Estimation of representative blood pressure values in haemodialysed children

The diagnosis of hypertension in patients on chronic haemodialysis is not easy because the blood pressure changes as a consequence of therapy (haemodialysis) and attenuated circadian rhythm of blood pressure is often present. The estimation of representative blood pressure levels is difficult because it is not known whether blood pressures measured before starting or after completion of haemodialysis are predictive for the average interdialytic blood pressure. Our group of patients consisted of 18 children with endstage renal failure, aged 13.5 +/- 3.2 years, treated with chronic haemodialysis from 0.1 to 110 (mean 25.8, median 19) months. Ambulatory blood pressure monitoring was performed during 44 h interdialytic period. Blood pressure was also measured with sphygmomanometer before starting and after completion of heamodialysis. The average blood pressure values for the last ten haemodialyses were evaluated as well. Multiregression analysis showed significant correlation between interdialytic blood pressure (systolic and diastolic) and blood pressures measured before haemodialysis (r = 0.74; p < 0.001, r = 0.78; p < 0.001, respectively) and after haemodialysis (r = 0.76; p < 0.01, r = 0.6; p < 0.05, respectively). Statistically high correlation between these blood pressures was also confirmed for the average blood pressure values for the last 10 haemodialyses (r = 0.78; p < 0.001, r = 0.75; p < 0.001 and r = 0.78; p < 0.001, r = 0.86; p < 0.001, respectively). Our findings show that blood pressures measured before starting or after completion of haemodialysis give good information about interdialytic blood pressure in children on chronic haemodialysis.