Erythrocytapheresis in Sickle Cell Disease and Multi-Organ Failure in the Intensive Care Unit.
Authors: Farhan Shatha Y. , Lopez_Plaza Ileana 
Published: October 2019

Abstract
Abstract 4627

Introduction
Patients with sickle cell disease (SCD), including those with homozygosity for hemoglobin (Hb) S (SCD-SS) or compound heterzygosity for sickle and Hb C (SCD-SC), suffer from chronic variable intravascular hemolysis, microvascular ischemia and organ damage. Vaso-occlusion results from a dynamic combination of abnormalities in hemoglobin S structure and function, red blood cell membrane integrity, erythrocyte density, endothelial activation, microvascular tone, inflammatory mediators, and coagulation. HbC enhances, by dehydrating the SC red cell, the pathogenic properties of HbS, resulting in a clinically significant disorder, but somewhat milder sickle cell anemia. The management of SCD continues to be supportive and includes hydration, pain relief, blood transfusion and psychosocial support. However, transfused red cells will significantly increase blood viscosity, potentially reducing blood flow, if the Hb level rises above 10 g/dL. Therefore, if the goal is an acute reduction in the proportion of sickled red cells in addition to an increase in oxygen-carrying capacity, exchange transfusion is the therapy of choice. We report 3 cases of (SCD-SS) and (SCD-SC) disease with multi-organ failure syndrome who were admitted to our intensive care unit (ICU) between January and July 09 where Erythrocyatperesis was effective but somewhat delayed.

Report
The first patient is a 46-year old male with SCD-SC disease who presented with severe leg, back, and chest pain. He was treated with intravenous fluid and nasal oxygen supplementation. Chest pain was sustained with severe hypoxemia, elevated troponins and somnolence developed third day of hospitalization. Fourth day he became more lethargic, breathing at 35/ min. His labs showed acute liver and kidney injury. The patient was transferred to ICU. In spite of respiratory and medical support, his medical status worsened, so hematology team was consulted and red cell exchange transfusion was made with subsequent improvement in mental status. The second patient was a 45 year old patient with SCD-SC disease who was found at home confused, complaining of back, chest and extremities pain, with unsteady gait and labored breathing. In Emergency Department (ED) he was hypotensive with abdominal tenderness and hypoactive bowel movements. His labs showed acute hepatic and renal injury with severe metabolic acidosis. Patient was resuscitated with IV fluids and intubated. CT scan of the abdomen showed diffuse bowel inflammation. On the third day of admission, hematology team was consulted and Erythrocytapheresis was started. His mental status improved slowly but he continued to have a seizure disorder and had to be on hemodialysis. The third patient is a 46 year old with SCD-SS disease and chronic lower extremity ulcers who had recurrent admissions for hyperpigmented gallstones and endoscopic retrograde cholangiopancreatography with stent placements. He presented to ED with nausea, vomiting, diarrhea and fever for 3 days. He was found hypotensive, tachycardic, with respiratory distress and acute liver and kidney abnormalities on labs. He was intubated and started on fluids and antibiotics. Thirty hours post admission he underwent erythrocytapheresis.

Conclusion
Red cell exchange transfusions remain an effective but possibly underutilized and delayed therapy in acute sickle cell complications, especially acute chest and the multi-organ failure syndromes. It can provide needed oxygen carrying capacity while reducing the overall viscosity of the blood. Although the need for a central line and the requirement for sickle- negative, as-fresh-as-possible blood, matched for minor antigens are major reasons for delay, it seems that it is mostly delayed for clinical reasons, trying to rule out other disorders or contributing factors and when the apheresis starts the patients are in the hospital/ICU for days already. We conclude that in patients with sickle cell disorder (SS or SC) being hypoxic and with chest or multi-organ failure syndrome, red cell exchange transfusion is effective treatment modality and should be initiated as soon as possible.

Disclosures:
No relevant conflicts of interest to declare.