Abstract: In various embodiments, two or more electronic flow selectors of an electronic fluid flow control system may be used to control the flow rates of multiple fluids. In a total flow control mode, a first electronic flow selector may be used to select a total flow rate of two or more fluids. A second electronic flow selector may be used to select a flow rate or ratio of a flow rate of one fluid to the total flow rate of the two or more fluids. In a direct flow control mode, each electronic flow selector may be used to select a flow rate of a unique fluid. One of the fluids may be oxygen, and the other fluid, a balance gas, may be selected as either nitrous oxide or air using an electronic balance gas selector.

Abstract: A method and an apparatus for monitoring and controlling flows in medical equipment including an anesthetic machine and a ventilator for influencing a patient's respiratory system are disclosed. The apparatus includes a microprocessor and an airway system including drive gas conduits provided with an inhalation valve (2) and an exhalation valve (5) for gas discharging as well as a ventilator end flow sensor (3) for measuring the introduced or discharged drive gas flow through the valves. The airway system also includes patient end breathing tubing in which a patient end flow sensor (11) for measuring the patient's inspired and expired gas flow is provided. By comparing the measured values of the two flow sensors against the characteristic curve of the inhalation valve (2), the microprocessor can judge the operation states and accuracy of the respective flow sensors and the inhalation valve (2).