INTRADIALYTIC HYPERTENSION .1.

L.F. is a 64-year-old man with longstanding hypertension and non-insulin-dependent diabetes mellitus leading to end-stage renal disease (ESRD) who has been stable on hemodialysis for two years. His medications include long acting nifedipine 90 mg/day which he takes at night and clonidine 0.2 mg twice a day, including a morning dose taken prior to dialysis. His dialysis prescription, delivering a Kt/V of 1.3 is 3 hr with an F80 dialyzer at 400 ml/min blood flow through an AV graft. Dialysate composition is Na of 140 meq/l, K of 2 meq/l, Ca of 3 mEq/l, and NaHCO3 of 37 meq/l at a temperature of 35-degrees-C. The patient's interdialytic weight gains average 2-3 kg. During five consecutive dialysis sessions, the patient's blood pressure (BP) rose from a mean predialysis value of 150/90 to 170/102 after 1 hr and 180/112 after 2 hr on dialysis. Ultrafiltration (UF) was controlled at 800-1000 cc/hr. He remained asymptomatic, and elevated BP responded rapidly to nifedipine 10 mg PO. There seemed to be nothing unusual about these dialysis treatments: weight gain was not excessive and predialysis hematocrit varied between 29% and 31%.