Assessment of dialysis dose in critically ill maintenance dialysis patients

Maintenance dialysis patients are admitted more frequently to the intensive care unit (ICU) and have higher ICU mortality than the general population. It is unclear if such dialysis patients receive adequate dialysis in the ICU setting. Using the Daugirdas formula for calculation of spKt/Vurea, single treatment delivered dialysis dose was assessed in 85 critically ill maintenance hemodialysis patients during their first ICU dialysis session. Weekly delivered spKt/Vurea was determined in the surviving 64 patients and compared with their corresponding delivered outpatient dialysis dosages. Outcome measures were ICU and in-hospital mortality and mortality at 6 and 12 months after discharge. Prescribed dose of the first ICU dialysis was a spKt/Vurea of 1.43 ± 0.11, the single treatment delivered dose was 1.02 ± 0.14. The weekly prescribed ICU Kt/Vurea was 4.25 ± 0.12 and delivered ICU Kt/Vurea was 3.48 ± 0.19. Patients with sepsis had the lowest mean spKt/Vurea values (0.87 ± 0.12). Serial measurements of delivered dialysis dose suggest that this gap is explained by variability of volume of urea distribution. ICU mortality was 25% and was related to APACHE II score, but not to delivered intermittent hemodialysis dose. Critically ill maintenance dialysis patients receive suboptimal dialysis doses. The impact of short-term underdialysis on survival of hospitalized maintenance dialysis patients remains unknown. Assessment of dialysis adequacy should be routinely performed in these patients and delivered dialysis should be tracked through the initial clinical course.