Ventilation distribution on different body positions measured by electrical impedance tomography

Objective: It has been confirmed that gravitation influences ventilation distribution. The aim of the study was to validate the ability of electrical impedance tomography (EIT) in detecting ventilation inhomogeneity caused by gravitation. Methods: Ten healthy volunteers were included for this prospective study. They were asked to breathe spontaneously in four different body positions, namely supine, prone, left lateral and right lateral positions. Functional EIT images were calculated and divided into four quadrants. Results: No significant difference of air distribution was found between gravity-dependent lung regions and nondependent lung regions in both supine and prone position, while significant difference was found in both lateral positions (left lateral, left and right lung respectively: 57.6±7.2%, 42.4±7.2%, p<;0.01; right lateral, left and right lung respectively:, 35.3±6.7%, 64.7±6.7%, p<;0.01). Conclusion: The results indicate that the influence of gravitation on ventilation distribution depends on body positions and EIT is able to detect the ventilation inhomogeneity.