Optimal Manual Exchange Transfusion Protocol for Sickle Cell Disease: A Retrospective Comparison of Two Comprehensive Care Centers in the United Kingdom and Canada

Abstract

Chronic red blood cell (RBC) transfusion is employed for a wide range of sickle cell disease complications, ranging from primary and secondary stroke prophylaxis to prevention of painful vaso-occlusive episodes. Currently different methods are employed by centers for chronic transfusion that include simple, automated and partial manual RBC exchange transfusion. A retrospective cohort study of two different manual RBC exchange transfusion methods was conducted between two comprehensive care centers in Toronto, ON, Canada and London, United Kingdom in 19 and 21 sickle cell disease adults, respectively. London used a weight-based protocol, while Toronto used a unit-based method. Our results indicated that sickle cell disease patients utilizing a weight-based method are more often unable to achieve the prescribed Hb S (HBB: c.20A > T) target compared to the unit-based method (90.0 vs. 53.0% in the weight-based and unit-based methods, respectively, p = 0.0123). On multivariable logistic regression, none of the covariates examined was found to influence the ability to achieve the prescribed Hb S target after accounting for the exchange transfusion method. Mean interval of exchange sessions, session duration, total units of packed RBC, volume of blood used by body weight each year, the mean post exchange hematocrit [or packed cell volume (PCV)] and ferritin change were similar in both cohorts. In conclusion, the unit-based method was more effective at maintaining the prescribed Hb S target.

• Erythrocytapheresis
• manual exchange transfusion
• sickle cell disease
• transfusion

Declaration of interest

K.H.M.K.’s research fellowship was funded in part by the American Society of Hematology Alternative Training Pathway Grant and an unrestricted education grant from Novartis Canada and Apotex Canada, and receives honoraria from Alexion and Novartis Canada. R.W. receives unrestricted education grant from Novartis Canada and Apotex Canada. P.T., B.K. and H.S.M. have no potential conflict of interest to declare. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.