Atrial natriuretic factor and right atrial pressure in patients undergoing chronic haemodialysis

To quantitate the mutual relationship between central venous pressure (CVP) and circulating atrial natriuretic factor (ANF) during haemodialysis, nine end-stage renal failure patients on chronic haemodialysis underwent ultrafiltration (UF) and biochemical correction (3 h) separated by 1 h (no dialysis, ND). During UF CVP and circulating ANF decreased significantly in all patients from basal levels (0.5±1.0 vs 5.4±2.0 mmHg and 58±16 vs 95±19 pmol/l respectively,P<0.01 for both), while microhaematocrit increased significantly (29.5±1 vs 26.0±1%,P<0.01). During ND, CVP and ANF rose significantly (P<0.05 for both) in seven of the nine patients, while microhaematocrit returned towards basal values. In two patients CVP did not change during ND and circulating ANF remained unchanged. A significant correlation between CVP and circulating ANF was found (end-basal to end-UF,r=0.72,P<0.05; end-UF to end-ND,r=0.77,P=0.025;n=7). As expected, during biochemical correction plasma creatinine and K⁺ decreased significantly and consistently in all the patients (from 875±74 to 400±56 mol/l and from 4.7±0.07 to 4.0±0.04 mEq/l, respectively;n=9,P<0.01 for both) as did body weight during UF (65.6±7 vs 67±5 kg;n=9,P<0.05). No significant changes were seen for systolic and diastolic blood pressure, heart rate and plasma renin activity at any time. Our data provide further evidence that the regulation of circulating ANF is synchronized with changes in CVP. They also quantitate the mutual relationship between CVP and ANF in end-stage renal failure.