Effect of 2 liters of intraperitoneal dialysate on the cardiovascular system.

In 21 patients receiving continuous ambulatory peritoneal dialysis (CAPD), the effect of 2 liters of intraperitoneal dialysate on the supine and upright hemodynamics (19 patients), and the hemodynamic responses to 45 degrees head-up tilt (9 patients) were studied. Blood pressure (BP), heart rate (HR) and stroke volume (SV) (using impedance cardiography) were measured. In the supine position there was no significant difference in BP, SV, HR, derived cardiac output (CO) and peripheral resistance (PR) between "empty" (E) and "full" (F) conditions. On standing in both E and F conditions there were significant falls in systolic BP (p less than 0.001, compared with supine), SV and CO (p less than 0.05) accompanied by an increase in HR (p less than 0.001) but no significant change in peripheral resistance nor diastolic BP. The fall in systolic BP was greater in the E condition (from 149.3 +/- 4.5 mmHg to 134.6 +/- 5.9 in E, from 148.8 +/- 4 mmHg to 140.8 +/- 5.0 in F, p less than 0.001) and was accompanied by a bigger rise in HR (from 80.2 +/- 4.3 beat/min to 91.8 +/- 5.3 (E), from 79.4 +/- 4.4 to 87.7 +/- 5.2 (F, p less than 0.001). On tilting in 13 normal subjects there was an increase in diastolic BP (76.7 +/- 2.0 mmHg to 81.4 +/- 0.6, p less than 0.01), HR (63.3 +/- 2.4 beat/min to 73.6 +/- 1.0, p less than 0.01) and PR (13.4 +/- 1.0 mmHg/l/min to 21.3 +/- 0.2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)