The effect of electrode belt size selection upon evaluation of the distribution of ventilation using electrical impedance tomography

Electrical impedance tomography (EIT) is a noninvasive diagnostic method enabling imaging of planar distribution of thorax impedance. Since EIT is not a routine tool in clinical practice, the examination methods have not been standardized yet. EIT system PulmoVista 500 (Dräger Medical, Germany) uses an electrode belt with 16 equally distributed electrodes and with several options for its fastening around the thorax. The manufacturer produces five sizes of the belts that partly overlap. There are several groups of patients that can use both a smaller and bigger belt. The aim of this study is to investigate whether there is a significant difference in evaluation of regional ventilation using EIT in case of using two sizes of electrode belt in the same subject and therefore the even distribution of electrodes is not maintained. Thirty healthy subjects were measured in horizontal and vertical position with two belt sizes separately. Significant differences in distribution of ventilation when comparing two belt sizes were found.