 During peritoneal dialysis, water is removed from the body. This sometimes occurs at rates of up to 500 mlh. During shifts with dialysate with high glucose content, an increase in blood pressure has been described. The effect upon central hemodynamics is unknown. The researchers are investigating the effects of low and high glucose dialysate and icodextrin on cardiac output, stroke volume, pulse rate and blood pressure. The researchers have hypothesized that the effects seen are induced by vasopressin. 