Blood pressure during the interdialytic period in haemodialysis patients: estimation of representative blood pressure values.

The estimation of representative blood pressure (BP) levels is difficult in haemodialysis (HD) patients as it is not known whether pre- or postdialytic blood pressure are predictive for the average interdialytic BP. Furthermore, the day-night BP rhythm can be disturbed in HD patients. Therefore, in this study, BP was measured during the interdialytic period using non-invasive ambulatory BP measurements in four hypotensive, six normotensive, and 12 hypertensive HD patients. It was assessed whether pre- or postdialytic BP was representative for the average interdialytic BP. Furthermore, the nocturnal BP reduction was compared between HD patients, seven normotensive controls and eight treated subjects with essential hypertension. Postdialytic BP was superior to predialytic BP in predicting the average BP during the interdialytic period. BP did not differ significantly between day 1 and day 2 of the interdialytic period but increased rapidly in the hours before dialysis. Weight gain (corrected for actual body-weight) did not correlate significantly with the increment in systolic BP (r = 0.21; P = 0.2) or diastolic BP (r = -0.02; P = 0.5) during the interdialytic period. The nocturnal decline in systolic BP was significantly attenuated (P less than 0.001) in hypertensive HD patients compared with normotensive controls. The nocturnal reduction in diastolic BP was significantly less in hypotensive (P less than 0.001) and normotensive (P less than 0.001) HD patients compared with normotensive controls and in hypertensive HD patients compared with normotensive (P less than 0.001) and hypertensive (P less than 0.001) controls.(ABSTRACT TRUNCATED AT 250 WORDS)