Assessment of oxygen extraction rate changes following red blood cell transfusion in the intensive care unit: a protocol for a prospective observational non-interventional study

INTRODUCTION: Haemoglobin transfusion thresholds have been used in the intensive care unit (ICU) to guide red blood cell transfusion (RBCT) decisions. Recent research has also focused on physiological indicators of tissue oxygenation as trigger points for blood transfusion. This study aims to assess the oxygen extraction rate (O(2)ER) as a critical indicator of the oxygen delivery–consumption balance in tissues and investigate its potential as a reliable trigger for blood transfusion in ICU patients by analysing clinical outcomes. The utilisation of physiological indicators may expedite the decision-making process for RBCT in patients requiring immediate intervention, while simultaneously minimising the risks associated with unnecessary transfusions. METHODS AND ANALYSIS: This prospective, single-centre, observational cohort study will include 65 ICU patients undergoing RBCT. We will evaluate essential markers such as arterial oxygen content, central venous oxygen content, arteriovenous oxygen difference, O(2)ER and near-infrared spectroscopy before and 15 min after transfusion. The primary outcome is the percentage increase in O(2)ER between the two groups relative to the initial O(2)ER level. Secondary outcomes will assess complications and patient outcomes in relation to baseline O(2)ER. A 90-day comprehensive follow-up period will be implemented for all enrolled patients. ETHICS AND DISSEMINATION: This study has obtained ethics committee approval from the Izmir Katip Celebi University Non-Interventional Clinical Studies Institutional Review Board. Written informed consent will be obtained from all patients before their enrolment in the study. The findings will be disseminated through publication in peer-reviewed journals and presentation at national or international conferences. TRIAL REGISTRATION NUMBER: NCT05798130