Red Blood Cell Transfusion Guided by Near Infrared Spectroscopy in Neurocritically Ill Patients with Moderate or Severe Anemia: A Randomized, Controlled Trial

Abstract

In neurocritically ill patients (NCPs), the use of hemoglobin level as the sole indicator for red blood cell transfusion (RBCT) can result in under- or over-transfusion. This randomized controlled trial was conducted to ascertain whether a transcranial oxygen saturation (rSO) threshold, as measured by near-infrared spectroscopy, reduces RBCT requirements in anemic NCPs (closed traumatic brain injury, subarachnoid, or intracerebral hemorrhage), compared with a hemoglobin threshold alone. Patients with hemoglobin 70-100 g/L received RBCTs to attain an rSO > 60% (rSO arm) or to maintain hemoglobin between 85 and 100 g/L (hemoglobin arm). A total of 102 NCPs (51 in each group) were included in the intention-to-treat analysis, and 97 were included in the per-protocol analysis (51 and 46, respectively). Compared with those from the hemoglobin arm, patients in rSO arm received fewer RBC units (1.0 ± 0.1 vs. 1.5 ± 1.4 units/patient; p < 0.05) and showed lower hemoglobin levels while in protocol. There were no differences between the study arms regarding the percentage of transfused patents (59% vs. 71%; relative risk 0.83 [95% CI 0.62-1.11]), stay on neurocritical care unit (21 vs. 20 days), unfavorable Glasgow Outcome Scale scores on hospital discharge (57% vs. 71%), in-hospital mortality (6% vs. 10%), or 1 year mortality (24% vs. 24%). Among NCPs with hemoglobin concentrations of 70-85 g/L, withholding transfusion until rSO is <60% may result in reduced RBCs requirements compared with routinely transfusing to attain a hemoglobin level >85 g/L. Further studies are required to confirm this finding and its possible impact on clinically significant outcomes.

Anemia prevalence and incidence and red blood cell transfusion practices in aneurysmal subarachnoid hemorrhage: results of a multicenter cohort study

“…Only one small trial ( N = 44) has compared two transfusion targets (100 g/L and 115 g/L) in aSAH, but it was underpowered to examine clinically important outcomes [ 7 ]. Another small mixed brain injury population trial ( N = 102) compared a hemoglobin (Hb) target with a transcranial oxygenation target, but it, too, was underpowered to examine clinically important outcomes [ 8 ]. Despite this absence of evidence, current aSAH management guidelines recommend considering RBC transfusion in anemic patients at risk for cerebral ischemia, but they do not suggest specific transfusion thresholds to guide clinicians [ 1 , 3 ].…”

Regional cerebral tissue oxygen saturation changes following blood transfusion in neuro‐intensive care unit patients – a pilot observational study

“…The conventional cut-off value for rSO 2 to detect hypoxia is around 60%. In a recent randomised controlled trial in neuro-ICU patients, an rSO 2 value of less than 60% was used to determine RBC transfusion, and less transfusion requirement was noted in this group compared to the haemoglobin-targeted group (Leal-Noval et al, 2017). However, the patient outcomes did not differ between the two groups.…”

Red Blood Cell Transfusion Practices in the Neurointensive Care Unit: A Narrative Review

“…Studies have shown improvement in cerebral oxygenation and metabolic parameters following RBCT, though not the neurologic outcome. [24][25][26][27]…”

“…48 In a randomized controlled trial conducted on NICU patients, RBCT requirements reduced when RBCT was guided by rSO 2 (< 60%) as against Hb-guided, though the overall outcomes remained the same. 27 Changes in brain tissue oxygenation (PbtO 2 ) were studied following RBCT in TBI patients. 23,24 It was shown that Hb levels < 9 g/dL were associated with PbtO 2 < 20 mm Hg and an unfavorable outcome.…”