Abstract: 【Abstract】Objective To analyze the characteristics of blood pressure fluctuation during hemodialysis sessions in maintenance hemodialysis (MHD) patients, and to explore the correlation with volume load. Methods A total of 231 MHD patients admitted to the blood purification center of Hangzhou Traditional Chinese Medicine Hospital from December 2017 to June 2018 were enrolled in this study. According to the blood pressure variation during dialysis sessions, they were divided into hypertension group (△SBP ≥10mmHg), stable group (-20mmHg＜ △SBP ＜10mmHg) and hypotension group (△SBP ≤-20mmHg). The volume indicators of overhydration (OH), intracellular water (ICW), extracellular water (ECW) and total body water (TBW) were measured before and after the sessions by using bioelectrical impedance. General clinical data and laboratory indicators were also recorded. Results ①There were 43 patients (19%) in the hypertension group, 119 patients (51%) in the stable group, and 69 patients (30%) in the hypotension group. In the hypertension group, blood pressure reached the peak after the end of dialysis sessions. In the hypotension group, blood pressure was at the lowest level in the third hour in dialysis sessions, followed by a slight increase. ②Compared with the stable group, ultrafiltration volume was lower in the hypertension group (t=3.861, P＜0.001), and was higher in the hypotension group (t=3.885, P＜0.001). ③ Compared with the stable group, post-dialytic OH and ECW/TBW were higher in the hypertension group (t=2.386, P=0.018; t=2.317, P=0.021). ROC analysis showed that the area under the curves of post-dialytic OH and ECW/TBW to determine hypertension were 0.621 (95% CI: 0.546～0.697, P=0.004) and 0.604 (95% CI: 0.526～0.682, P=0.012) respectively. Conclusion Unstable blood pressure during hemodialysis sessions was frequently seen in MHD patients. In the hy-potension group, blood pressure reduced to the lowest in the third hour in dialysis sessions, suggesting that ultrafiltration volume is related to the hypotension. In the hypertension group, blood pressure reached a peak after dialysis, suggesting the presence of chronic volume overload, especially the extracellular water overload.

Key words: Renal dialysis, Bioelectrical impedance, Volume, Blood pressure