Optimizing Blood Transfusions with Noninvasive Diffuse Optics

A recent study published in Biophotonics Discovery investigated hybrid diffuse optics (DO), a near-infrared light-based technology for noninvasive monitoring of continuous changes in blood flow and oxygenation.

For critically ill patients with anemia—a condition characterized by insufficient healthy red blood cells for oxygen transport—red blood cell transfusions (RBCTs) are a standard intervention. While transfusions increase oxygen availability, they can also alter blood flow dynamics, potentially affecting critical organs such as the brain. This study examined whether hybrid DO could provide detailed monitoring of these effects.

Unlike conventional systemic monitoring methods, such as blood sampling, hybrid DO enables localized assessment of oxygen delivery and utilization in specific tissues. Researchers applied optical probes to the foreheads and muscles of critically ill patients undergoing RBCTs in an intensive care unit to collect continuous data before, during, and after transfusion.

Results indicated a significant increase in oxygen supply to both brain and muscle tissues post-transfusion, confirmed by higher levels of total hemoglobin and oxygenated hemoglobin. Oxygen extraction fractions decreased in both regions, suggesting improved tissue oxygenation.

While muscle blood flow increased following transfusion, cerebral blood flow remained stable, suggesting autoregulatory mechanisms maintained cerebral oxygen balance. No evidence of under-perfusion or over-perfusion was observed in the brain, indicating that RBCTs did not induce adverse hemodynamic effects under these monitoring conditions.

These findings demonstrate the potential of hybrid DO for optimizing transfusion management by providing real-time, tissue-specific hemodynamic data. This approach could assist clinicians in tailoring transfusion strategies, minimizing risks, and improving patient outcomes. For example, monitoring cerebral oxygenation could help ensure adequate oxygen delivery while mitigating risks associated with excessive cerebral blood flow.

Potential applications of hybrid DO include:

• Personalized transfusion strategies: Real-time monitoring could support individualized transfusion protocols.
• Improved clinical decision-making: Tissue-specific oxygenation data could inform timely medical interventions.
• Expanded use of noninvasive monitoring tools: Optical technologies could reduce reliance on invasive procedures, improving patient safety in critical care settings.

This technology may have applications beyond intensive care, including neurocritical care, surgery, neonatal medicine, and chronic disease management.

Journal Reference:

Tagliabue, S., et al. (2025) Hybrid diffuse optical appraisal of peripheral and cerebral changes in critically ill patients receiving red blood cell transfusion. Biophotonics Discovery. doi.org/10.1117/1.BIOS.2.1.015001