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Your search keyword '"Tobias Lindbergh"' showing total 2 results
Start Over Author "Tobias Lindbergh" Journal journal of biomedical optics
2 results on '"Tobias Lindbergh"'

1. Intramyocardial oxygen transport by quantitative diffuse reflectance spectroscopy in calves

Author

Tobias Lindbergh, Zoltán Szabó, Marcus Larsson, Tomas Strömberg, and Henrik Casimir-Ahn

Subjects
medicine.medical_specialty, Diffuse reflectance infrared fourier transform, Biomedical Engineering, chemistry.chemical_element, Biological Transport, Active, Oxygen, Sensitivity and Specificity, Biomaterials, chemistry.chemical_compound, Nuclear magnetic resonance, Fibre optic sensors, medicine, Animals, Statistical analysis, Oximetry, Myocardium, Spectrum Analysis, Oxygen transport, Reproducibility of Results, Reflectivity, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Surgery, Tissue optics, chemistry, Myoglobin, Cattle
Abstract

Intramyocardial oxygen transport was assessed during open-chest surgery in calves by diffuse reflectance spectroscopy using a small intramuscular fiber-optic probe. The sum of hemo- and myoglobin tissue fraction and oxygen saturation, the tissue fraction and oxidation of cytochrome aa3, and the tissue fraction of methemoglobin were estimated using a calibrated empirical light transport model. Increasing the oxygen content in the inhaled gas, 21%-50%-100%, in five calves (group A) gave an increasing oxygen saturation of 19+/-4%, 24+/-5%, and 28+/-8% (p0.001, ANOVA repeated measures design) and mean tissue fractions of 1.6% (cytochrome aa3) and 1.1% (hemo- and myoglobin). Cardiac arrest in two calves gave an oxygen saturation lower than 5%. In two calves (group B), a left ventricular assistive device (LVAD pump) was implanted. Oxygen saturation in group B animals increased with LVAD pump speed (p0.001, ANOVA) and with oxygen content in inhaled gas (p0.001, ANOVA). The cytochrome aa3 oxidation level was above 96% in both group A and group B calves, including the two cases involving cardiac arrest. In conclusion, the estimated tissue fractions and oxygenation/oxidation levels of the myocardial chromophores during respiratory and hemodynamic provocations were in agreement with previously presented results, demonstrating the potential of the method.

Published
2010

2. Myocardial tissue oxygenation estimated with calibrated diffuse reflectance spectroscopy during coronary artery bypass grafting.

Author

Erik Ha¨ggblad, Tobias Lindbergh, M. G. Daniel Karlsson, Henrik Casimir-Ahn, E. Go¨ran Salerud, and Tomas Stro¨mberg

Subjects
*CORONARY artery bypass, *TRANSPLANTATION of organs, tissues, etc., *MYOCARDIUM, *FIBER optics, *LIGHT absorption, *LIGHT scattering
Abstract

We present a study using a method able to assess tissue oxygenation, taking into account the absorption and the level of scattering in myocardial tissue using a calibrated fiber optic probe. With this method, interindividual comparisons of oxygenation can be made despite varying tissue optical properties during coronary artery bypass grafting (CABG). During CABG, there are needs for methods allowing continuous monitoring and prediction of the metabolism in the myocardial tissue. 14 patients undergoing CABG are investigated for tissue oxygenation during different surgical phases using a handheld fiber optic spectroscopic probe with a source-detector distance of less than 1 mm. The probe is calibrated using a light transport model, relating the absorption and reduced scattering coefficients (μa and μs′) to the measured spectra. By solving the inverse problem, absolute measures of tissue oxygenation are evaluated by the sum of oxygenized hemoglobin and myoglobin. Agreement between the model and measurements is obtained with an average correlation coefficient R2 of 0.96. Oxygenation is found to be significantly elevated after aorta cross-clamping and cardioplegic infusion, as well as after reperfusion, compared to a baseline (p<0.05). Tissue oxygenation decreases during cardiac arrest and increases after reperfusion. [ABSTRACT FROM AUTHOR]

Published
2008
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