Effect of partial cold-loading on peripheral circulation

The purpose of this study is the effect of partial cold-loading on whole body peripheral circulation. The body surface peripheral circulation in 24 cases (25 years old to 86 years old, the average was 64.3 years) who were suffering coldness, numbness or pain in their feet was examined using Laser-Doppler blood flowmetry. The peripheral circulation at the base of the 2nd toe of the right foot was estimated after the foot was submerged and cooled for 5 min in a water bath at 20°C (i. e. cold-loading). At the same time, the distant body surface peripheral circulation was estimated at the base of the 2nd finger of the right hand. Simultaneous observations were made of blood flow, blood mass and blood velocity. The peripheral blood flow of the upper limbs at a room temperature of 20°C (pre-loading) was 5.00 ml/min 100 9 tissue on average. The average blood rnass was 287 and the average blood velocity was 0.516. On the other hand, the average peripheral blood flow of the lower limbs was 2.23, the average blood mass was 149 and the average blood velocity was 0.574. This result shows that the blood flow and blood mass of the upper limbs were more than in the lower limbs. The average blood flow at the upper limbs decreased to 3.69 from 5.00 (or at 26.2% ) when the lower limbs were submerged and cooled for 5 min in a water bath at 20°C (i. e. cold-loading). On the other hand, blood flow of the lower limb was 1.51 m l under a condition of cold-loading, and decreased 32.3% from 2.23. Blood mass of the upper limb was 241 on average and decreased 16.0% from 287. Blood mass of the lower limb was 113 on average and decreased 24.2% from 149. There was no difference between blood velocity of the upper limb under the conditions of room temperature at 20°C (0.516) and cold-loading (0.501). However, blood velocity of the lower limb increased to 0.642 from 0.574. After the end of cold loading, there was some tendency for blood flow, blood rnass and blood velocity to return to the amount at pre-loading. Twenty minutes after the end of cold-loading, blood flow increased to 5.74 (14.8% ) compared with pre-loading (5.00). However, blood flow of the lower limb remained at only 83.9% (1.87) of the amount at pre-loading (2.23). These results show that partial cold-loading of the lower limb had a quantitative effect on the distant peripheral circulation. The speculated mechanism of this phenomenon is that it to protects against loosing body heat from the body surface under the conditions of local cold-loading. Our body has defense mechanisms to decrease whole body peripheral circulation to protect against loosing body heat.

局所寒冷負荷の全身の末梢循環に及ぼす影響について検討する目的で，下肢の20℃冷水負荷時における上肢末梢循環の変化をレーザードプラー血流計を用いて数量的に測定し検討を行なった。症例は，下肢に冷え症，しびれ感を有した25歳から86歳までの24症例（平均年齢64.3歳）であった。下肢，上肢の末梢循環を20℃冷水負荷時に，末梢血流量，血液量，血流速度について観察した。上肢の末梢血流量は20℃室内安静時平均5.00mβ/min/100g tissue，血液量は287，血流速度は0.516であった。下肢は血流量2.23，血液量は149，血流速度は0.574であった。上肢の血流量，血液量ともに下肢より多いことが示された。しかし同一症例における上肢と下肢との間の血流量，血液量，血流速度に相関関係は認めなかった。下肢の20℃ 冷水負荷中の上肢の血流量は平均3.69で有意に低下（26.2％）した。下肢はその間1．51で有意に低下（32.3％）した。上肢の血液量は平均241で有意に低下（16．0％）した。下肢はその間113で有 意に低下（24.2％）した。上肢の血流速度は平均0.501で不変であった。下肢はその間0．642で有意に増加（11.8％）した。冷水負荷直後よりそれぞれ負荷前に復帰する傾向を示した。負荷後20分では上肢の血流量は平均5．74で負荷前値に比べて増加（14.8％）傾向を示した。下肢は1.87で負荷前値に比べて低値（83.9％）に留まる傾向にあった。下肢の冷水負荷は上肢の末梢循環にも影響を及ぼすことが数量的に示された。局所の寒冷負荷による体温の低下を防ぐために反射的に全身の皮膚の末梢循環量を低下させていることが示された。