Emergency red cell exchange for the management of acute complications in sickle cell disease: Automated versus manual.

BACKGROUND: Red blood cell exchange is the cornerstone of the management for acute complications of sickle cell disease. It improves anaemia and improvesperipheral tissue oxygen delivery while at the same time reduces the proportion of circulating sickle erythrocytes. Even though automated red cell exchange is very effective in rapidly lowering the Hb S level, 24-h availability is currently not feasible for most specialist centres including our own. OBJECTIVE: Here, we describe our experience using both automated and manual red cell exchange for the management of acute sickle cell complications. METHODS: Eighty-six such episodes have been recorded between June 2011 and June 2022 comprising of 68 episodes of automated and 18 episodes of manual red cell exchange. RESULTS: The post procedure Hb S/S + C level was 18% after automated and 36% after manual red cell exchange. The platelet count dropped by 41% and 21% after automated and manual red cell exchange respectively. The clinical outcomes including need for organ support, duration of stay in the intensive care unit and overall length of hospitalisation was comparable between the two groups. CONCLUSION: In our experience, manual red cell exchange is a safe and effective alternative to an automated procedure that can be used while specialist centres are building up their capacity to offer automated red cell exchange for all patients requiring the intervention.

Therapeutic plasma exchange in the management of acute complications of sickle cell disease: A single centre experience.

Sickle cell disease results in systemic inflammation even at steady state and this is accentuated during acute crises. The plasma of affected patients contains several proinflammatory cytokines as well as adhesion molecules and prothrombotic factors. This environment promotes further red cell sickling while many of these substances can cause direct tissue toxicity and end-organ damage. Even though red cell transfusion, whether simple or exchange, is the mainstay of treatment of severe acute complications, addition of therapeutic plasma exchange could potentially provide additional benefit by removing such harmful substances. Here, we describe two cases where therapeutic plasma exchange was used. The first involved a patient with the acute chest syndrome who despite adequate red cell exchange remained significantly hypoxic and in severe pain. We therefore proceeded to perform plasma exchange; this led to rapid clinical improvement and resolution of his symptoms. The second case involved a patient with intractable chest wall pain and impending acute chest syndrome; this patient also had a past history of hyperhaemolysis. The patient underwent therapeutic plasma exchange with very rapid resolution of the pain, avoidance of any respiratory deterioration and full recovery. We also give a brief summary of our previous experience using plasma exchange in patients with sickle cell disease. Plasma exchange was well tolerated with no adverse events in all cases we have treated, led to rapid resolution of pain irrespective of primary indication and in the majority of cases to a favourable clinical outcome.

Complete neurological recovery from fat embolism syndrome in sickle cell disease after sequential red cell exchange transfusion and therapeutic plasma exchange.

Fat embolism syndrome in sickle cell disease is associated with great mortality, while more than half of survivors suffer severe neurological sequelae. Release of fat droplets leads to obstruction of the microcirculation as well as generation of proinflammatory cytokines that can cause direct tissue injury. Red cell exchange transfusion can be life-saving but the addition of therapeutic plasma exchange may further improve outcomes by removing such inflammatory mediators. Here, we describe the case of a 27-year-old male patient with sickle cell anaemia presenting with typical features of fat embolism syndrome including neurological involvement with greatly reduced level of consciousness. MRI of his brain showed multiple widespread microhemorrhages giving the characteristic "star field" pattern but also a cytotoxic lesion of the corpus callosum, known to be the result of direct neurotoxicity by proinflammatory cytokines. The patient underwent emergency red cell exchange transfusion leading only to modest clinical improvement but fully regained consciousness after three cycles of therapeutic plasma exchange. This case highlights the deleterious effect of the hyperinflammatory state characteristic of many sickle cell complications and supports further exploring the potential benefit from plasma exchange as an adjunct to red cell exchange in order to remove proinflammatory cytokines during acute complications of sickle cell disease.

Automated Red Cell Exchange in the Management of Sickle Cell Disease.

Red cell transfusion represents one of the cornerstones of the chronic management of sickle cell disease, as well as its acute complications. Automated red cell exchange can rapidly lower the number of circulating sickle erythrocytes, without causing iron overload. Here, we describe our experience, having offered this intervention since 2011. A transient reduction in the platelet count by 61% was observed after the procedure. This was not associated with any haemorrhagic complications. Despite exposure to large volumes of blood, the alloimmunisation rate was only 0.027/100 units of red cells. The absence of any iron loading was confirmed by serial Ferriscans, performed over a number of years. However, patients with advanced chronic kidney disease showed evidence of iron loading due to reduced innate haemopoiesis and were subsequently switched to simple transfusions. A total of 59% of patients were on regular automated red cell exchange with a history of recurrent painful crises. A total of 77% responded clinically, as evidenced by at least a 25% reduction in their emergency hospital attendance for pain management. The clinical response was gradual and increased the longer patients stayed on the program. The earliest sign of clinical response was a reduction in the length of stay when these patients were hospitalised, indicating that a reduction in the severity of crises precedes the reduction in their frequency. Automated red cell exchange also appeared to be beneficial for patients with recurrent leg ulcers and severe, drug resistant stuttering priapism, while patients with pulmonary hypertension showed a dramatic improvement in their symptoms as well as echocardiographic parameters.