1979 Volume 16 Issue 6 Pages 528-535
To elucidate a pathogenetic mechanism of stress erythrocytosis in the aged, hematological study was performed in 13 patients above 60 years old, diagnosed as a stress erythrocytosis. The results obtained were as follows:
1) All of these patients were male. Venous hematocrit (Ht) value of these patients was always higher than 48% prior to admission. However, the circulating red cell volume measured using 51Cr tagging method was within the normal limit in all cases, while the plasma volume measured with T-1824 or 125I-RISA decreased comparing with the control value measured in healthy aged men in 11 out of 12 cases. A ratio of whole body Ht to venous Ht was markedly reduced in all cases.
2) Change of venous Ht value after admission was followed up in 10 cases. Either a prompt or a gradual decrease in Ht value was observed one or two days after admission, and a high Ht value diappeared during three to five weeks after admission in all cases. Furthermore, change of plasma volume was investigated in three out of these cases at the times of both high and normal Ht values, respectively. It increased at various drgrees in all cases as a high Ht value normalized.
Relationship of high Ht value to blood pressure was studied in a course of the time after admission in ten cases. No significant relationship between Ht values and systolic or diastolic blood pressure was observed in these cases.
3) Viscosity of whole blood was markedly elevated at the shear rate of 0.00062 or 0.073sec-1 in ten out of 12 cases and of 4.6 sec-1 in all cases.
From these findings it is indicated that there are both a contraction of plasma compartment and an intravascular shift of the plasma and red cells in stress erythrocytosis. Since stress erythrocytosis brings out an elevation of blood viscosity, it is an important risk-factor for an occurrence of thromboembolic disease in the aged. Therapeutic procedure should be taken against a stress erythrocytosis in the aged.