An apparatus comprising: a base (12) for supporting a medical patient and, a humidifier module (20) removably coupled to the base (12), the humidifier module (20) including a main reservoir (50) and an evaporator reservoir (52) separated by a channel (70) wherein the humidifier module (20) further comprises a cover (58) coupled to one of the main reservoir (50) or the evaporator reservoir (52) with a post (76) extending outwardly therefrom, such that the post (76) is disposed within the channel (48) when the cover (58) is closed and, wherein the post (76) includes a slot (78) disposed therein which permits the flow of fluid between the main reservoir (50) and the evaporator reservoir (52).
