Intraoperative transfusion threshold and tissue oxygenation: a randomised trial

Area of Science:

• Anesthesiology
• Transfusion Medicine
• Surgical Critical Care

Background:

• Maintaining adequate oxygen delivery is crucial during major surgery.
• The optimal hemoglobin (Hb) concentration threshold for red blood cell (RBC) transfusion remains debated.
• Subcutaneous oxygen tension is a potential indicator of tissue oxygenation.

Purpose of the Study:

• To investigate if a higher Hb concentration threshold (8.9 g/dL) improves subcutaneous oxygen tension during major spinal surgery compared to a restrictive threshold (7.3 g/dL).
• To assess the association between Hb levels and tissue oxygenation in patients undergoing spinal fusion.

Main Methods:

• A randomized controlled trial involving 50 patients undergoing spinal fusion with instrumentation.
• Patients were assigned to either a restrictive (Hb 7.3 g/dL) or liberal (Hb 8.9 g/dL) RBC transfusion group.
• Subcutaneous oxygen tension was measured using a polarographic electrode.

Main Results:

• No significant difference in the median change or lowest subcutaneous oxygen tension was observed between the restrictive and liberal transfusion groups.
• The P-values for the primary endpoint and lowest oxygen tension were 0.78 and 0.85, respectively.
• Forty-eight patients completed the intention-to-treat analysis.

Conclusions:

• A liberal Hb transfusion threshold of 8.9 g/dL was not associated with improved subcutaneous oxygen tension compared to a restrictive threshold of 7.3 g/dL in major spinal surgery.
• The study was limited by methodological difficulties, impacting the certainty of the findings.
• Further research is needed to establish optimal transfusion strategies for tissue oxygenation during complex surgeries.