Continuous Manual Exchange Transfusion for Patients with Sickle Cell Disease: An Efficient Method to Avoid Iron Overload

Summary

We have outlined a method of continuous manual exchange transfusion for the treatment of sickle cell disease in patients. This safe protocol was designed to effectively limit iron overload in patients in need of chronic transfusions and can be used extensively without any special equipment.

Abstract

Children with sickle cell anemia (SCA) may be at risk of cerebral vasculopathy and strokes, which can be prevented by chronic transfusion programs. Repeated transfusions of packed red blood cells (PRBCs) is currently the simplest and most used technique for chronic transfusion programs. However, iron overload is one of the major side effects of this therapy. More developed methods exist, notably the apheresis of RBC (erythrapheresis), which is currently the safest and most efficient method. However, it is costly, complicated, and cannot be implemented everywhere, nor is it suitable for all patients. Manual exchange transfusions combine one or more manual phlebotomies with a PRBC transfusion.

At the Reference Center of Sickle Cell Disease, we set up a continuous method of manual exchange transfusion that is feasible for all hospital settings, demands no specific equipment, and is widely applicable. In terms of HbS decrease, stroke prevention, and iron overload prevention, this method showed comparable efficiency to erythrapheresis. In cases where erythrapheresis is not available, this method can be a good alternative for patients and care centers.

Introduction

A single point mutation in the β-globin gene is responsible for the production of abnormal hemoglobin (hemoglobin S, HbS). This causes sickle cell anemia (SCA), one of the most common diseases worldwide¹. SCA patients' acute symptoms and some chronic complications can be treated by the transfusion of packed red blood cells (PRBCs). Indeed, the transfusion of normal RBCs corrects the anemia while diluting the sickle RBCs. As a result, it can increase the oxygen transport capacity while decreasing hemolysis and vaso-occlusive events. To avoid chronic complications or to treat patients with acute complications, transfusion combined with t....

Protocol

The protocol follows the guidelines of the hospital ethics committee. There are 3 steps in the exchange sessions: patient preparation; initial isovolemic phlebotomy (if appropriate); and whole-blood exchange, consisting of several cycles, or continuous whole-blood phlebotomy, which is associated with the infusion of diluted PRBCs. Depending of the Hb level of the patient, a fourth step of intermediary isovolemic phlebotomy can be added midway through the exchange stage. At the start of the session, all of the necessary material (packed RBCs and 5% serum albumin) must be ready. Also, each step must be prepared in advance. Other than a precision scale and double venous ....

Results

Here, we will compare the safety, cost, and efficiency of the MET method with erythrapheresis⁶, which is the most effective method to decrease the percentage of HbS in SCD patients. To do so, we recorded 1,353 transfusion exchange sessions in the Reference Center of SCD, including 333 sessions of AET and 1,020 sessions of MET, all in SCD children suffering from cerebral vasculopathy and/or strokes. For patients, we chose MET in children with a body weight under 25 .......

Discussion

The risk associated with this procedure is an unexpected misbalance between the phlebotomy and the transfusion, which can have dangerous consequences. A rapid depletion will lead to hypovolemia and acute anemia, while an excess transfusion without bleeding will lead to a dangerous increase in blood viscosity. In both cases, SCA patients could suffer from vaso-occlusive complications, as well as strokes. For this reason, one nurse must be dedicated to each patient and stay at his bedside during the whole procedure. There .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Precision scale
Cannula (x2)	Macopharma
Transfusion tubing (x2)	Macopharma
Bleeding bag (x4)	Macopharma
3 Way tap
Syringe (x4)
Hemoglobin test	HemoCue	Hb 201+ System