Abstract: A detector device delivering a signal representative of the respiration of patient, adapted to be used in a charged and sensitive electromagnetic environment. The device is principally constituted by at least two non-metallic electrodes (1) and by a unit for the processing of electrical signals emitted by the heart, comprising a first module (5) for acquiring and shaping cardiac electric signals, a second module (6) for extraction of the respiratory signal, and a third module (7) for electro-optical conversion of this latter, the modules being disposed in a shielded casing (8) forming a Faraday cage and, finally, by an optical connection (9) connecting the casing (8) to at least one other apparatus or device.