RELATIONSHIP BETWEEN BLOOD-PRESSURE DURING HEMODIALYSIS AND AMBULATORY BLOOD-PRESSURE IN BETWEEN DIALYSES

Background. Ambulatory blood pressure measurements in haemodialysis patients are relevant in view of the high cardiovascular morbidity and mortality in chronic haemodialysis patients. Methods. Twelve normotensive patients were studied from the beginning of one dialysis until the end of the next (mean 64 h, SD 19 h) using a Spacelabs oscillometric blood-pressure recorder. Results. A circadian blood pressure rhythm was present in six of the 12 patients. In seven patients the lowest pressure recorded (including the dialysis sessions) occurred 5-6 h after dialysis (late post-dialysis dip). Blood pressure did not increase sharply in the hours before dialysis although it increased slightly in the interdialytic interval as a whole, at a mean rate of 5.6 mmHg per 24 h (SD 4.1, P < 0.001). We could not find a blood pressure measurement during dialysis (or combination of measurements) which reliably reflects interdialytic blood pressure: the 95% confidence intervals were 25 mmHg or higher. Conclusion. Ambulatory blood pressure measurements are needed for adequate monitoring of the control of blood pressure in haemodialysis patients.