title: The lower limit of intensity to control uremia during continuous renal replacement therapy.
abstract: BACKGROUND
  The recommended lower limit of intensity during continuous renal replacement therapy (CRRT) is 20 or 25 mL/kg/h. However, limited information is available to support this threshold. We aimed to evaluate the impact of different intensities of CRRT on the clearance of creatinine and urea in critically ill patients with severe acute kidney injury (AKI).
  
  
  METHODS
  This is a multicenter retrospective study conducted in 14 Japanese ICUs in 12 centers. All patients older than 18 years and treated with CRRT due to AKI were eligible. We evaluated the effect of CRRT intensity by two different definitions: daily intensity (the mean intensity over each 24-h period) and average intensity (the mean of daily intensity during the period while CRRT was performed). To study the effect of different CRRT intensity on clearance of urea and creatinine, all patients/daily observations were arbitrarily allocated to one of 4 groups based on the average intensity and daily intensity: <10, 10-15, 15-20, and >20 mL/kg/h.
  
  
  RESULTS
  Total 316 patients were included and divided into the four groups according to average CRRT intensity. The groups comprised 64 (20.3%), 138 (43.7%), 68 (21.5%), and 46 patients (14.6%), respectively. Decreases in creatinine and urea increased as the average intensity increased over the first 7 days of CRRT. The relative changes of serum creatinine and urea levels remained close to 1 over the 7 days in the "<10" group. Total 1,101 daily observations were included and divided into the four groups according to daily CRRT intensity. The groups comprised 254 (23.1%), 470 (42.7%), 239 (21.7%), and 138 observations (12.5%), respectively. Creatinine and urea increased (negative daily change) only in the "<10" group and decreased with the increasing daily intensity in the other groups.
  
  
  CONCLUSIONS
  The lower limit of delivered intensity to control uremia during CRRT was approximately between 10 and 15 mL/kg/h in our cohort. A prescribed intensity of approximately 15 mL/kg/h might be adequate to control uremia for patients with severe AKI in the ICU. However, considering the limitations due to the retrospective nature of this study, prospective studies are required to confirm our findings.
authors: Hideto
authors: H
authors: Yasuda
authors: Shigehiko
authors: S
authors: Uchino
authors: Makiko
authors: M
authors: Uji
authors: Tetsu
authors: T
authors: Ohnuma
authors: Yoshitomo
authors: Y
authors: Namba
authors: Shinshu
authors: S
authors: Katayama
authors: Hiroo
authors: H
authors: Kawarazaki
authors: Noriyoshi
authors: N
authors: Toki
authors: Kenta
authors: K
authors: Takeda
authors: Junichi
authors: J
authors: Izawa
authors: Natsuko
authors: N
authors: Tokuhira
authors: Isao
authors: I
authors: Nagata
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017582:Renal Replacement Therapy / Q000379:methods* / Q000592:standards*; D012189:Retrospective Studies; D014508:Urea / Q000097:blood; D014511:Uremia / Q000097:blood / Q000175:diagnosis* / Q000628:therapy*
chemical_list: D015415:Biomarkers; D014508:Urea; D003404:Creatinine