Efficacy and safety of a membrane based regional citrate anticoagulation plasma exchange protocol: an observational, prospective, single center study

Aim: To investigate the efficacy and safety of a membrane based regional citrate anticoagulation plasma exchange protocol Background: Therapeutic plasma exchange is used in the treatment of some neurological, immunological, and haematological diseases. Citrate-based anticoagulation is often used for batched, centrifugal apheresis systems but heparin appears to be more common when continuous, membrane based systems are used. Citrate has an advantage in membrane based systems when heparin is contra-indicated but there is little published data to guide dosing. Methods: In this observational, prospective, single center study, plasma exchange sessions were performed using a pre-filter citrate infusion and no systemic anticoagulation. Systemic plasma ionized calcium was measured prior to commencement, 30 minutes after commencing and then hourly during the plasma exchange procedure. Calcium was infused post filter and adjusted based on systemic plasma ionized calcium concentrations. Safety and efficacy were assessed by extraction of clinical events contemporaneously recorded in the electronic health record and by laboratory results for systemic ionized calcium, bicarbonate, and magnesium. Data analysis was by t-test or Wilcoxon sign rank test as appropriate Results: Thirty-six sessions of citrate anticoagulated plasma exchange were performed in 5 patients. Two filters clotted, no patient experienced symptomatic hypocalcaemia and the lowest recorded ionized calcium during treatment was 0.85mmol/L. The mean pre and post procedure systemic ionized calcium were 1.070.07 and 1.020.10 mmol/L respectively (P=0.03). Conclusions: Protocol driven membrane based regional citrate anticoagulated plasma exchange can be performed safely and effectively.