Khan F, Carnochan F M, Abbot N C, Wilson S B
Vascular Laboratory, Ninewells Hospital and Medical School, Dundee, Scotland.
Int J Microcirc Clin Exp. 1991 Feb;10(1):43-53.
The effects of raised tissue oxygen levels on reactive hyperaemia (RH) in the skin following arterial occlusion of short duration were investigated. Oxygen levels were increased by breathing 100% oxygen at 1 and 2 atmospheres absolute (ATA) in a hyperbaric chamber. Superficial skin blood flow and oxygen tension were measured throughout using a laser Doppler flowmeter and a transcutaneous oxygen monitor. The basal pre-occlusion and the maximum post-occlusion blood flows (Flb and Flmax), the time taken for flow to fall to half maximum (TR1/2), and the time for flow to return to its basal level (TR) were measured. Pre- and end-occlusion transcutaneous oxygen levels were also recorded. Oxygen breathing at 1 ATA significantly reduced TR1/2 (p less than 0.05) and at 2 ATA significantly reduced TR1/2 and TR (p less than 0.005 and p less than 0.0001) compared with control measurements during air breathing at 1 ATA. Flmax was not significantly reduced breathing oxygen at 1 or 2 ATA. These findings support the view that maximum post-occlusion blood flow in superficial skin is determined mainly by myogenic mechanisms, whereas the recovery of blood flow to basal levels is influenced largely by oxygen tension. We conclude that the direct vasoconstrictor effect of high oxygen levels is small and that the faster recovery at high tissue oxygen tensions may result from a decrease in vasodilators formed during hypoxia.
研究了短时间动脉闭塞后组织氧水平升高对皮肤反应性充血（RH）的影响。在高压舱中通过呼吸1个和2个绝对大气压（ATA）的100%氧气来提高氧水平。使用激光多普勒流量计和经皮氧监测仪全程测量浅表皮肤血流和氧张力。测量基础闭塞前和闭塞后最大血流（Flb和Flmax）、血流降至最大值一半所需时间（TR1/2）以及血流恢复至基础水平所需时间（TR）。还记录了闭塞前和闭塞后的经皮氧水平。与在1个ATA空气呼吸时的对照测量相比，在1个ATA呼吸氧气显著降低了TR1/2（p<0.05），在2个ATA呼吸氧气显著降低了TR1/2和TR（p<0.005和p<0.0001）。在1个或2个ATA呼吸氧气时，Flmax没有显著降低。这些发现支持以下观点，即浅表皮肤闭塞后最大血流主要由肌源性机制决定，而血流恢复至基础水平在很大程度上受氧张力影响。我们得出结论，高氧水平的直接血管收缩作用较小，高组织氧张力下更快的恢复可能是由于缺氧期间形成的血管舒张剂减少所致。
