AUTONOMIC FUNCTION IN PATIENTS ON CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

Objective: To investigate sympathetic function in the peripheries of p atients on chronic ambulatory peritoneal dialysis (CAPD) using noninva sive techniques.Design: Comparison of peripheral blood flow responses In sympathetic vasoconstrictor reflexes in CAPD patients and matched c ontrol subjects. Setting: Tertiary care hospital and research institut ion. Patients: Twenty-three clinically stable CAPD patients and 23 con trol subjects matched for age, sex, and drug therapy. Main Outcome Mea sures: Sympathetic activity assessed from the reductions in hand and f oot blood flow induced by a deep breath and by body surface cooling. C ardiac autonomic activity measured by the changes in heart rate produc ed by deep breathing, a Valsalva maneuver, and standing from lying. Re sults: A deep breath induced mean decreases in hand blood flow of 65.1 % in the patients and 82.8% in their matched controls. Corresponding r eductions in the foot were 46.0% and 70.0%. Body surface cooling reduc ed mean hand blood flow by 50.3% in the patients and 71.8% in the cont rol subjects. Corresponding values in the foot were 26.7% and 43.6%. T he differences in response between the patients and their matched cont rol subjects were all significant (p < 0.01). Cardiac autonomic functi on assessed by standard tests of heart rate variability was significan tly impaired in the patients compared with the control subjects in two of the three tests used (p < 0.001). Conclusions: Cardiovascular auto nomic impairment can affect the peripheral circulation as well as the heart in patients on dialysis, and this may have implications for card iovascular homeostasis.