- 一般社団法人 日本血栓止血学会
- 血液と脈管 (ISSN:03869717)
- vol.7, no.2, pp.146-150, 1976
Apparent blood viscosity was measured on freshly shed blood from 127 healthy subjects, ages 21 to 88, and patients hospitalized in Tokyo Metropolitan Yoikuin Geriatrics Hospital, over age 60. Determination of blood viscosity was performed at 37°C using rotational viscometer at shear rates between 0.07 and 4.6sec<sup>-1</sup>.<br>Mean blood viscosity in 43 healthy older subjects over age 60 (mean age: 74±6) was 45±25cp at 0.07sec<sup>-1</sup> and 8±2cp at 4.6sec<sup>-1</sup>, respectively. Yield stress was calculated from Casson plot at very low shear rates (between 0.44 and 0.07sec<sup>-1</sup>) by the method of least squares. Mean value of yield stress in the healthy older subjects was 0.011 dynes/cm<sup>2</sup>. Blood viscosity in the healthy subjects was significantly correlated with hematocrit values. Yield stress in these subjects was also correlated with hematocrit values and blood viscosity at very low shear rates. In these healthy subjects, blood viscosity, yield stress and hematocrit values were highest in the group at age 30-39. Blood viscosity and yield stress showed a slight decline with age in the healthy older subjects.<br>In the hospitalized patients, blood viscosity was higher than 70cp at 0.07sec<sup>-1</sup>, and/or higher than 11cp at 4.6sec<sup>-1</sup> in 107 measurements (86 cases) out of 1443 determinations from December 1973 to October 1974. These patients with blood high viscosity included 12 cases of cancer (one of them was accompanied with disseminated intravascular coagulation (DIC); three of them developed DIC thereafter), 5 cases of acute myocardial infarction, 4 cases of acute cerebral infarction, 5 cases of angina pectoris, 6 cases of old myocardial infarction, 18 cases of old cerebrovascular diseases, 11 cases of diabetes mellitus, and 5 cases of stress polycythemia or polycythemia vera. In these cases, viscosity at 4.6sec<sup>-1</sup> was significantly correlated with hematocrit values, whereas viscosity at 0.07sec<sup>-1</sup> was not. All patients with blood high viscosity and relatively low hematocrit values suffered from cancer. In 6 cases of acute myocardial, cerebral of renal infarction, in whom changes in blood viscosity, yield stress and hematocrits were investigated before and after the development of infarction, changes in blood viscosity and yield stress were parallel with hematocrits.<br>From these results, it was concluded that high hematocrits caused blood high viscosity and were regarded as one of the risk factors in the pathogenesis of thrombosis, although the other factors than hematocrits might also influence blood viscosity at very low shear rates.