Abstract: Objective To investigate the changes of blood pressure, serum calcium, phosphate and parathyroid hormone in hemodialysis patients after being treated with different calcium dialysate (1.25mmol/L and 1.75mmol/L) for 6 months Methods Twenty patients were enrolled in this study. These patients firstly received high calcium dialysate(1.75mmol/L) for 6 months, then accepted low calcium dialysate (1.25mmol/L)therapy for 6 months while other therapy remained.Unchanged blood pressure, serum calcium, phosphate, parathyroid hormone and alkaline phosphatase were measured before and after one dialysis session at the beginning,3 and 6 months later. Results Serum calcium level decreased 7.5 percent(P＞0.05), blood pressure decreased (P＜0.05)and parathyroid hormone increased(P＜0.05)in post-dialysis compared with pre-dialysis for single low calcium dialysis; While blood pressure and serum calcium increased (P＜0.05) and parathyroid hormone decreased(P＞0.05) in post-dialysis for single high calcium dialysis. During 6 months with low calcium dialysate, serum calcium and blood pressure gradually dicreased, while serum parathyroid hormone gradually increased. However these changes didn’t show statistical difference(P＞0.05). But serum alkaline phosphatase increased remarkedly (P＜0.05),serum phosphate and calcium-phosphate product decreased remarkedly(P＜0.05). The changes of systolic blood pressure, parathyroid hormone and alkaline phosphatase due to different calcium dialysate showed statistical difference(P＜0.05). Conclusion Serum parathyroid hormone increased with single low calcium dialysis. Calcium load, systolic blood pressure and serum calcium-phosphate decreased, serum parathyroid hormone increased, serum alkaline phosphatase increased remarkedly after 6 months dialysis with low calcium dialysate contrasted with high calcium dialysate.

Key words: Calcium, Dialysate, Parathyroid hormone