Continuous is not continuous: The incidence and impact of circuit "down-time" on uraemic control during continuous veno-venous haemofiltration

Shigehiko Uchino, Nigel Fealy, Ian Baldwin, Hiroshi Morimatsu, Rinaldo Bellomo

Research output: Contribution to journalArticlepeer-review

151 Citations (Scopus)


Objective: There is little information on the duration of time that patients spend off therapy (down-time) during continuous veno-venous haemofiltration (CVVH) and the effect of this treatment free time on azotaemic control. Design and setting: Prospective observational study in the ICU of tertiary hospital. Patients and participants: 48 critically ill patients treated with CVVH at 2 1/h of ultrafiltration. Interventions: Prospective collection of demographic and biochemical data. Measurements and results: Two hundred and sixty-six filters were observed. Start and end times were collected for each filter. Creatinine and urea were measured daily and percentage of reduction of these two solutes was calculated (%Δ creatinine and urea). The median period when CVVH was not applied to a patient (down-time) was 3 h per day. There was a significant inverse correlation between down-time and %Δ creatinine and urea over each 24-h time cycle. On average at least 16 h per day of CVVH was required to maintain creatinine and urea concentration for each 24-h cycle. Conclusions: "Continuous" therapy is not truly continuous. Down-time adversely affects azotaemic control. Physicians prescribing CRRT should be aware of the consequences of such down-time on the quality and quantity of renal replacement therapy delivered.

Original languageEnglish
Pages (from-to)575-578
Number of pages4
JournalIntensive Care Medicine
Issue number4
Publication statusPublished - Apr 1 2003
Externally publishedYes


  • Acute kidney failure
  • Critical illness
  • Haemofiltration
  • Renal replacement therapy

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine


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