The effects of haemodialysis on cerebral blood flow.
Cerebral blood flow (CBF ml/100g/min) was measured by 133Xenon in 24 patients before and after haemodialysis (HD) and in 27 normal persons. A wide scatter of the absolute CBF values were observed to correlate with the haematocrit, whereas blood pressure, pCO2 and weight loss during HD did not. Before HD, when compared with the control group, the patients showed a distinct elevation of CBF due to the severe anaemia of this group. Though there was only a slight increase in haematocrit post-dialysis a return to normal of the post-dialysis CBF was observed. In order to achieve comparative data the CBF values were corrected mathematically to a normal haemoglobin (160g/L) and the adjusted mean pre-dialysis CBF value was within the normal range and decreased to the lowest limit of normal after HD. A significant decline in CBF was observed with increasing age and length of time on HD. When compared with normal the age-dependent decline was about twice as high and showed a 10-fold decrease with the time on HD treatment. When we grouped the patients with regard to the CBF values the following results were obtained: in eight patients CBF was elevated before HD and showed a return to normal after HD. These were younger patients with greater predialysis over-hydration and lower blood pressure. A distinctly reduced CBF was observed in nine patients and remained unchanged after HD. This group included older patients with a higher blood pressure. The reaction of CBF suggests three types of patients with different vascular reactivity to fluid excess: young normotensive patients with high vascular fluid storage capacity, patients with hypertensive vascular reactivity and patients with vascular damage.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology / Q000628:therapy; D008875:Middle Aged; D006435:Renal Dialysis
D006454:Hemoglobins