초록 ▼

A digital system for use in controlling the cycling of a respirator includes a digital clock for dividing each respiratory cycle (inspiration and expiration) into a fixed number of counts. A respiratory rate circuit is adjusted to vary the frequency of the counts to define the total time of each res

A digital system for use in controlling the cycling of a respirator includes a digital clock for dividing each respiratory cycle (inspiration and expiration) into a fixed number of counts. A respiratory rate circuit is adjusted to vary the frequency of the counts to define the total time of each respiratory cycle (in breaths per minute). A respiration ratio circuit is independently adjusted to control the ratio of inspiration time to expiration time for each respiratory cycle by selecting a fixed number of counts to define a desired inspiration time. The remaining counts define expiration time. A digital-to-analog converter is driven in response to the counters to produce a voltage output defining a desired volume-versus-time waveform having the previously selected rate and ratio. The output from the digital-to-analog converter controls the cycling of a volume-cycled respirator. Read-only-memories may be inserted between the counters and the input to the digital-to-analog converter to generate a large number of different inspiration waveforms.

대표청구항 ▼

A system for digitally controlling an analog waveform signal to be used to control the respiratory cycle Of a respirator in which the respiratory cycle has an inspiratory phase and an expiratory phase, the digital system comprising: a. means for selecting a first input having a magnitude representat

A system for digitally controlling an analog waveform signal to be used to control the respiratory cycle Of a respirator in which the respiratory cycle has an inspiratory phase and an expiratory phase, the digital system comprising: a. means for selecting a first input having a magnitude representative of a predetermined respiratory rate defining the duration for each respiratory cycle; b. a digital respiratory rate circuit having means responsive to said first input for producing a first output comprising a series of time pulses having a frequency proportional to the magnitude of said first input; c. means for selecting a second input having a magnitude representative of a predetermined respiratory ratio defining the duration of the inspiratory phase relative to the duration of the expiratory phase for each respiratory cycle, the magnitude of the second input being independent of the magnitude of the first input; d. a digital respiratory ratio circuit for defining the inspiratory portion of each respiratory cycle, the ratio circuit having means responsive to the second input and to the output of the rate circuit for generating a second output comprising a constant number of timed pulses corresponding to the inspiratory phase of each respiratory cycle in which the portion of each cycle during which said constant number of pulses occur is proportional to said preselected respiratory ratio, and the frequency of said constant number of pulses is proportional to the frequency of pulses generated by the rate circuit, said constant number of pulses being independent of said preselected respiratory rate and ratio; and e. means responsive to the output pulses from the respiratory ratio circuit for converting said pulses into an analog waveform signal having magnitude with respect to time which varies in proportion to said preselected respiratory rate and ratio.