In Vivo Transcutaneous Monitoring of Hemoglobin Derivatives Using a Red-Green-Blue Camera-Based Spectral Imaging...

Area of Science:

• Biomedical optics
• Physiological monitoring
• Medical imaging

Background:

• Cyanosis, a bluish skin discoloration, indicates potential underlying medical conditions affecting oxygenation.
• Monitoring hemoglobin oxygenation is crucial for managing ischemic injury.
• Methemoglobinemia can cause cyanosis and alter tissue oxygen levels.

Purpose of the Study:

• To confirm the feasibility of a red-green-blue camera-based spectral imaging method for simultaneous quantification of methemoglobin, oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue oxygen saturation.
• To evaluate the method's ability to monitor changes in skin hemodynamics and tissue viability.

Main Methods:

• Developed and applied a spectral imaging method using an RGB camera to estimate spectral diffuse reflectance.
• Utilized Wiener estimation and multiple regression analysis based on Monte Carlo simulations.
• Performed in vivo experiments on rat dorsal skin, inducing methemoglobinemia with sodium nitrite and varying inspired oxygen levels (normoxia, hypoxia, anoxia).

Main Results:

• The method successfully quantified methemoglobin concentration (CmetHb), oxygenated hemoglobin (CHbO), deoxygenated hemoglobin (CHbR), total hemoglobin (CHbT), and tissue oxygen saturation (StO2).
• Induced methemoglobinemia showed a rapid increase in CmetHb and a significant drop in StO2.
• Changes in CHbT and StO2 correlated with physiological responses to varying fractions of inspired oxygen (FiO2).

Conclusions:

• The spectral imaging method is feasible for simultaneous monitoring of key hemoglobin parameters and tissue oxygen saturation.
• This technique holds potential for evaluating skin hemodynamic changes indicative of compromised tissue viability.
• The findings support the use of this method for early detection and management of conditions leading to cyanosis and ischemia.