Sanda Sardelić, Dragan Ljutić, Jugoslav Bagatin, Nediljko Pivac, Zvonko Rumboldt
Effect of noradrenaline on superficial hand veins on chronic hemodialysis patients

The purpose of the present study was to answer the question whether an inadequate venoconstriction could be the reason of impaired hemodynamics in dialysis patients. Therefore, the responsiveness of veins was assessed in 18 patients with chronic renal failure on acetatate dialysis. Nine uremics (4 males and 5 females) aged 48.6±9.1 years with symptomatic hypotension during dialysis and with a drop in the standing blood pressure after dialysis of more than 30/10 mm Hg formed the hypotension prone group, while the remaining nine (5 males and 4 females) aged 49.1±9.5 years were considered normotensive. Patients with supine blood pressure higher than 150/90 mm Hg after dialysis were categorized as hypertensives. A control group consisted of 13 healthy volunteers. The study was performed the day after dialysis on dorsal hand veins (of the arm without AV fistula) using the venoconstriction test. Increasing doses of injected noradrenaline (1, 2, 5, and 10 mg) produced a weak venoconstriction in hypotension prone patients [medians: 132, 1132, 789, and 1390 venoconstriction units (VCU)] in comparison with normotensives (1974, 2280, 3395, 4895 VCU) and controls (800, 1600, 2105, 2450 VCU). It was concluded that an attenuated venoconstriction following sympathetic stimulation could be a possible reason for hypotensive reactions in one group of uremic dialysis patients. Exaggerated vascular responsiveness, as seen mostly in hypertensives, could partly contribute to the pathogenesis of dialysis-resistant hypertension. The hypotensive reactions during dialysis should therefore not be treated with sympatomimetics, but with saline infusions and elastic bandages on the lower extremities at the end of the dialysis.

Key words: noradrenaline, venoconstriction, uremia, hemodialysis.