EFFECT OF ELECTRODE BELT USED FOR LUNG MONITORING WITH ELECTRICAL IMPEDANCE TOMOGRAPHY ON TIDAL VOLUME IN HEALTHY SUBJECTS

Electrical impedance tomography is a radiation free, non-invasive lung monitoring method that is increasingly coming to the forefront of the interest of researchers and clinicians. The most frequently used EIT system PulmoVista 500 (Dräger Medical, Germany) uses stiff silicone electrode belt that is applied around the patient’s thorax to monitor the distribution of ventilation. To achieve proper electrode-skin connection and obtain high-quality signal, the electrode belt needs to be placed tightly at the level of 4th to 6th intercostal space. There is a possibility that tightly placed belt affects the compliance of the chest wall, tidal volume, and respiratory effort of the patient. In this study, we monitored tidal volumes using spirometer in 10 healthy, spontaneously breathing volunteers with and without the electrode belt applied around the thorax. Potentially clinically significant, but not statistically significant changes occurred in 70% of the subjects during calm breathing and in 90% of the subjects during forced breathing. The study did not determine whether the use of the electrode belt increases or decreases the value of tidal volume. However, when monitoring lung ventilation with EIT system, the possible influence of the stiff electrode belt on chest wall compliance and tidal volumes should be considered.