LEAK-COMPENSATED PROPORTIONAL ASSIST VENTILATION
First Claim
1. A method of compensating for leakage in a ventilation system during delivery of proportional assist ventilation to a patient comprising:
- monitoring an instantaneous flow in the ventilation system based on one or more measurements of pressure and flow in the ventilation system;
modeling leakage from the ventilation system as a first leakage component through a first orifice of a fixed size and a second leakage component through a second orifice of a varying size, wherein the first and second leakage components are different functions of instantaneous pressure in the ventilation system;
estimating a leak-compensated instantaneous lung flow of gas inhaled or exhaled by the patient based on the one or more measurements, the first leakage component and second leakage component;
using the leak-compensated lung flow and a predetermined respiratory mechanics model to estimate a leak-compensated lung compliance and a leak-compensated lung resistance; and
calculating a pressure to be delivered to the patient based on the leak-compensated lung flow, the leak-compensated lung compliance and the leak-compensated lung resistance.
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Accused Products
Abstract
This disclosure describes systems and methods for compensating for leakage when during delivery of gas from a medical ventilator in a proportional assist mode to a patient. The technology described herein includes systems and methods to compensate the delivery of PA ventilation for leakage in the patient circuit by using leak-compensated lung flows as well as leak-compensated respiratory mechanics parameters (lung compliance and lung resistance) estimated in a manner that compensates for elastic and inelastic leaks from the ventilation system.
185 Citations
20 Claims
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1. A method of compensating for leakage in a ventilation system during delivery of proportional assist ventilation to a patient comprising:
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monitoring an instantaneous flow in the ventilation system based on one or more measurements of pressure and flow in the ventilation system; modeling leakage from the ventilation system as a first leakage component through a first orifice of a fixed size and a second leakage component through a second orifice of a varying size, wherein the first and second leakage components are different functions of instantaneous pressure in the ventilation system; estimating a leak-compensated instantaneous lung flow of gas inhaled or exhaled by the patient based on the one or more measurements, the first leakage component and second leakage component; using the leak-compensated lung flow and a predetermined respiratory mechanics model to estimate a leak-compensated lung compliance and a leak-compensated lung resistance; and calculating a pressure to be delivered to the patient based on the leak-compensated lung flow, the leak-compensated lung compliance and the leak-compensated lung resistance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of compensating for leakage in a ventilation tubing system during delivery of gas from a medical ventilator to a patient comprising:
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receiving a support setting identifying an amount of proportional assistance to provide to the patient; identifying an inelastic leakage in the ventilation tubing system as a first function of at least one of a pressure measurement and a flow measurement in the ventilation tubing system; identifying an elastic leakage in the ventilation tubing system as a second function of at least one of the pressure measurement and the flow measurement in the ventilation tubing system; estimating circuit compliance and circuit resistance of the ventilation tubing system; estimating a lung compliance of the patient and a lung resistance of the patient based on the inelastic leakage, the elastic leakage, the circuit compliance, circuit resistance and the at least one of the pressure measurement and the flow measurement in the ventilation tubing system; delivering ventilation to the patient based on patient effort and the support setting, wherein the patient effort is determined from the inelastic leakage, the elastic leakage, the lung compliance, the lung resistance and the at least one of the pressure measurement and the flow measurement in the ventilation tubing system. - View Dependent Claims (12, 13)
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14. A pressure support system comprising:
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a pressure generating system adapted to generate a flow of breathing gas; a ventilation tubing system including a patient interface device for connecting the pressure generating system to a patient; one or more sensors operatively coupled to the pressure generating system or the ventilation tubing system, each sensor capable of generating an output indicative of a pressure of the breathing gas; a leak estimation module that identifies leakage in the ventilation tubing system; a respiratory mechanics calculation module that generates a leak-compensated lung compliance and a leak-compensated lung resistance based on the leakage and at least one output indicative of a pressure of the breathing gas; and a proportional assistance ventilation module that causes the pressure generating system to provide ventilation to the patient based on patient effort and a support setting, wherein the patient effort is determined from the leakage, the leak-compensated lung compliance and the leak-compensated lung resistance. - View Dependent Claims (15, 16, 17, 18)
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19. A controller for a medical ventilator comprising:
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a microprocessor; a module that compensates calculations of lung compliance and lung resistance based on instantaneous elastic leakage and instantaneous inelastic leakage of breathing gas from a ventilation tubing system; and a pressure generating module controlled by the microprocessor that provides proportional assist ventilation based on the compensated lung compliance and lung resistance. - View Dependent Claims (20)
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Specification