[Clinical control study of dialysates with different concentrations of calcium on blood pressure in patients under hemodialysis for prolonged period].

Objective: To investigate the changes in blood pressure in hemodialysis patients treated with low calcium dialysate or high calcium dialysate for long time.

Methods: Fifteen patients undergoing hemodialysis were enrolled in this study. High calcium dialysate (1.75 mmol/L, Dca1.75) was first used for 6 months, then low calcium dialysate (1.25 mmol/L, Dca1.25) was used for 6 months. Serum calcium, phosphate, blood urea nitrogen, and creatinine were measured, blood pressure was recorded before and after hemodialysis at the beginning, and also at 1, 2, 3 and 4 hours after hemodialysis.

Results: Compared with that before the treatment, systolic and diastolic blood pressure lowered significantly after single low calcium hemodialysis for 4 hours (both P<0.05), while systolic and diastolic blood pressure rose significantly after single high calcium hemodialysis (both P<0.05). Systolic blood pressure changed more obviously after two hemodialyses (both P<0.05). Changes in systolic, diastolic and mean blood pressure were positively related to changes in serum total calcium (r(1)=0.326, P(1)=0.054; r(2)=0.383, P(2)=0.037; r(3)=0.391, P(3)=0.032). During 6 months of hemodialysis with low calcium dialysate, blood pressure lowered slightly with no significant difference in it (P>0.05), while systolic blood pressure rose during 6 months of hemodialysis with high calcium dialysate (P<0.05). Changes in systolic blood pressure were significantly different between two groups using dialysates with different calcium concentrations (P<0.05).

Conclusion: Systolic blood pressure and incidence of hypertension decrease after single low calcium hemodialysis.