EFFECT OF 2 LITERS OF INTRAPERITONEAL DIALYSATE ON THE CARDIOVASCULAR-SYSTEM

Abstract

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.degree. 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 < 0.001, compared with supine), SV and CO (p < 0.05) accompanied by an increase in HR (p < 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 < 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 < 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 < 0.01), HR (63.3 .+-. 2.4 beat/min to 73.6 .+-. 1.0, p < 0.01) and PR (13.4 .+-. 1.0 mmHg/l/min to 21.3 .+-. 0.2, p < 0.001). There was a fall in SV (100.4 .+-. 7.0 ml to 63.3 .+-. 1.5, p < 0.001) and CO (6.75 .+-. 0.40 l/min to 4.61 .+-. 0.06, p < 0.01) but no significant change in systolic BP. In the 9 CAPD patients, however, there was no significant change in any of the parameters. The presence of 2 liters of intraperitoneal dialysate did not adversely affect the hemodynamics in the supine and upright positions or the ability to cope with postural stress even though the pattern of response to tilt was abnormal.