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The effect of basic assumptions on the tissue oxygen saturation value of near infrared spectroscopy


Metz, Andreas Jaakko; Biallas, Martin; Jenny, Carmen; Muehlemann, Thomas; Wolf, Martin (2013). The effect of basic assumptions on the tissue oxygen saturation value of near infrared spectroscopy. In: Welch, William J. Oxygen Transport to Tissue XXXIV. New York: Springer, 169-175.

Abstract

Tissue oxygen saturation (StO(2)), a potentially important parameter in clinical practice, can be measured by near infrared spectroscopy (NIRS). Various devices use the multi-distance approach based on the diffusion approximation of the radiative transport equation [1, 2]. When determining the absorption coefficient (μ (a)) by the slope over multiple distances a common assumption is to neglect μ (a) in the diffusion constant, or to assume the scattering coefficient [Formula: see text] to be constant over the wavelength. Also the water influence can be modeled by simply subtracting a water term from the absorption. This gives five approaches A1-A5. The aim was to test how these different methods influence the StO(2) values. One data set of 30 newborn infants measured on the head and another of eight adults measured on the nondominant forearm were analyzed. The calculated average StO(2) values measured on the head were (mean ± SD): A1: 79.99 ± 4.47%, A2: 81.44 ± 4.08%, A3: 84.77 ± 4.87%, A4: 85.69 ± 4.38%, and A5: 72.85 ± 4.81%. The StO(2) values for the adult forearms are: A1: 58.14 ± 5.69%, A2: 73.85 ± 4.77%, A3: 58.99 ± 5.67%, A4: 74.21 ± 4.76%, and A5: 63.49 ± 5.11%. Our results indicate that StO(2) depends strongly on the assumptions. Since StO(2) is an absolute value, comparability between different studies is reduced if the assumptions of the algorithms are not published.

Abstract

Tissue oxygen saturation (StO(2)), a potentially important parameter in clinical practice, can be measured by near infrared spectroscopy (NIRS). Various devices use the multi-distance approach based on the diffusion approximation of the radiative transport equation [1, 2]. When determining the absorption coefficient (μ (a)) by the slope over multiple distances a common assumption is to neglect μ (a) in the diffusion constant, or to assume the scattering coefficient [Formula: see text] to be constant over the wavelength. Also the water influence can be modeled by simply subtracting a water term from the absorption. This gives five approaches A1-A5. The aim was to test how these different methods influence the StO(2) values. One data set of 30 newborn infants measured on the head and another of eight adults measured on the nondominant forearm were analyzed. The calculated average StO(2) values measured on the head were (mean ± SD): A1: 79.99 ± 4.47%, A2: 81.44 ± 4.08%, A3: 84.77 ± 4.87%, A4: 85.69 ± 4.38%, and A5: 72.85 ± 4.81%. The StO(2) values for the adult forearms are: A1: 58.14 ± 5.69%, A2: 73.85 ± 4.77%, A3: 58.99 ± 5.67%, A4: 74.21 ± 4.76%, and A5: 63.49 ± 5.11%. Our results indicate that StO(2) depends strongly on the assumptions. Since StO(2) is an absolute value, comparability between different studies is reduced if the assumptions of the algorithms are not published.

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Additional indexing

Item Type:Book Section, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Neonatology
04 Faculty of Medicine > Center for Integrative Human Physiology
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Language:English
Date:2013
Deposited On:09 Nov 2012 15:04
Last Modified:07 Dec 2017 16:08
Publisher:Springer
Series Name:Advances in Experimental Medicine and Biology
Number:765
ISSN:0065-2598
ISBN:978-1-4614-4771-9 (Print) 978-1-4614-4989-8 (Online)
Publisher DOI:https://doi.org/10.1007/978-1-4614-4989-8_24
Related URLs:http://opac.nebis.ch/F/?local_base=EBI01&con_lng=GER&func=find-b&find_code=090&request=002076523
PubMed ID:22879030

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