Model for calculating skin perfusion from heat flux measured with a double heated transcutaneouspO2electrode
- 1 January 1988
- journal article
- research article
- Published by Taylor & Francis in Scandinavian Journal of Clinical and Laboratory Investigation
- Vol. 48 (sup189) , 21-25
- https://doi.org/10.1080/00365518809168183
Abstract
The heat flux q into the skin from a heated transcutaneous pO2 electrode depends on the blood flow rate in the skin. Previous studies by Jaszczak et al. have provided a model for calculating the ‘areic’ blood flow rate, i.e. the blood flow rate divided by surface area. The calculation requires measuring the heat flux with and without blood flow, q1 and q2, and knowing the core temperature under the electrode Tc. The present model provides an equation for calculating the ‘volumic’ blood flow rate, i.e. the blood flow rate divided by skin volume: where a is the thermal diffusivity of the skin (0.13 10-6 m2/s), lc is a depth parameter, and R is the ratio (q1-q2)/q2. lC, TC, and q2 are related by: q2=· (TE - TC)/lC where TE is the electrode temperature and X is the thermal conductivity of the skin (0.544 W/(m K). If standard values for lC and TC are used, measuring the heat flux after blood flow is stopped becomes superfluous. The experimental heat flux data of Jaszczak et al. measured with a special double thermostattet pO2 electrode at 45 °C placed on the volar side of the forearm provided a calculated blood flow of 64 (ml/min)/(100 ml) with the present model. This is about 60 % higher than their value measured with the 133Xe washout technique, but all approximations made in the present model tend to give too low rather than too high values.Keywords
This publication has 3 references indexed in Scilit:
- A Combined tc-Po2and Skin Blood Flow SensorActa Anaesthesiologica Scandinavica, 1985
- Determination of Skin Blood Flow by133Xe Washout and by Heat Flux from a Heated tc‐Po2ElectrodeActa Anaesthesiologica Scandinavica, 1984
- Estimation of Blood Flow in Transcutaneous PO2 MeasurementsActa Anaesthesiologica Scandinavica, 1983