Enhancing Blood Transfusions Using Noninvasive Diffuse Optics

Reviewed by Lexie Corner   February 3, 2025

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

For critically ill patients with anemia—a condition characterized by a lack of healthy red blood cells to transport oxygen—red blood cell transfusions (RBCT) are a standard intervention. While blood transfusions increase oxygen availability, they can also alter blood flow dynamics, which can affect vital organs such as the brain. This study investigated whether combined DO could provide accurate monitoring of these effects.

Unlike conventional systemic monitoring methods such as blood sampling, hybrid DO allows for localized assessment of oxygen delivery and utilization in specific tissues. The researchers used optical probes on the forehead and muscles of critically ill patients undergoing RBCT in the intensive care unit to collect continuous data before, during, and after blood transfusion.

The results showed a significant increase in oxygen delivery to brain and muscle tissues after blood transfusion, as confirmed by higher levels of total hemoglobin and oxygenated hemoglobin. The oxygen extraction fraction decreased in both regions, indicating improved tissue oxygenation.

While muscle blood flow increased after injection, cerebral blood flow remained constant, suggesting that autoregulatory mechanisms maintain cerebral oxygen balance. No signs of perfusion or hyperperfusion were observed in the brain, suggesting that RBCTs do not produce adverse hemodynamic effects under these monitoring conditions.

These findings demonstrate the potential of hybrid DO to optimize transfusion management by providing tissue-specific hemodynamic data in real time. This approach may help clinicians adjust transfusion strategies, minimize risks, and improve patient outcomes. For example, cerebral oxygenation monitoring may help ensure adequate oxygenation while reducing the risks associated with excessive cerebral blood flow.

Potential applications of hybrid DO include:

• Personalized transfusion strategies:  Real-time monitoring can support individualized transfusion protocols. 
• Improving clinical decision-making:  Tissue oxygenation data can indicate timely medical interventions. 
• Widespread use of non-invasive monitoring tools:  Optical technologies can reduce reliance on invasive procedures and improve patient safety in critical care settings. 

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