Physiological responsive control for an oxygen regulator

Claim 1

A control means for regulating a mixing apparatus which supplies a breathable fluid to a recipient in response to changes in the physiological needs of the recipient, said control means comprising: means for retaining a reference signal corresponding to the recipient's normal use of oxygen; adjustment means for changing said reference signal to provide different operational parameters for a recipient; a housing having a chamber therein and including means for receiving and retaining breathed fluid from the recipient for a predetermined time period to permit the carbon dioxide present in a single exhalation to be averaged with several exhalations and thereby establish a mean carbon dioxide level with respect to the predetermined time period; sensor means responsive to said mean carbon dioxide level in said chamber for creating a utilization signal corresponding to the recipient's use of oxygen; computation means connected to said sensor means for combining said reference signal with said utilization signal to develop an output signal; servomotor means responsive to said output signal for adjusting the mixing apparatus to match the oxygen component in said breathing fluid with that used by the recipient; means for modifying said output signal to account for changes in the fractional concentration of oxygen in the blood of the recipient due to changes in the minute ventilation associated with an inhalation period of the recipient; amplifier means responsive to said modified output signal for driving said servomotor in a direction which changes the proportion of oxygen in the breathable fluid communicated from the mixing apparatus to sustain the optimum physiological breathable fluid for said recipient; and indicator means connected to said servomotor for informing an operator of the percentage of oxygen in said breathing fluid supplied to the recipient.