Immunoreactive parathyroid hormone after volume change in normo- and hypotensive hemodialysis patients

The effects of reduced blood volume during hemodialysis on circulating immunoreactive parathyroid hormone (PTH) were determined in relation to changes in blood pressure and heart rate in normo- and hypotensive patients with end stage renal failure. During dialysis the plasma concentration of PTH did not change in normotensives, while PTH increased significantly in patients with a fall in blood pressure during a 25% reduction in effective intravascular volume. The blood volume was measured continuously during hemodialysis using the authors' hemoglobin measurement system. The decrease in blood volume in both groups was comparable. The results suggest that secretion of PTH during hemodialysis may play a role in hemodynamic instability during hemodialysis.