A medical device including elongate probe defining proximal and distal ends and a thermally-transmissive region at its distal end, the elongate probe including a first fluid supply line in fluid communication with the thermally-transmissive region. A second fluid supply line is provided in fluid communication with the thermally-transmissive region, the second fluid supply line being connected to the elongate probe separately from the first fluid supply line. An exhaust line in fluid communication with the first and second fluid supply lines.