The CIRE Study (CItrate REcirculation Study)

Rationale:

AV port reversal (AVPR) has been demonstrated to increase recirculation in venous catheters used in ICU for CVVH. The effects of this frequently used manoeuvre have not been described in the setting of CVVH using regional citrate anticoagulation.

Objective:

The aim of this study is to determine the effects of AVPR on recirculation, clearance, post-filter ionized calcium and subsequently citrate dosing.

Study design and methods:

Open trial studying the effect of AVPR in patients undergoing citrate CVVH. After measurement in standard catheter configuration, AVPR is performed after which effects on catheter recirculation, clearance, citrate dosing and post-filter ionized calcium (iCa) are monitored.

Sample sites:

Arterial line, arterial (pre-filter) port, postfilter port (after postdilution and calcium compensation), effluent sample. All flow rates to be noted.

Study population:

Twelve patients admitted to intensive care, requiring continuous renal replacement therapy (CRRT) for AKI. Patients are preferably anuric and have achieved good metabolic control under CVVH before inclusion in the study.

Inclusion criteria

• Critically ill patients requiring CRRT for AKI (RIFLE criteria)
• Written informed consent from the patient or legal representative
• No AV port reversal had taken place before inclusion in the study
• Diuresis is minimal or the patient is anuric so that effects of changes in clearance as a consequence of diuresis are minimalized and do not influence study outcomes.
• The patient has undergone CVVH for a number of days, ensuring good metabolic control, so that possible short term loss of clearance as a consequence of AV port reversal has no detrimental effects.

Exclusion criteria

• pre-existing chronic renal insufficiency requiring dialysis
• chronic immunosuppression
• liver cirrhosis Child-Pugh C
• severe or shock-related hepatitis
• Pregnancy