Postoperative Transfusion Guidelines in Aneurysmal Cerebral Subarachnoid Hemorrhage: A Systematic Review and Critical Summary of Available Evidence

Objective: Surgical management of aneurysmal subarachnoid hemorrhage (SAH) often involves red blood cell (RBC) transfusion, which increases the risk of postoperative complications. RBC transfusion guidelines report on chronically critically ill patients and may not apply to patients with SAH. Our study aims to synthesize the evidence to recommend RBC transfusion thresholds among adult patients with SAH undergoing surgery. Methods: A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to critically assess primary articles discussing RBC transfusion thresholds and describe complications secondary to RBC transfusion in adult patients with SAH in the perioperative period. Results: Sixteen articles meeting our search strategy were reviewed. Patients with SAH who received blood transfusion were older, female, had World Federation of Neurosurgical Societies grade IV–V and modified Fisher grade 3–4 scores, and presented with more comorbidities such as hypertension, diabetes, and cardiovascular and pulmonary diseases. In addition, transfusion was associated with multiple postoperative complications, including higher rates of vasospasms, surgical site infections, cardiovascular and respiratory complications, increased postoperative length of stay, and 30-day mortality. Analysis of transfused patients showed that a higher hemoglobin (>10 g/dL) goal after SAH was safe and that patients may benefit from a higher whole hospital stay hemoglobin nadir, as shown by a reduction in risk of cerebral vasospasm and improvement in clinical outcomes (level B class II). Conclusions: Among patients with SAH, the benefits of reducing cerebral ischemia and anemia are shown to outweigh the risks of transfusion-related complications.