Assessment of oxygen extraction rate changes following red blood cell transfusion in the intensive care unit: A prospective observational noninterventional study

Background The decision-making process for red blood cell transfusion (RBCT) in critically ill patients in the intensive care unit (ICU) remains primarily guided by hemoglobin-based thresholds. However, as a component of personalized medicine, innovative and individualized criteria should be developed to optimize RBCT decisions. This study aims to assess the impact of RBCTs on oxygenation parameters and patient outcomes, with a specific focus on the oxygen extraction ratio (O2ER). Study Design and Methods This prospective observational study included 77 critically ill patients receiving RBCTs according to ICU transfusion protocols. The primary hypothesis is that patients with an O2ER > 0.30 will benefit most from RBCTs. To investigate this, patients receiving RBCTs were divided into two groups: those with O2ER > 0.30 (RBCTs appropriate) and those with O2ER <= 0.30 (RBCTs appropriateness questionable). The two groups were compared in terms of primarily O2ER, other oxygenation parameters, and clinical outcomes. The primary outcome was the change in O2ER following RBCTs, while secondary outcomes encompassed other oxygenation parameter changes. Results The O2ER > 0.30 group showed significant improvement in O2ER (0.38 +/- 0.04 vs. 0.32 +/- 0.05; p < .001), whereas no such improvement was observed in the O2ER <= 0.30 group (0.26 +/- 0.03 vs. 0.28 +/- 0.05; p: .017). Additionally, the O2ER > 0.30 group exhibited improvements in central venous oxygen saturation (ScvO(2)) following RBCTs, which were not seen in the O2ER <= 0.30 group. Discussion Our study reveals promising insights into the impact of RBCTs on O2ER; however, these physiological changes did not result in significant clinical improvements. Hence, this study provides a rational basis for the feasibility of implementing a personalized strategy focused on physiological triggers for RBCTs.