Background. Relative blood volume (RBV) monitoring is widely used in hemodialysis (HD) patients, yet the association between intradialytic RBV and mortality is unknown.
Methods. Intradialytic RBV was recorded once/min during a 6-month baseline period; all-cause mortality was noted during follow-up. RBV at 1, 2 and 3 h into HD served as a predictor of all-cause mortality during follow-up. We employed Kaplan-Meier analysis, univariate and adjusted Cox proportional hazards models for survival analysis.
Results. We studied 842 patients. During follow-up (median 30.8months), 249 patients (29.6%) died. The following hourly RBV ranges were associated with improved survival: first hour, 93-96% [hazard ratio (HR) 0.58 (95% confidence interval (CI) 0.42-0.79)]; second hour, 89-94% [HR 0.54 (95% CI 0.39-0.75)]; third hour, 86-92% [HR 0.46 (95% CI 0.33-0.65)]. In about onethird of patients the RBV was within these ranges and in twothirds it was above. Subgroup analysis by median age ( 61 years), sex, race (white/nonwhite), predialysis systolic blood pressure (SBP; 130 mmHg) and median interdialytic weight gain ( 2.3 kg) showed comparable favorable RBV ranges. Patients with a 3-h RBV between 86 and 92% were younger, had higher ultrafiltration volumes and rates, similar intradialytic average and nadir SBPs and hypotension rates, lower postdialysis SBP and a lower prevalence of congestive heart failure when compared with patients with an RBV>92%. In themultivariate Cox analysis, RBV ranges remained independent and significant outcome predictors.
Conclusion. Specific hourly intradialytic RBV ranges are associated with lower all-cause mortality in chronic HD patients.
- relative blood volume
- MAINTENANCE HEMODIALYSIS
- DIALYSIS HYPOTENSION
- FLUID STATUS