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THE UTILITY OF DIALYSIS FLUID AUTOFLOW TECHNOLOGY TO REDUCE CONSUMPTION OF WATER, ACID CONCENTRATE AND BICARBONATE IN A HAEMODIALYSIS POPULATION

Carlisle G, Croft D, Stoves J Department of Renal Medicine, Bradford St Luke’s Hospital

INTRODUCTION:Climate change presents a global health threat. Provision of end stage renal failure services includingin-centrehaemodialysisaccounts for 2% of the overall NHS budget and produces a significant carbon footprint. Our previous practice has been to choose between the 500mL/min and 800 mL/min dialysis fluid flowrate settings for patients who are dialysed usinga Fresenius 5008 machine, depending on the prescribed blood flow rate. The Autoflowfacility automatically sets the dialysate flow rate at 1.5 times the blood flow rate, thus fora 400 mL/min blood flow rate a 600 mL/min dialysis fluid flow rateis setautomatically (this would previously have been set manually at 800 mL/min). In addition to reducing the consumption of water and acid concentrate, the use of Autoflow provides an opportunity to use smaller Bibags (650g bags in place of 900g bags) for some haemodialysis treatments.

METHODS: Haemodialysis unit staff were informed of the change in practice and shown how to activate the Autoflow facility. A minimum dialysis fluid flow rate of 500 mL/min was agreed for patients with blood flow rates of < 330 mL/min, noting a previous finding of reduced dialysis adequacy when usingAutoflowin patients with low prescribed blood flow rates.Patients who continued to require 900g Bibags (i.e. those who were prescribed a blood flow rate of 500mL/min anda dialysis treatment time in excess of 4 hours)were identified, and650g Bibags were used for all other dialysis prescriptions. The adequacy of haemodialysis treatment (measured by urea clearance) before and after switchover wascompared using a paired t-test.

RESULTS: Following the change in practice there was a 9% reduction in water and acid concentrate consumption (the latter supplied using a previously installed central acid delivery system),with projected annual savings of £2,884 (1,140 m3 of water)and £ 2,880 respectively. The use of smaller Bibagsfor most haemodialysis treatments provided additional savingsof £5,760, making a total annual cost saving of£11,524.The Centre for Sustainable Healthcare calculated an associated3,715kg CO2 equivalent reduction in greenhouse gas emissions. The use of Autoflowdid not have a significant adverse effect on dialysisadequacy.

CONCLUSION: This study has demonstrated that use of the dialysis fluid Autoflowfacility may reduce the environmental and financial costs of haemodialysis treatment without compromisingdialysis adequacy.