Evaluating the dynamics of brain tissue oxygenation using near-infrared spectroscopy on various experimental models

2019 ◽  
Vol 16 (11) ◽  
pp. 115602
Author(s):  
D M Kustov ◽  
A S Sharova ◽  
V I Makarov ◽  
A V Borodkin ◽  
T A Saveleva ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Brain Tissue ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Experimental Models ◽  
Brain Tissue Oxygenation

Measurement of Peripheral Venous Oxygen Saturation in the Leg Using Near-Infrared Spectroscopy

1997 ◽  
Vol 12 (3) ◽  
pp. 96-99 ◽  
Author(s):  
D. Wertheim ◽  
R. Salaman ◽  
J. Melhuish ◽  
R. Williams ◽  
I. Lane ◽  
...  
Keyword(s):  
Near Infrared ◽  
Tissue Oxygenation ◽  
Venous Occlusion ◽  
Lower Leg ◽  
Non Invasive ◽  
Short Period ◽  
Venous Oxygen Saturation ◽  
Invasive Method ◽  
Healing Of Wounds ◽  
Total Haemoglobin

Background: It has been suggested that poor healing of wounds may be associated with reduced tissue oxygenation. A non-invasive method of assessing peripheral venous oxygenation has been investigated. Method: Changes in oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb), oxidized cytochrome aa3 (cyt aa3) and total haemoglobin (tHb) were monitored in the left lower leg of seven healthy volunteers. A short period of venous occlusion was achieved by rapidly inflating a sphygmomanometer cuff placed around the leg to 60 mmHg. The changes in O2Hb and tHb, with respect to the baseline readings, were evaluated. PSvO2 was calculated from (ΔO2Hb/ΔtHb) × 100%. Results: From 17 sets of readings on the seven volunteers the median PSvO2 calculated was 64% (range 50–86%). Conclusion: This method appears to be a simple means of evaluating PSvO2. A change in cyt aa3 was often seen associated with the venous occlusion.

scholarly journals Increased tissue oxygenation explains the attenuation of hyperemia upon repetitive pneumatic compression of the lower leg

2017 ◽  
Vol 123 (6) ◽  
pp. 1451-1460 ◽  
Author(s):  
Alessandro Messere ◽  
Gianluca Ceravolo ◽  
Walter Franco ◽  
Daniela Maffiodo ◽  
Carlo Ferraresi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Femoral Vein ◽  
Lower Leg ◽  
Local Circulation ◽  
Doppler Measurement ◽  
Key Factor ◽  
Interstimulus Intervals

The rapid hyperemia evoked by muscle compression is short lived and was recently shown to undergo a rapid decrease even in spite of continuing mechanical stimulation. The present study aims at investigating the mechanisms underlying this attenuation, which include local metabolic mechanisms, desensitization of mechanosensitive pathways, and reduced efficacy of the muscle pump. In 10 healthy subjects, short sequences of mechanical compressions ( n = 3–6; 150 mmHg) of the lower leg were delivered at different interstimulus intervals (ranging from 20 to 160 s) through a customized pneumatic device. Hemodynamic monitoring included near-infrared spectroscopy, detecting tissue oxygenation and blood volume in calf muscles, and simultaneous echo-Doppler measurement of arterial (superficial femoral artery) and venous (femoral vein) blood flow. The results indicate that 1) a long-lasting (>100 s) increase in local tissue oxygenation follows compression-induced hyperemia, 2) compression-induced hyperemia exhibits different patterns of attenuation depending on the interstimulus interval, 3) the amplitude of the hyperemia is not correlated with the amount of blood volume displaced by the compression, and 4) the extent of attenuation negatively correlates with tissue oxygenation ( r = −0,78, P < 0.05). Increased tissue oxygenation appears to be the key factor for the attenuation of hyperemia upon repetitive compressive stimulation. Tissue oxygenation monitoring is suggested as a useful integration in medical treatments aimed at improving local circulation by repetitive tissue compression. NEW & NOTEWORTHY This study shows that 1) the hyperemia induced by muscle compression produces a long-lasting increase in tissue oxygenation, 2) the hyperemia produced by subsequent muscle compressions exhibits different patterns of attenuation at different interstimulus intervals, and 3) the extent of attenuation of the compression-induced hyperemia is proportional to the level of oxygenation achieved in the tissue. The results support the concept that tissue oxygenation is a key variable in blood flow regulation.

