Apparatus for the infusion of a labor-inducing drug into the bloodstream of a patient
First Claim
1. A control system for controlling the infusion rate of a labor-inducing drug into the bloodstream of a patient comprising, means responsive to a control signal determined by the intra-uterine pressure of the patient for producing a train of pulses wherein each successive pulse corresponds to a contraction of the patient'"'"'s uterus and wherein the duration of each pulse is representative of the duration of the corresponding contraction, means responsive to the train of pulses for generating a first signal representative of the average value of the mark-space ratio of the pulse train, and means responsive to said first signal for deriving a second signal for increasing the infusion rate when the said average value is less than a first predetermined value and for reducing the infusion rate when the average value exceeds the said first predetermined value.
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Abstract
Apparatus for controlling the infusion rate of a labor-inducing drug as a function of the rate of uterine contraction includes means for producing a constant amplitude pulse train with the pulse duration determined by the duration of uterine contraction. The pulse train is integrated to produce a signal by means of which the infusion rate can be controlled automatically.
9 Citations
23 Claims
- 1. A control system for controlling the infusion rate of a labor-inducing drug into the bloodstream of a patient comprising, means responsive to a control signal determined by the intra-uterine pressure of the patient for producing a train of pulses wherein each successive pulse corresponds to a contraction of the patient'"'"'s uterus and wherein the duration of each pulse is representative of the duration of the corresponding contraction, means responsive to the train of pulses for generating a first signal representative of the average value of the mark-space ratio of the pulse train, and means responsive to said first signal for deriving a second signal for increasing the infusion rate when the said average value is less than a first predetermined value and for reducing the infusion rate when the average value exceeds the said first predetermined value.
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13. Apparatus for the infusion of a labor-inducing drug into the bloodstream of a patient at an infusion rate controllable as a function of the rate of uterine contraction of the patient comprising, pumping means for infusing the drug at a rate dependent on the value of an infusion rate signal, applied thereto means for measuring the intra-uterine pressure of the patient and producing a control signal determined thereby, and a control system comprising:
- a comparison device which compares the control signal with a reference signal representing a predetermined intra-uterine pressure value to provide a train of pulses of substantially constant amplitude with each pulse of the pulse train corresponding to a contraction of the patient'"'"'s uterus for which the measured intra-uterine pressure is greater than the predetermined pressure, the duration of each pulse being representative of the duration of the corresponding contraction, integrating means responsive to said pulse train for generating a signal representative of the average value of the mark-space ratio of the pulse train, and means responsive to said signal for deriving said infusion rate signal which increases in value when said average value is less than a first predetermined value and which decreases in value when the average value is greater than the first predetermined value.
- View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
Specification