An assembly of devices designed to perform continuous bioimpedance measurements throughout a cross-section of the thorax, to provide real-time feedback of lung function during controlled, assisted or spontaneous ventilation. It typically consists of a mobile trolley, an electrically-powered unit with a monitor and controls, connecting cables, and an electrode chest belt (typically with 16-32 electrodes). The technique [electrical impedance tomography (EIT)] uses single-frequency, low-amplitude alternating current applied by a pair of electrodes whereby the generated electrical potentials at the body surface are continuously measured by other electrodes.