Investigation of spatial resolution dependent variability in transcutaneous oxygen saturation using point spectroscopy system

Abstract

Abstract. This paper aims to investigate the variation in one's percent mean transcutaneous oxygen saturation (StO2) with differences in spatial resolution of data. This work required the knowledge of extinction coefficient of hemoglobin derivatives in the wavelength range of 520 -600 nm to solve for the StO2 value via an iterative fitting procedure. A pilot study was conducted on three healthy subjects with spectroscopic data collected from their right index finger at different arbitrarily selected distances. The StO2 value estimated by Extended Modified Lambert Beer (EMLB) model revealed a higher mean StO2 of 91.1 ± 1.3% at a proximity distance of 30 mm compared to 60.83 ± 2.8% at 200 mm. The results showed a high correlation between data spatial resolution and StO2 value, and revealed a decrease in StO2 value as the sampling distance increased. The preliminary findings from this study contribute to the knowledge of the appropriate distance range for consistent and high repeatability measurement of skin oxygenation.

Portable and Rapid <i>In Vivo</i> Imaging of Tissue Oxygenation Changes Induced by Skin Perfusion Pressure

“…It also must be noted that the small fluctuation patterns in the inset of Fig. 2 (mean SD = 2.5 %) and the magnitudes of the observed values agreed considerably well with the reports of [12][13][14][15] that attributed the fluctuations to the oscillations in microcirculation system oxygen supply and metabolic mechanism. It is also found that the differences in the mean StO2 values of volunteers in Fig.…”

Tissue Oxygen Level in Acute and Chronic Wound: A Comparison Study

“…The relationship between spatial separation and StO2 at five varying distances (i.e. 30 mm, 50 mm, 100 mm, 150 mm and 200 mm) was previously reported in [20]; the recorded results and the corresponding fitted linear line is shown in Figure 2. Based on the best fitted line in Figure 2, a normalization factor of 1.08 was calculated from the ratio of the value at 170 mm and 200 mm.…”

“…These different experimental arrangements were made based on the position of the wound and for the convenience of the patients. It was reported in Philimon et al [20] that changes in the separation of skin region-detection system yielded different StO2 values. Since this experiment involved processing the spatially dependent reflected intensity of the multispectral images, a calibration procedure was necessary to normalize the measured reflectance from both samples.…”

“…Huong et al [19] have recently demonstrated the most probable range of tissue oxygen levels in wounds that healed timely using multispectral imaging system that provide illumination across a visible wavelength range of 520 600  nm. This study aims to expand the previous study in [20] by investigating and comparing the distribution of StO2 levels in acute wounds of healthy subjects and chronic wounds of diabetic subjects. An improved use of multispectral imaging system is introduced in this study by employing an alternative shorter wavelength range of 530 570  nm to detect reflectance data from the wound surface.…”

Skin Tissue Oxygen Saturation Prediction: A Comparison Study of Artificial Intelligence Techniques

“…Since the system interrogates blood in dermal capillaries, arterioles and venules [14], the predicted value is often taken as the average of oxygen saturation within the cutaneous microenvironment, StO2. Previous works [15,16] from this laboratory found that the range of predictions is dependent on the system configuration and architecture, and the wavelengths used. Meanwhile the use of Artificial Intelligence (AI) techniques has received a great deal of attention in this arena of study over the past years due to its ability to learn by itself through a large set of data, events and statistics before making decision.…”