Red blood cell transfusion in patients with subarachnoid hemorrhage: a multidisciplinary North American survey
1 Departments of Critical Care Medicine and Clinical Neurosciences, Hotchkiss Brain Institute, Foothills Medical Center, University of Calgary, 1403 29th Street NW, Calgary, AB T2N 2T9, Canada
2 Department of Neurology and Neurological Surgery, Neurology/Neurosurgery Intensive Care Unit, Washington University School of Medicine, Campus Box 8111, 660 S. Euclid Avenue, St Louis, MO 63110, USA
3 Department of Neurology, Divisions of Vascular Neurology and Neurocritical Care, Baylor College of Medicine, 6501 Fannin Street, MS: NB320, Houston, TX 77030, USA
4 Department of Neurology, Feinberg School of Medicine, Northwestern University, 710 N. Lake Shore Drive, Chicago, IL 60611, USA
5 Division of Neurosurgery, Department of Surgery, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, ON M5B 1W8, Canada
6 Department of Neurosurgery, University of Pennsylvania, 235 S. 8th Street, Philadelphia, PA 19106, USA
Critical Care 2011, 15:R30 doi:10.1186/cc9977Published: 18 January 2011
Anemia is associated with poor outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH). It remains unclear whether this association can be modified with more aggressive use of red blood cell (RBC) transfusions. The degree to which restrictive thresholds have been adopted in neurocritical care patients remains unknown.
We performed a survey of North American academic neurointensivists, vascular neurosurgeons and multidisciplinary intensivists who regularly care for patients with SAH to determine hemoglobin (Hb) concentrations which commonly trigger a decision to initiate transfusion. We also assessed minimum and maximum acceptable Hb goals in the context of a clinical trial and how decision-making is influenced by advanced neurological monitoring, clinician characteristics and patient-specific factors.
The survey was sent to 531 clinicians, of whom 282 (53%) responded. In a hypothetical patient with high-grade SAH (WFNS 4), the mean Hb concentration at which clinicians administered RBCs was 8.19 g/dL (95% CI, 8.07 to 8.30 g/dL). Transfusion practices were comparatively more restrictive in patients with low-grade SAH (mean Hb 7.85 g/dL (95% CI, 7.73 to 7.97 g/dL)) (P < 0.0001) and more liberal in patients with delayed cerebral ischemia (DCI) (mean Hb 8.58 g/dL (95% CI, 8.45 to 8.72 g/dL)) (P < 0.0001). In each setting, there was a broad range of opinions. The majority of respondents expressed a willingness to study a restrictive threshold of ≤8 g/dL (92%) and a liberal goal of ≥10 g/dl (75%); in both cases, the preferred transfusion thresholds were significantly higher for patients with DCI (P < 0.0001). Neurosurgeons expressed higher minimum Hb goals than intensivists, especially for patients with high-grade SAH (β = 0.46, P = 0.003), and were more likely to administer two rather than one unit of RBCs (56% vs. 19%; P < 0.0001). Institutional use of transfusion protocols was associated with more restrictive practices. More senior clinicians preferred higher Hb goals in the context of a clinical trial. Respondents were more likely to transfuse patients with brain tissue oxygen tension values <15 mmHg and lactate-to-pyruvate ratios >40.
There is widespread variation in the use of RBC transfusions in SAH patients. Practices are heavily influenced by the specific dynamic clinical characteristics of patients and may be further modified by clinician specialty and seniority, the use of protocols and advanced neurological monitoring.