PURPOSE: To make it possible to effectively and accurately control the total amount of sucked oxygen according to breathing, by letting the time to open a valve means be a value calculated by using the value indicated by a flow rate setting means, the pressure of a gaseous oxygen supply source, and the frequency of a patient's breathing, for pulsatively sending gaseous oxygen only during inspiratory phase synchronized with breathing. ;CONSTITUTION: A gaseous oxygen supply source 1 containing variation of pressure, is connected to a nose cannula 5 by a conduit. On the way along the conduit, a valve means 4 for switching on and off the sending of gaseous oxygen and an orifice means 10 for limiting the flow rate of gaseous oxygen, are arranged. To the piping on the inlet side of the valve means 4, a pressure sensor 2 for measuring the pressure of gaseous oxygen from the gaseous oxygen supply source 1, is connected. To the piping on the outlet side of the valve means 4, a breathing sensor 3 for sensing a patient's breathing phase, is also installed. The signal of a flow rate setting means 7 is sent to a control part 6. Then, in a calculating part of the control part 6, the average value of the data about the frequency of breathing for a plurality of past times of a patient's breathing, is determined, the time of the next expiratory phase is estimated, and the time to open the valve means 4 is calculated.;COPYRIGHT: (C)1996,JPO
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