100克17.6±1.4毫升，比基线血流水平增加了约两倍。充血反应的持续时间为3.6±0.8分钟。指腹的基线血流是手指背侧的三倍，阻断后的峰值血流也是其三倍（每分钟每100克44.3±2.6毫升）。指腹充血的持续时间为4.2±0.9分钟。手指背侧压力阻断后的充血峰值更高（每分钟每100克26.7±4.2毫升；p<0.05），充血持续时间比袖带阻断长四倍（16.9±2.3分钟；p<0.01）。在指腹，压力诱导的充血峰值也高于袖带阻断后的峰值（每分钟每100克56.3±1.7毫升；p<0.05），持续时间比袖带阻断后更长（11.1±1.1分钟；p<0.01）。热刺激显著缩小了袖带阻断和压力阻断之间的差异。在40分钟的监测期内血流缓慢增加。手指背侧和指腹达到的最大血流约为每分钟每100克100毫升。然而，在两个部位，最大血流水平的达到速度均比未预先阻断的对照情况更快。
这些结果证实，压力诱导的充血反应比单纯血流缺血引起的充血反应更大且持续时间更长。热刺激基本上消除了差异，表明存在共同的血管舒张机制。压力诱导充血和缺血性充血之间的机制差异仍有待确定。
