The VASCOVID team publishes an article in Biomedical Optics Express, highlighted as an Editor’s pick, describing how, by combining both time-domain near-infrared spectroscopy (TD-NIRS) and diffuse correlation spectroscopy (DCS), they have been able to assess the hemoglobin and blood flow oscillations of skeletal muscle microvasculature.
The vascular endothelium is a thin layer of cells that lines the inner surface of blood vessels throughout the entire circulatory system, from the heart to the smallest capillaries. The endothelial cells play a crucial role in many biological functions, such as regulating the blood vessel tone or maintaining the blood flow inside the blood vessels. In several diseases, such as in patients with sepsis, where the immune system reacts extremely to an infection, the role of this endothelium can be altered. Knowing more about these endothelium alterations can provide valuable information to clinicians.
Overcoming the limitations
There are some non-invasive techniques currently being used to monitor the microvascular health of patients admitted to intensive care units. However, they have several limitations, such as the need for a trained expert to manipulate them or poor reproducibility. To overcome those limitations, the VASCOVID team used a hybrid device that combines time domain NIRS and diffuse correlation spectroscopy to monitor the hemoglobin and blood flow oscillations of the skeletal muscles. These oscillations are very low-frequency hemodynamic signals related to the muscle and nervous tissues, that can help us to better understand the endothelial functions.
In the article, researchers describe how they used both technologies to detect those oscillations in four groups of body muscles, during resting state – the palm of the hand, the sole of the foot, the neck and the forearm –. They measured the power of the oscillation signals in 14 healthy subjects, the blood flow index and several hemodynamic parameters – such as the oxygen saturation and the blood oxyhemoglobin levels- and then compared the results of a septic patient with alterations in the endothelial function.
The results show that both time domain NIRS and diffuse correlation spectroscopy are suitable technologies to detect the hemoglobin and blood flow oscillations of the skeletal muscles, constituting a promising tool to assess the endothelium’s blood flow dynamics of critically ill patients.
Read the article: https://opg.optica.org/BOE/abstract.cfm?uri=BOE-14-11-5994
