Apparatus for providing a controlled flow of intravenous fluid to a

Abstract

Apparatus provides a controlled flow of fluid at particular rates from a source to a patient at controlled pressures of low value. The apparatus includes an input line connected to the source. An output line extends to the patient and implementing means such as a pump implements the flow of fluid from the input line to the output line at a particular rate. The source is disposed a particular distance above the implementing means to produce a particular pressure of the fluid at the implementing means and to provide this particular pressure to the fluid flowing to the patient. A bypass line is connected across the implementing means. Means in the bypass line, such as a chamber and a flexible diaphragm in the chamber, isolate the input side of the bypass line against the flow of fluid to the output side of the bypass line. Hydrophilic membrane means may be provided between the bypass line and the implementing means to provide for a passage of fluid from the input line to the bypass line and to prevent a passage of air bubbles from the bypass line to the input line. Hydrophilic membrane means may also be provided between the output line and the bypass line for similar purposes. Means may be disposed in the output side of the bypass line to sense the presence of liquid. Such sensing of liquid indicates a pressure of fluid in the output line greater than the pressure of the fluid in the input line at the position of the implementing means. This may result from an obstruction in the output line or an improper operation of the implementing means. When the sensing means becomes operative, the operation of the implementing means is discontinued and aural and/or visual alarms are energized.