Abbot N C, Beck J S
Pathology Department, University of Dundee, Ninewells Hospital and Medical School, UK.
Int J Microcirc Clin Exp. 1993 Feb;12(1):89-98.
The Biological Zero (BZ) signal in laser Doppler flowmetry was recorded during temporary occlusion of the arterial circulation to the limb by a blood pressure cuff inflated suprasystolically for 2 min. The non-thermoregulatory skin at the ankle was compared with the thermoregulatory skin over the toe pad in patients with lower limb arterial obstructive disease, elderly controls without arterial disease and young healthy adults under cool (15-17 degrees C) and warm (25-27 degrees C) ambient conditions. The absolute BZ values did not differ significantly within the three groups at the two room temperatures. However the resting laser Doppler flowmetry signal (LDflux) was consistently higher under warm than cold room temperatures: these differences were much greater at the toe than at the ankle. Accordingly, the relative size of BZ, expressed as a percentage of the resting LDflux, was least over the toe in a warm room (5-10%) and greatest over the malleolus (59-83%) in the cold room. The changes during the evolution of a positive tuberculin skin reaction were followed as a model of chronic inflammation in man. The resting LDflux rose 10 fold (from 0.3 to 3.4V) while the change in the BZ was minor (0.16-0.2V). Thus the rise in LDflux in a fully developed tuberculin reaction was approximately 30X greater than that for the corresponding BZ. Concurrent measurements of the alternative output from the laser Doppler flowmeter (CMBC) showed in a similar pattern. Since the BZ signal can be a substantial proportion of the resting LDflux measurement, we support the recommendation that the BZ should be measured wherever possible and practicable, for subtraction from the observed LDflux to assess the true flow: 'raw' LDflux measurements should be interpreted with extreme caution, particularly at relatively low resting LDflux levels.
通过一个超收缩压充气2分钟的血压袖带暂时阻断肢体的动脉循环，记录激光多普勒血流仪中的生物零（BZ）信号。在凉爽（15 - 17摄氏度）和温暖（25 - 27摄氏度）的环境条件下，比较了下肢动脉阻塞性疾病患者、无动脉疾病的老年对照者以及年轻健康成年人脚踝处的非体温调节皮肤和趾垫上的体温调节皮肤。在两个室温下，三组内的绝对BZ值没有显著差异。然而，静息激光多普勒血流仪信号（LDflux）在温暖室温下始终高于寒冷室温：这些差异在趾部比在脚踝处大得多。因此，以静息LDflux的百分比表示的BZ相对大小，在温暖房间的趾部最小（5 - 10%），在寒冷房间的内踝处最大（59 - 83%）。作为人类慢性炎症的模型，跟踪了结核菌素皮肤阳性反应演变过程中的变化。静息LDflux上升了10倍（从0.3到3.4V），而BZ的变化很小（0.16 - 0.2V）。因此，在完全发展的结核菌素反应中，LDflux的上升比相应的BZ大约大30倍。激光多普勒血流仪的替代输出（CMBC）的同步测量显示出类似的模式。由于BZ信号可能占静息LDflux测量值的很大比例，我们支持以下建议：只要可能且可行，就应测量BZ，以便从观察到的LDflux中减去，以评估真实血流：“原始”LDflux测量值的解释应极其谨慎，特别是在静息LDflux水平相对较低时。
