Do transfusion requirements increase after the diagnosis of vasospasm in patients with aneurysmal subarachnoid haemorrhage?

Abstract Background: Many patients experience impaired cerebral oxygen delivery secondary to vasospasm and delayed cerebral ischemia following aneurysmal subarachnoid haemorrhage (SAH). Anaemia is common after SAH affecting up to 50% patients, which may decrease cerebral oxygen delivery and is associated with worse clinical outcomes. Transfusion of allogeneic red cells increases the oxygen content of the blood but it not consistently associated with improved physiologic markers of clinical outcomes. The threshold for transfusion is not clear in patients with SAH. A recent survey found that most physicians would alter their transfusion threshold in SAH patients who develop delayed ischemia. The objective of our study is to identify the predictors of transfusion and to determine if the diagnosis of delayed ischemia increases the transfusion rates in patients with aneurysmal subarachnoid haemorrhage. Materials and Methods: We retrospectively reviewed the charts of 100 consecutive patients with SAH who were admitted to ICU for mechanical ventilation, and collected demographic and clinical data. Data were analyzed for the association between clinical factors and transfusion the differences in transfusion between the patients with and without vasospasm. Statistical methods included the t-test, univariate analysis and multivariate analysis. Results: Data from 96 patients were included in the analysis. Incidence of anaemia haemoglobin (Hb) < 100 gm/l and vasospasm were 67% (64/96) and 39% (38/96) respectively. Of 64 patients with anaemia, 27 patients received transfusion, while 38 patients did not receive a transfusion. The transfusion rates were similar between those who had vasospasm and who did not. However, out of the 14 patients with vasospasm who received a transfusion, 11 patients had been transfused after experiencing vasospasm, while only 3 were transfused before. On multivariate analysis only female sex, starting Hb levels and lowest Hb levels were found to be predictors of transfusion. Presence or absence of vasospasm was not found to be a predictor. Conclusions: From our retrospective review, we conclude that the incidence of anaemia is higher in patients with vasospasm. Sex and starting and lowest Hb levels were the only predictors of transfusion likelihood in aneurysmal subarachnoid haemorrhage while presence of vasospasm was not.