Abstract: An apparatus for testing pulmonary functions uses a hollow tube having a venturi therein and an aspirator orifice in the hollow tube adjacent the venturi. A pressure signal analogous to the flow of air through the hollow tube is generated in the aspirator orifice. Various means are provided to respond to the pressure at the aspirator orifice and a timed cut off of the aspirator orifice is provided for measuring the flow for a predetermined time period, such as one second, thereby indicating the forced expiratory volume for one second (FEV.sub.1) without having to blow into expansible chambers, such as bellows or bags to determine the volume of air passing through the tube. The apparatus is adapted to measure the total volume of air passing through the tube, or the total volume during a predetermined time period.

Abstract: A drainage control valve apparatus utilizes a pressure relief valve for opening upon a predetermined fluid pressure being applied thereto and a liquid column is used for holding the pressure relief valve open by the weight of the liquid column escaping past the pressure relief valve to apply a negative pressure to the back of a pressure relief valve element. A small opening or a check valve releases the suction column when drainage is complete to allow the pressure relief valve to close. The pressure relief valve may be a spring biased valve and may be adjusted by varying the compression on the spring. The unit may be attached to a patient's leg with a strap. A method of draining a bladder is provided having the steps of opening a pressure relief valve under bladder pressure in a catheter, holding the pressure relief valve open with the suction of a column of liquid formed by the liquid passing the opened pressure relief valve and releasing the pressure relief valve when drainage is substantially complete.