Serum calcium in blood pressure regulation during hemodialysis.

Frequent hypotensive episodes developed in a 56-year-old man, who was receiving long-term hemodialysis therapy, at the time he had a uremic pericardial effusion. During dialysis with an inadvertent calcium infusion, however, the mean blood pressure (BP) was sustained and even rose from 93 to 133 mm Hg. During continued dialysis to restore the serum calcium level from a peak of 17.4 to 12.0 mg/dL, mean arterial pressure decreased back to 93 mm Hg. In contrast, BP had fallen in three of six preceding dialysis treatments and five of nine subsequent dialysis treatments, all at the same ultrafiltration rate. This report suggests the importance of serum calcium to BP regulation during hemodialysis.