A description is given of a gas separation device for a physiological
fluid, comprising a containing body (6) having at least a first inlet
aperture (7) for a physiological fluid, positioned with a tangential
direction of access, at least one outlet aperture (9) for the said fluid,
spaced apart from the said inlet aperture, and a guide element (17)
housed within the said body. The guide element (17) has a continuous
active surface (15) designed to contact and guide the said fluid and
delimits, together with the containing body (6), a first annular chamber
(20) into which the first inlet aperture (7) opens directly.