scholarly journals Influence of Detector Size and Positioning on Near-Infrared Measurements and Iso-pathlength Point of Turbid Materials

2021 ◽  
Vol 9 ◽  
Author(s):  
Hamootal Duadi ◽  
Idit Feder ◽  
Dror Fixler
Keyword(s):  
Critical Parameter ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Experimental System ◽  
Optical Path ◽  
Optical Parameters ◽  
Infrared Measurements ◽  
Profile Changes ◽  
Physical Phenomena ◽  
Crossing Point

Measuring physical phenomena in an experimental system is commonly limited by the detector. When dealing with spatially defined behaviors, the critical parameter is the detector size. In this work, we examine near-infrared (NIR) measurements of turbid media using different size detectors at different positions. We examine cylindrical and semi-infinite scattering samples and measure their intensity distribution. An apparent crossing point between samples with different scatterings was previously discovered and named the iso-pathlength point (IPL). Monte Carlo simulations show the expected changes due to an increase in detector size or similarly as the detector’s location is distanced from the turbid element. First, the simulations show that the intensity profile changes, as well as the apparent IPL. Next, we show the average optical pathlength, and as a result, the differential pathlength factor, are mostly influenced by the detector size in the range close to the source. Experimental measurements using different size detectors at different locations validate the influence of these parameters on the intensity profiles and apparent IPL point. These findings must be considered when assessing optical parameters based on multiple scattering models. In cases such as NIR assessment of tissue oxygenation, size and location may cause false results for absorption or optical path.

Abstract 65: Evaluating the Role of Continuously Monitoring Regional Cerebral Oxygen Saturation in Predicting the Return of Spontaneous Circulation in Cardiac Arrest Patients: Does the Use of an Electrocardiogram Alone Provide Adequate Information During Cardiopulmonary Resuscitation?

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Hitoshi Kano ◽  
Tomoyo Saito ◽  
Toshihisa Matsui ◽  
Akio Endo ◽  
Masaki Nagama ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Oxygen Saturation ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Oxygenation Index ◽  
Cerebral Oxygen Saturation ◽  
Infrared Light ◽  
Cerebral Oxygen ◽  
Regional Cerebral Oxygen Saturation ◽  
Brain Tissue Oxygenation

During CPR as it is currently administered, treatments are selected from an algorithm derived by monitoring with ECG alone. One of the reasons for this is that no other devices are presently thought to be effective in helping to make treatment determinations. Monitoring of regional cerebral oxygen saturation with near infrared light is non-invasive and provides information on brain tissue oxygenation and hemodynamics. The results of our study suggest that measurements derived from continuously monitoring regional cerebral oxygen saturation during CPR can be considered an effective method of predicting the ROSC in cardiac arrest patients. Methods: In 95 patients with out-of-hospital cardiac arrest, the tissue oxygenation index (TOI) was continuously monitored (NIRO-200NX, Hamamatsu Photonics). We investigated the following parameters with respect to whether or not ROSC was achieved: TOI value at the contact of patients (initial TOI); TOI value just before ROSC (pre-ROSC TOI); and the maximum TOI during CPR (maximum TOI). Results: All the patients monitored received treatment with shocks or drugs and the initial TOI was 35.3±7.3%. For 74 patients who did not achieve ROSC, the maximum TOI was 41.0±7.4%, whereas for 21 patients who did achieve ROSC, the pre-ROSC TOI was 51.3±3.6% and the maximum TOI was 64.3±11.4%. ROSC was not achieved in the patients with maximum TOI below 45%. Conclusion: The pre-ROSC TOI was significantly higher than the maximum TOI in the patients who did not achieve ROSC which suggests the possibility of predicting ROSC by monitoring the increase in TOI. In cases where the TOI remains low, there is a possibility that ROSC should not be expected. In such cases, it may be desirable to attempt to improve the quality of CPR to increase the TOI before delivering shocks or administering drugs.

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