LEAK-COMPENSATED RESPIRATORY MECHANICS ESTIMATION IN MEDICAL VENTILATORS
First Claim
1. A method of compensating for leakage in a ventilation system during delivery of gas from a medical ventilator to a patient comprising:
- monitoring an instantaneous flow in the ventilation system based on one or more measurements of pressure and flow in ventilation system;
modeling leakage 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; and
using the leak-compensated lung flow and a predetermined respiratory mechanics model to estimate at least one of a leak-compensated lung compliance and a leak-compensated lung resistance.
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Accused Products
Abstract
This disclosure describes systems and methods for compensating for leakage when determining the respiratory mechanics of a patient during delivery of gas from a medical ventilator to a patient. The systems and methods include monitoring an instantaneous flow in the ventilation system based on one or more measurements of pressure and flow in ventilation system. The leakage is modeled using a predetermined leakage model. A leak-compensated instantaneous lung flow of gas inhaled or exhaled by the patient is estimated. Using the leak-compensated lung flow and a predetermined respiratory mechanics model, the respiratory mechanics of a patient may be estimated including at least one of a leak-compensated lung compliance and a leak-compensated lung resistance. The method may include using a dynamic respiratory mechanics model or a static respiratory mechanics model that requires use of a pause maneuver to collect the necessary data.
254 Citations
21 Claims
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1. A method of compensating for leakage in a ventilation system during delivery of gas from a medical ventilator 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 ventilation system; modeling leakage 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; and using the leak-compensated lung flow and a predetermined respiratory mechanics model to estimate at least one of a leak-compensated lung compliance and a leak-compensated lung resistance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. 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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identifying an inelastic leakage in the ventilation 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 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; and estimating one or more of 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 system. - View Dependent Claims (13, 14)
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15. 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 processor; a leak estimation module that identifies an elastic leakage associated with the ventilation tubing system and calculates a leak-compensated lung flow; and a respiratory mechanics calculation module that generates at least one of a leak-compensated lung resistance and a leak-compensated lung compliance based on the elastic leakage and at least one output indicative of a pressure of the breathing gas. - View Dependent Claims (16, 17, 18, 19)
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20. A controller for a medical ventilator comprising:
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a microprocessor; and a module that compensates calculations of lung compliance and lung resistance based on instantaneous elastic leakage and instantaneous inelastic leakage of breathing gas from an associated ventilation tubing system. - View Dependent Claims (21)
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Specification