Abstract: The present invention relates to a ventilator system which utilizes a control valve to assist an attendant in disconnecting a ventilator conduit circuit from a patient's endotracheal tube. Prior to the present invention, when a ventilator system was operated in certain modes, disconnection of the endotracheal tube from the ventilator circuit caused water which may have accumulated in the ventilator circuit to spray over the patient and/or attendant. In the present invention, a control valve is connected between the outlet of the ventilator circuit and the patient's endotracheal tube. Normally, the valve is maintained in the open position to permit air to be supplied to the patient. However, when it is desired to disconnect the ventilator circuit from the patient's endotracheal tube, the control valve can be manually closed immediately prior to disconnecting the ventilator circuit, thereby preventing the spraying of any accumulated water.