Introduction: We sought to explore the relationship between the systemic inflammatory response, anemia and clinical outcomes after aneurysmal subarachnoid hemorrhage.

Methods: We performed a retrospective analysis of 194 consecutive patients with aneurysmal subarachnoid hemorrhage. SIRS was characterized by two or more of the following criteria on any given day during the first week of hospitalization: (1) temperature >38°C or <36°C; (2) white blood cell count >12,000 or <4,000; (3) heart rate >90 beats per minute (tachycardia); (4) respiratory rate >20 breaths per minute (tachypnea). Anemia was defined as a hemoglobin level <10 g/dl. The minimum hemoglobin relative percentage (MHRP) was defined as the percentage of the patient’s minimum hemoglobin level during hospitalization relative to their baseline hemoglobin level on admission.

Results: 57% of patients had SIRS present on day of admission. Mean admission hemoglobin level was 13.17 (±1.95) g/dl (range: 8.4-19.1 g/dl). 67% of patients developed anemia during their hospital stay. Increased cumulative SIRS burden during the first week of hospitalization was associated with increased incidence of anemia and reduced MHRP (P<0.05). Age (OR 0.91, 95% OR 0.87-0.95), WFNS grade >/=4 (OR 0.21, 95% CI 0.08-0.56), modified Fisher score >/=3 (OR 0.28, 95% CI 0.08-0.95), cerebral infarct (OR 0.14, 95% CI 0.05-0.48), SIRS on admission (OR 0.28, 95% CI 0.12-0.66) and MHRP (OR 1.06, 95% CI 1.02-1.12) were independently associated with discharge to home. Increased MHRP was independently associated with a reduced odds of DND (OR 0.93, 95% CI 0.90-0.97), and refractory cerebral vasospasm requiring intra-arterial rescue therapy (OR 0.91, 95% CI 0.88-0.95) on multivariable regression.

Conclusions: Admission WFNS grade >/=4, admission hemoglobin, and SIRS burden during the first week of hospitalization were independently associated with the development of anemia. Decreases in hemoglobin during hospitalization, defined by the MHRP, were predictive of discharge disposition, the onset of DND, and the need for intra-arterial therapy.

Patient Care: This research may improve patient care by providing further insight into the potential mechanisms behind the development of anemia following aneurysmal subarachnoid hemorrhage. Additionally, we highlight the potential impact of changes in hemoglobin parameters on patient outcomes and shed light on the potential for improvement in transfusion practices in subarachnoid hemorrhage patients who become critically ill.

Learning Objectives: The purpose of this exploratory analysis is to further investigate the relationship between SIRS and anemia following aneurysmal subarachnoid hemorrhage. Secondly, we investigate the relationship between SIRS, hemoglobin parameters, and various outcome measures, such as delayed neurologic deficit (DND), cerebral vasospasm, refractory vasospasm requiring intra-arterial rescue therapy, cerebral infarct, and discharge disposition.

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