scholarly journals Tissue Oximeter with Selectable Measurement Depth Using Spatially Resolved Near-Infrared Spectroscopy

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5573
Author(s):  
Masatsugu Niwayama ◽  
Naoki Unno

Tissue oxygenation sensing at a few millimeters deep is useful for surgical and postoperative management. However, the measurement sensitivity at each depth and the proper sensor combination have not been clarified. Here, the measurement characteristics of oximetry by spatially resolved near-infrared spectroscopy were analyzed using Monte Carlo simulation and phantom experiment. From summing the sensitivities of each depth, it was quantitatively found that the measurement sensitivity curve had a peak, and the measurement depth can be adjusted by combining the two distances between the light source and the detector. Furthermore, the gastric tissue was 10–20% smaller in terms of measurement depth than the skin-subcutaneous tissue. A miniaturized oximeter was prototyped so that it could be used in combination with an endoscope or laparoscope. The optical probes consisted of light emitting diodes with wavelengths of 770 nm and 830 nm and photodetectors located 3 to 30 mm from the light source. Phantom experiments using the probes demonstrated the tendency of theoretical analysis. These results suggest the possibility of measuring tissue oxygen saturation with a selectable measurement depth. This selectable method will be useful for obtaining oxygenation information at a depth of 2–5 mm, which is difficult to measure using only laparoscopic surface imaging.

2020 ◽  
Vol 57 (6) ◽  
pp. 341-347
Author(s):  
Jaeyeon Chung ◽  
Sang-Hwan Ji ◽  
Young-Eun Jang ◽  
Eun-Hee Kim ◽  
Ji-Hyun Lee ◽  
...  

Near-infrared spectroscopy devices can measure peripheral tissue oxygen saturation (StO<sub>2</sub>). This study aims to compare StO<sub>2</sub> using INVOS® and different O3™ settings (O3<sup>25:75</sup> and O3<sup>30:70</sup>). Twenty adults were recruited. INVOS® and O3™ probes were placed simultaneously on 1 side of forearm. After baseline measurement, the vascular occlusion test was initiated. The baseline value, rate of deoxygenation and reoxygenation, minimum and peak StO<sub>2</sub>, and time from cuff release to peak value were measured. The parameters were compared using ANOVA and Kruskal-Wallis tests. Bonferroni’s correction and Mann-Whitney pairwise comparison were used for post hoc analysis. The agreement between StO<sub>2</sub> of devices was evaluated using Bland-Altman plots. INVOS® baseline value was higher (79.7 ± 6.4%) than that of O3<sup>25:75</sup> and O3<sup>30:70</sup> (62.4 ± 6.0% and 63.7 ± 5.5%, respectively, <i>p</i> &#x3c; 0.001). The deoxygenation rate was higher with INVOS® (10.6 ± 2.1%/min) than with O3<sup>25:75</sup> and O3<sup>30:70</sup> (8.4 ± 2.2%/min, <i>p</i> = 0.006 and 7.5 ± 2.1%/min, <i>p</i> &#x3c; 0.001). The minimum and peak StO<sub>2</sub> were higher with INVOS®. No significant difference in the reoxygenation rate was found between the devices and settings. The time to reach peak after cuff deflation was faster with INVOS® (both <i>p</i> &#x3c; 0.001). Other parameters were similar. There were no differences between the different O3™ settings. There were differences in StO<sub>2</sub> measurements between the devices, and these devices should not be interchanged. Differences were not observed between O3™ device settings.


Critical Care ◽  
2009 ◽  
Vol 13 (Suppl 1) ◽  
pp. P239
Author(s):  
R Kopp ◽  
S Rex ◽  
K Dommann ◽  
G Schälte ◽  
G Dohmen ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Leeann R. Pavlek ◽  
Clifford Mueller ◽  
Maria R. Jebbia ◽  
Matthew J. Kielt ◽  
Omid Fathi

With advances in neonatal care, survival of premature infants at the limits of viability has improved significantly. Despite these improvement in mortality, infants born at 22–24 weeks gestation are at a very high risk for short- and long-term morbidities associated with prematurity. Many of these diseases have been attributed to abnormalities of tissue oxygenation and perfusion. Near-infrared spectroscopy utilizes the unique absorption properties of oxyhemoglobin and deoxyhemoglobin to provide an assessment of regional tissue oxygen saturation, which can be used to calculate the fractional tissue oxygen extraction. This allows for a non-invasive way to monitor tissue oxygen consumption and enables targeted hemodynamic management. This mini-review provides a brief and complete overview of the background and physiology of near-infrared spectroscopy, practical use in extremely preterm infants, and potential applications in the neonatal intensive care unit. In this mini-review, we aim to summarize the three primary application sites for near-infrared spectroscopy, disease-specific indications, and available literature regarding use in extremely preterm infants.


2018 ◽  
Vol 53 (8) ◽  
pp. 782-787
Author(s):  
Babak Shadgan ◽  
Amir H. Pakravan ◽  
Alison Hoens ◽  
W. Darlene Reid

Context:  Contrast baths (CB) is a thermal treatment modality used in sports medicine, athletic training, and rehabilitation settings. Proposed physiological effects of CB include increasing tissue blood flow and oxygenation and decreasing tissue swelling and edema to promote better healing, improved limb function, and quicker recovery. Objective:  To investigate the physiological effects of CB on the intramuscular hemodynamics and oxygenation of the lower leg muscles using near-infrared spectroscopy (NIRS), an optical method for monitoring changes in tissue oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) as well as tissue oxygen saturation index (TSI%). Design:  Descriptive laboratory study. Patients or Other Participants:  Ten healthy men and women with a mean age of 29 (range = 17 ± 42) years, mean body mass index of 24.6 ± 3.2, and mean adipose tissue thickness of 6.4 ± 2.2 mm. Intervention(s):  Conventional CB (10-minute baseline, 4 : 1-minute hot : cold ratio) was applied to the left lower leg. Main Outcome Measure(s):  Changes in chromophore concentrations of O2Hb, HHb, tHb, and TSI% of the gastrocnemius muscle were monitored during 10 minutes of baseline measurement, a 30-minute CB protocol, and 10 minutes of recovery using a spatially resolved NIRS. Results:  After a 30-minute CB protocol, increases (P &lt; .05) in tissue O2Hb (7.4 ± 4 μM), tHb (7.6 ± 6.1 μM), and TSI% (3.1% ± 2.3%) were observed as compared with baseline measures. Conclusions:  Application of CB induced a transient change in the hemodynamics and oxygenation of the gastrocnemius muscle in healthy individuals. The effect of CB application in improving tissue hemodynamics and oxygenation may, therefore, support the therapeutic benefits of CB in the treatment of muscle injuries.


2016 ◽  
Vol 59 (2) ◽  
pp. 167-170 ◽  
Author(s):  
Takaaki Watanabe ◽  
Masato Ito ◽  
Fuyu Miyake ◽  
Ryo Ogawa ◽  
Masanori Tamura ◽  
...  

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