A sensor guide wire for intravascular measurement of a physiological variable includes a sensor element arranged in a jacket in a sensor region of the sensor guide wire, a core wire extending at least partly along the length of the sensor guide wire, and at least one electrical lead connected to the sensor element. The jacket is tubular and includes proximal and distal end openings, a jacket wall, a first opening arranged in the jacket wall, and a second opening arranged in the jacket wall. The first and second openings are proximate to the sensor element, and the core wire is adapted to extend through the jacket via the proximal and distal end openings. The sensor guide wire can provide a more reliable and stable sensor output by preventing air from becoming entrapped within the jacket wall or allowing such entrapped air to escape. The sensor guide wire may also prevent air from adhering to the outer surface of the jacket wall by enabling improved fluid communication between the sensor element and a fluid medium.
