Abstract: The respirator circuit of which the present invention is a part includes a water cascade for humidification of the air, oxygen enriched air or pure oxygen from a conventional respirator. From the cascade a first conduit tube portion connects to a first branch of a Y fitting, a second branch thereof connects a second conduit tube portion to a spirometer, and the main Y fitting leg connects to a conventional endotracheal tube. The improvement that is the focus of this invention is a secondary suction tube or aspirator which is located in close relation to the lowermost main length of the circuit conduits and a plurality of perforations connect between and along the lengths of the main circuit and suction tubes.