Patient data controlled respiration system
First Claim
1. A respiration system for minimizing inspiration breathing gas oxygen partial pressure FiO2 while maintaining a desired arterial oxygen partial pressure PaO2 for a patient, including a respirator which supplies breathing gas to the patient at a plurality of respirator parameters, comprising:
- PaO2 sensor means for sensing actual arterial oxygen partial pressure of a patient and supplying a signal corresponding thereto;
mixing means for mixing oxygen plus at least one other gas to supply a breathing gas mixture having an actual oxygen partial pressure FiO2, value to the respirator,regulator means connected to said mixer for regulating the relative amounts of oxygen and the other gas in the breathing gas, said regulator means having a nominal PaO2 value and receiving the PaO2 sensor means signal for regulating the mixing means so that the actual PaO2 value approaches the PaO2 value;
comparator means connected to the mixing means and having a lower threshold value Su;
storage means connected to said mixing means and said comparator means for storing said actual FiO2 value and supplying that value as the So value to said comparator means for a subsequent comparison step of said comparator means, said comparator means comparing said actual FiO2 value from said mixing means with said Su and So values;
clocking means associated with said comparator means for establishing a time period as the duration of each comparison step;
parameter adjustment means connected to the respirator and the comparator means for selectively adjusting said plurality of respirator parameters, one at a time, in a selected direction and by a selected increment; and
control means operatively connected to said comparator means and said storage means for controlling the parameter adjustment means to select one of said plurality of respiratory parameters and adjust said one selected respiratory parameter in accordance with one of the following conditions;
(i) with the actual FiO2 value being between the Su and So values during a comparison step duration, the control means being operable to cause the parameter adjustment means to make an adjustment of said one parameter in a positive or negative direction, store the direction of said adjustment, and select another of said plurality of respiratory parameters for adjustment;
(ii) with the actual FiO2 value being outside the range between the Su and So values, said control means being operable to maintain the So value of the previous comparison step in said storage means, reverse the direction of adjustment of the previous selected parameter and adjust the previous selected parameter by a selected increment in the reverse direction, and adjust the one selected parameter in a position or negative direction.
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Abstract
A respiration system and method for minimizing the oxygen concentration of inspiration gas supplied to a patient while maintaining a desired arterial oxygen partial pressure in the patient comprising a regulator for changing the oxygen concentration of inspiration gas supplied to a respirator according to a desired nominal value therefor and a sensed value therefor taken from the patient, a control device for adjusting parameters of the breathing gas in the respirator supplied to the patient while maintaining the desired arterial oxygen partial pressure, and a minimizer connected to the control device for changing a direction of the adjustment when the oxygen concentration in the inspiration gas cannot be maintained within a range between a first sensed instantaneous value for the oxygen concentration in the inspiration gas and a lower limit set for that value.
126 Citations
7 Claims
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1. A respiration system for minimizing inspiration breathing gas oxygen partial pressure FiO2 while maintaining a desired arterial oxygen partial pressure PaO2 for a patient, including a respirator which supplies breathing gas to the patient at a plurality of respirator parameters, comprising:
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PaO2 sensor means for sensing actual arterial oxygen partial pressure of a patient and supplying a signal corresponding thereto; mixing means for mixing oxygen plus at least one other gas to supply a breathing gas mixture having an actual oxygen partial pressure FiO2, value to the respirator, regulator means connected to said mixer for regulating the relative amounts of oxygen and the other gas in the breathing gas, said regulator means having a nominal PaO2 value and receiving the PaO2 sensor means signal for regulating the mixing means so that the actual PaO2 value approaches the PaO2 value; comparator means connected to the mixing means and having a lower threshold value Su; storage means connected to said mixing means and said comparator means for storing said actual FiO2 value and supplying that value as the So value to said comparator means for a subsequent comparison step of said comparator means, said comparator means comparing said actual FiO2 value from said mixing means with said Su and So values; clocking means associated with said comparator means for establishing a time period as the duration of each comparison step; parameter adjustment means connected to the respirator and the comparator means for selectively adjusting said plurality of respirator parameters, one at a time, in a selected direction and by a selected increment; and control means operatively connected to said comparator means and said storage means for controlling the parameter adjustment means to select one of said plurality of respiratory parameters and adjust said one selected respiratory parameter in accordance with one of the following conditions; (i) with the actual FiO2 value being between the Su and So values during a comparison step duration, the control means being operable to cause the parameter adjustment means to make an adjustment of said one parameter in a positive or negative direction, store the direction of said adjustment, and select another of said plurality of respiratory parameters for adjustment; (ii) with the actual FiO2 value being outside the range between the Su and So values, said control means being operable to maintain the So value of the previous comparison step in said storage means, reverse the direction of adjustment of the previous selected parameter and adjust the previous selected parameter by a selected increment in the reverse direction, and adjust the one selected parameter in a position or negative direction. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of minimizing inspiration breathing gas oxygen partial pressure FiO2 while maintaining a desired arterial oxygen partial pressure PaO2 for a patient using a respirator which supplies breathing gas to the patient having a plurality of respirator parameters, comprising:
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(a) sensing the actual PaO2 value of the patient; (b) providing a nominal PaO2 value for the patient; (c) supplying the actual and nominal PaO2 values to a regulator which is connected to a gas mixer, for controlling the gas mixer to adjust an amount of oxygen provided in breathing gas for the mixer to the patient so that the actual PaO2 value can be made to approach the nominal PaO2 value, the breathing gas having an actual oxygen partial pressure value FiO2 ; (d) comparing the actual FiO2 value with upper and lower threshold values for the FiO2 value, So and Su, respectively; (e) storing the actual FiO2 value to act as the So value in a following comparison step; (f) automatically selecting a parameter of the plurality of parameters and modifying said parameter in accordance with one of the following conditions; (i) with the actual FiO2 value being between the stored So and the Su values, adjusting the selected parameter of the plurality of respirator parameters by a selected increment in a positive or negative direction, storing the direction of the adjustment, and repeating steps (a) to (f) for each respirator parameter; (ii) with the actual FiO2 value being out of the range between So and Su, maintaining the So value of a previous comparison step, reversing the stored direction of the adjustment of the previous selected respirator parameter and adjusting the previous selected parameter by a selected increment in the reverse direction, and repeating steps (a) to (f) for the selected respirator parameter.
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Specification