Email: b.h.brown@sheffield.ac.uk
CompanyName: University of Sheffield
Country: UK
Abstract: Neonatal lungs – can absolute lung resistivity be measured non-invasively?
B H Brown, R A Primhak*, R H Smallwood, P Milnes, A J Narracott and M J Jackson*
Medical Physics and Clinical Engineering
University of Sheffield
* Child Health
University of Sheffield
Abstract: The electrical resistivity of lung tissue can be related to the structure
and composition of the tissue and also to the air content. Conditions such as
pulmonary oedema and emphysema have been shown to change lung resistivity. However,
direct access to the lungs to enable resistivity to be measured is very difficult.
We have developed a new method of using Electrical Impedance Tomographic measurements
on a group of 142 normal neonates to determine the absolute resistivity of lung
tissue. The methodology involved comparing the measured data with that from
a finite difference model of the thorax in which lung tissue resistivity could
be changed. A mean value of 5.7 ± 1.7 Ohm.m was found over the frequency
range 4 kHz to 813 kHz. This value is lower than that usually given for adult
lung tissue but consistent with the literature on the composition of the neonatal
lung and with structural modelling.