Neurohumoral responses to a single haemodialysis in chronic renal patients

The effect of volume reduction on vasoactive substances and their role in e stimating dry weight in haemodialysis patients was studied. Plasma atrial n atriuretic peptide (ANP), catecholamines, antidiuretic hormone, renin activ ity and serum aldosterone were measured in 12 patients before and after bic arbonate haemodialysis. Haemodynamical changes were registered and cardiac function and diameter of the inferior vena cava were measured by echocardio graphy before and after dialysis. Plasma concentration of ANP was significa ntly reduced by haemodialysis from 209 +/- 51 to 69 +/- 13 pg mL(-1) (n = 1 2, P < 0.05), whereas concentrations of the other hormones were unchanged. The change in the concentration of ANP did not have significant correlation with weight reduction. The concentration of ANP correlated positively with the diameter of the inferior vena cava (r = 0.70, P < 0.05) after dialysis , but not before dialysis. The concentration of ANP before or after haemodi alysis dr its change during dialysis did not correlate with any other bioch emical parameter. The results show that plasma ANP level is decreased after volume reduction in patients with chronic renal failure, whereas other hor monal systems are unresponsive. However, plasma concentration of ANP seems to have no role in estimating dry weight in chronic haemodialysis patients.