Near Infrared Spectroscopy (NIRS) as Transfusion Indicator in Neurocritical Patients

Phase II Study of Usefulness of Near Infrared Spectroscopy to Optimize Red Blood Cells Transfusion in Neuro Critical Ill Patients With Severe Traumatic Brain Injury, Subarachnoid Hemorrhage or Intracerebral Hemorrhage.

Neurocritical ill patients are frequently transfused. Red blood cell transfusion (RBCT) in these patients has been associated with deleterious effects, including higher rates of nosocomial infections, multi-organ failure, and mortality. Therefore, it seems crucial to avoid any unnecessary RBCT. Most critically ill patients tolerate hemoglobin levels near 7 g/dL without an increase in morbidity or mortality rates. In this regard, a recent sub-analysis of TRICC trial has showed that TBI patients may tolerate hemoglobin levels as low as 7 g/dL, but other studies including neurocritical patients suggested that severe anemia may worsen clinical outcome. Therefore, optimal hemoglobin levels in neurocritical care patients remain largely unknown. Some textbooks and guidelines recommend to transfuse these patients to reach hemoglobin levels near to 10 g/dL, despite the lack of a solid scientific background supporting this target. Even though it has not been demonstrated, hemoglobin-based RBCT prescription could result in over- or under-transfusion in neurocritical patients. Alternatively, it has been suggested that more physiological transfusion triggers, using direct signals coming from the brain, will progressively replace arbitrary hemoglobin-based transfusion triggers in the neurocritical patients [65]. At the neurocritical units, patients are often monitored by using non-invasive methods, such as near infrared spectroscopy which indirectly measures regional cerebral oxygen saturation (rSO2). Changes in rSO2 values have been shown to directly correlate with changes in erythrocyte mass, thus increasing with RBCT and decreasing with blood losses. Moreover, rSO2 values also show a good correlation with clinical outcome and other variables which are often monitored in TBI patients. The purpose of this study is to ascertain as to whether rSO2 levels are more efficacious than conventional hemoglobin levels in guiding RBCT in patients admitted to a neurocritical care unit.

Intervention: In the rSO2 - strategy group, patients will be transfused to attain a post-transfusion rSO2 values higher than 60%.

Intervention: In the hemoglobin - strategy group, patients will be transfused to reach post-transfusion hemoglobin levels between 8.5 g/dL and 10 g/dL.

Number of units of packed packed red blood cell transfused, over the period that the patient was included into the protocol

GOS measures the degree of disability associated with the brain injury Unfavorable GOS included the categories of: death. vegetative status. severe disability.

Inclusion Criteria: Severe traumatic brain injury (Glasgow coma scale < 9), subarachnoid hemorrhage (Hunt and Hess scale ≥ 3) or intracranial hemorrhage Moderate anemia. Hemoglobin levels > 7 g/dL and < 10 g/dL Hemodynamical stability (mean arterial pressure > 75 mm Hg) Respiratory stability (PaO2 / FiO2 ratio > 220) Expected length of ICU stay > 3 days Exclusion Criteria: Patient's relatives' refusal to patient's inclusion in the study Active bleeding Ongoing need for blood products Patients necessitating ongoing resuscitation End-stage in which death is imminent Antecedents of angina or myocardial infarction (poor cardiopulmonary reserve) Deficient signal of rSO2 impeding its proper valuation

Leal-Noval SR, Arellano-Orden V, Munoz-Gomez M, Cayuela A, Marin-Caballos A, Rincon-Ferrari MD, Garcia-Alfaro C, Amaya-Villar R, Casado-Mendez M, Dusseck R, Murillo-Cabezas F. Red Blood Cell Transfusion Guided by Near Infrared Spectroscopy in Neurocritically Ill Patients with Moderate or Severe Anemia: A Randomized, Controlled Trial. J Neurotrauma. 2017 Sep;34(17):2553-2559. doi: 10.1089/neu.2016.4794. Epub 2017 Jul 19.