Blood transfusion and filter set requirements with citrate anticoagulation compared with heparin in renal replacement therapy

As an intensive care unit, we have switched from using systemic heparinisation to using citrate regional anticoagulation for renal replacement therapy (RRT); our data add to the growing evidence of its benefit, which we feel may be of use to other units.

Citrate is the recommended anticoagulant for continuous RRT ¹ and is thought to confer numerous benefits. ² We performed a clinical effectiveness observational study investigating blood transfusion requirements and haemofilter set life before and after the change at Royal Surrey County Hospital from systemic heparin to citrate regional anticoagulation. Our unit uses a transfusion trigger of 70 g/L³ unless the clinical situation dictates otherwise.

Our data were collected from electronic records covering a period of six months of heparin anticoagulation and a year of citrate regional anticoagulation. We collected data on set life and the number of blood transfusions patients received during the period of filtration, and in the 24-h period afterwards. Data on transfusion requirements were excluded if the transfusion was part of initial resuscitation or massive haemorrhage during the period of filtration.

Fifty patients received heparin and 100 patients received citrate anticoagulation totalling 11,638 h of filtration. The mean filter life increased from 8.1 h with heparin to 22.1 h with citrate. The number of transfusions required fell from 0.86 units per day with heparin to 0.54 units per day with citrate (p = 0.11 by Student’s t-test). There was no significant difference in the duration of RRT required between the two groups.

The cost savings from this result, in both reduced numbers of filtration sets used and transfusions required were calculated. The cost of a single filter set is £80, representing a cost saving of £35,000 per year. A unit of packed red cells costs approximately £120; the reduction in transfusion requirements represents a cost saving of £6400 per year. We believe that citrate anticoagulation offers significant benefits in line with previously published evidence.