Anemia and Transfusion After Subarachnoid Hemorrhage

Abstract

Delayed cerebral ischemia after subarachnoid hemorrhage (SAH) may be affected by a number of factors, including cerebral blood flow and oxygen delivery. Anemia affects about half of patients with SAH and is associated with worse outcome. Anemia also may contribute to the development of or exacerbate delayed cerebral ischemia. This review was designed to examine the prevalence and impact of anemia in patients with SAH and to evaluate the effects of transfusion. A literature search was made to identify original research on anemia and transfusion in SAH patients. A total of 27 articles were identified that addressed the effects of red blood cell transfusion (RBCT) on brain physiology, anemia in SAH, and clinical management with RBCT or erythropoietin. Most studies provided retrospectively analyzed data of very low-quality according to the GRADE criteria. While RBCT can have beneficial effects on brain physiology, RBCT may be associated with medical complications, infection, vasospasm, and poor outcome after SAH. The effects may vary with disease severity or the presence of vasospasm, but it remains unclear whether RBCTs are a marker of disease severity or a cause of worse outcome. Erythropoietin data are limited. The literature review further suggests that the results of the Transfusion Requirements in Critical Care Trial and subsequent observational studies on RBCT in general critical care do not apply to SAH patients and that randomized trials to address the role of RBCT in SAH are required.

Delayed neurological deterioration after subarachnoid haemorrhage

“…138 The optimal haemoglobin concentration is unknown, and guidelines recommend that decisions should be made on a casebycase basis. 139 Some physicians administer blood transfusions when haemo globin levels are <7 g/dl in patients without DCI, or <10 g/dl in patients with DCI. As blood transfusion has been associated with worse outcome, prevention of anaemia (which would require a blood transfusion) is recommended.…”

Patient Phenotypes Associated With Outcomes After Aneurysmal Subarachnoid Hemorrhage

“…The final component significantly, albeit less strongly, associated with angiographic vasospasm and DIND and, 24 After SAH, more than half of patients develop anemia. 25 Previous studies have consistently linked anemia or large hemoglobin reductions to infarction, death, and dependency, [26][27][28] as well as delayed ischemia.…”

The Rheology of Subarachnoid Hemorrhage

“…14 Fifty percent of patients with subarachnoid hemorrhage will get anemia in the first three days. 15 Female sex, worse clinical grade, lower admission hemoglobin and surgery predict anemia. 15 Causes of anemia include phlebotomy, surgical bleeding, gastrointestinal bleeding, reduced erthryropoiesis, reduced red blood cell life span and fluid overload.…”

“…15 Female sex, worse clinical grade, lower admission hemoglobin and surgery predict anemia. 15 Causes of anemia include phlebotomy, surgical bleeding, gastrointestinal bleeding, reduced erthryropoiesis, reduced red blood cell life span and fluid overload. 16 With anemia the heart and brain are protected by compensatory mechanisms that increase cardiac output and oxygen extraction.…”