Importance

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Abstract

A reliable, pulse-flow supplemental oxygen apparatus for alleviating respiratory ailments is provided which yields substantial savings in oxygen while giving the patient the physiological equivalent of a prescribed continuous stream of oxygen. The apparatus preferably includes a demand oxygen valve operated in a pulse mode by means of electronic control circuitry which, through an appropriate sensor, monitors the patient's breathing efforts and gives a variable 'custom tailored' pulse volume of oxygen to the patient during the very initial stages of each inspiration. Pulse volume variability is based upon a measured parameter characterizing at least a part of one and preferably a plurality of the patient's preceding breaths; advantageously, the elapsed time interval of the patient's three preceding breath cycles is measured to effectively measure breath rate. These breath-characterizing parameters, together with data characterizing the prescribed continuous oxygen flow to be matched, enable the apparatus to give the desired 'on the go' dose variability. The apparatus is also designed to revert to conventional, continuous-flow operation upon a power failure or circuit malfunction, and for this purpose a specialized dual flow control restrictor valve is provided in the form of the invention designed for hospital use. In the event of abnormally low or high breath rates on the part of the patient, the device automatically delivers a relatively long continuous pulse, then stops to again sample the breath rate. If the rate is normal, the usual pulse flow operation is resumed; if the rate remains abnormal, the long pulse volume-rate sampling is repeated. Actual tests with the apparatus hereof demonstrate an oxygen saving of over 50% as compared with continuous flow regimens.

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First Claim