Abstract: A respiration assistor (10) for use in an anaesthesia breathing system. The respiration assistor is intended to provide respiratory assistance for a patient (14) who is breathing spontaneously under anaesthesia in order that the patient's end-expired CO2 will be maintained at or near the normal physiological level. For this purpose, the respiration assistor incorporates a blower (15) which is located in series with a gas flow detector (20 or 39) and an electric control circuit (19) is provided for activating the blower (15) when inspired gas flow is detected by the detector (20 or 39). Also, the respiration assistor incorporates an expiratory valve (23) that is actuated to a closed condition when the blower is activated.

Abstract: A method of controlling the delivery-point temperature and vapor level of a gas which is conveyed through a delivery line from a heater/humidifier to a delivery point. The method is particularly applicable to apparatus for use in the medical field and it involves heating and humidifying the gas to a temperature T.sub.1 and to a vapor level W.sub.1 of less than 100% saturation, and controlling the temperature of the gas in the delivery line to provide for a lower temperature T.sub.2 which corresponds to a selected higher vapor level W.sub.2 at the delivery point.

Abstract: Apparatus for humidifying a gas stream comprises a transparent reservoir having a top cap and connected via a float controlled valve chamber beneath to a humidifying chamber. The valve maintains a desired water level in the humidification chamber which has a heated floor and gas inlet and outlet ports in its top. Gas flowing between the ports is humidified to a figure approaching 80% and has its temperature raised to a higher temperature than is required at a point of use. The humidified gas flows through a hose which controls the cooling of the humidified gas so that 100% saturation cannot occur until the gas reaches the outlet of the delivery hose at the point of use. The temperatures of the hose and humidification chamber are separately controlled by their own control loops. The float chamber, reservoir and humidification chamber are made of the transparent material and the float and humidification chambers share a common metallic base which is readily detachable for cleaning.