Determination of patient circuit disconnect in leak-compensated ventilatory support
First Claim
1. A method of detecting disconnection of a ventilation system during delivery of gas from a medical ventilator to a patient, the ventilation system comprising a processor and a memory, the method comprising:
- developing, by the ventilation system, an actual leakage equation describing leakage from the ventilation system as a function of pressure in the ventilation system, wherein developing the actual leakage equation comprises;
taking one or more measurements of instantaneous pressure or instantaneous flow in the ventilation system during a period of delivery of gas to the patient;
determining an actual leakage from the ventilation system during the period;
based on the one or more measurements and the actual leakage for the period, modeling the actual 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 pressure in the ventilation system; and
developing the actual leakage equation based on the first and second leakage components;
developing a maximum leakage equation describing a maximum allowed leakage from the ventilation system as a function of pressure in the ventilation system;
monitoring pressure in the ventilation system during delivery of gas to the patient during a breath;
calculating an actual breath leakage from the ventilation system during the breath based on a current pressure using the actual leakage equation;
calculating a maximum allowed leakage from the ventilation system during the breath based on the current pressure using the maximum leakage equation; and
comparing the calculated maximum allowed leakage and the actual breath leakage.
2 Assignments
0 Petitions
Accused Products
Abstract
This disclosure describes systems and methods for detecting disconnect conditions in a ventilator. The disclosure describes a model-based enhancement to conventional disconnect detection. The methods and systems described herein compensate for the additional leakage that occurs due to inelastic and elastic leaks in the ventilation system. One method described includes calculating the actual leakage from the ventilation system including leaks from elastic leakage and inelastic leakage based on measurements of pressure and flow in the ventilation system for a breath and then comparing this leakage to a calculated hypothetical maximum allowable leakage determined based on an operator-selected maximum allowable leakage and the measurements of pressure for the same breath. Disconnection is assumed if the actual leakage is greater than the maximum allowable leakage.
-
Citations
15 Claims
-
1. A method of detecting disconnection of a ventilation system during delivery of gas from a medical ventilator to a patient, the ventilation system comprising a processor and a memory, the method comprising:
-
developing, by the ventilation system, an actual leakage equation describing leakage from the ventilation system as a function of pressure in the ventilation system, wherein developing the actual leakage equation comprises; taking one or more measurements of instantaneous pressure or instantaneous flow in the ventilation system during a period of delivery of gas to the patient; determining an actual leakage from the ventilation system during the period; based on the one or more measurements and the actual leakage for the period, modeling the actual 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 pressure in the ventilation system; and developing the actual leakage equation based on the first and second leakage components; developing a maximum leakage equation describing a maximum allowed leakage from the ventilation system as a function of pressure in the ventilation system; monitoring pressure in the ventilation system during delivery of gas to the patient during a breath; calculating an actual breath leakage from the ventilation system during the breath based on a current pressure using the actual leakage equation; calculating a maximum allowed leakage from the ventilation system during the breath based on the current pressure using the maximum leakage equation; and comparing the calculated maximum allowed leakage and the actual breath leakage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method of detecting disconnection of a ventilation system during delivery of therapy to a patient, the ventilation system comprising a processor and a memory, the method comprising:
-
generating, by the ventilation system, an actual leak equation based on a leak model and measurements taken during the delivery of therapy to the patient, wherein the leak model models leakage from the ventilator circuit 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 pressure in the ventilation system; generating a maximum leak equation based on the leak model, and a maximum allowed leakage at a specified pressure; measuring pressure in the ventilation system during a current therapy period; and calculating an actual leak from the ventilation system for the current therapy period based on the pressure using the actual leak equation; calculating a maximum allowable leak from the ventilation system for the current therapy period based on the pressure using the maximum leak equation; and selecting, based on a comparison of the actual leak and the maximum allowable leak, one of at least two ventilator connection states. - View Dependent Claims (12, 13, 14, 15)
-
Specification