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US 2015/0090264 A1Published application
Methods and systems for proportional assist ventilation
AssigneeCovidien LP
InventorNancy F. Dong
Life of this patent
Estimating the term…
Abstract
The systems and methods include providing a negative proportional assist breath type, a time adjusted negative proportional assist breath type, or a time adjusted proportional assist breath type during ventilation of a patient with a ventilator.
Claims20
A method for ventilating a patient with a ventilator comprising:
- delivering an initial inspiration pressure to a patient in a first computational cycle;
- retrieving a support setting;
- monitoring inspiration flow during the first computation cycle;
- estimating a first patient effort utilizing an inverse model based at least on the inspiration flow monitored during the first computational cycle;
- calculating a first target inspiration pressure based at least on the first estimated patient effort from the first computational cycle and the support setting;
- and
- delivering the first target inspiration pressure to the patient in a second computational cycle.
4 more elements
A method for ventilating a patient with a ventilator comprising:
- delivering an initial inspiration pressure to a patient in a first computational cycle;
- retrieving a support setting;
- monitoring inspiration flow during the first computational cycle;
- estimating a first patient effort utilizing at least the inspiration flow monitored during the first computational cycle;
- calculating a first target inspiration pressure based at least on the first estimated patient effort from the first computational cycle, the support setting, and a time delay caused by a control system of the ventilator;
- and
- delivering the first target inspiration pressure to the patient in a second computational cycle.
4 more elements
The method of claim 10, further comprising:
- monitoring the inspiration flow during the second computational cycle;
- estimating a second patient effort utilizing at least the inspiration flow monitored during the second computational cycle;
- calculating a second target inspiration pressure based at least on the second estimated patient effort from the second computational cycle, the support setting, and the time delay caused by the control system of the ventilator;
- and
- delivering the second target inspiration pressure to the patient in a third computational cycle.
2 more elements
A ventilator system comprising:
- a pressure generating system that generates a flow of breathing gas;
- a ventilation tubing system including a patient interface for connecting the pressure generating system to a patient;
- one or more sensors operatively coupled to at least one of the pressure generating system, the patient, and the ventilation tubing system, wherein the one or more sensors generate output indicative of at least an inspiration flow;
- an inverse model (IM) effort module that calculates an estimated patient effort for each computational cycle utilizing an inverse model based on the output indicative of at least the inspiration flow from a last computational cycle;
- and
- a negative proportional assist (NPA) module that receives a support setting, receives an estimated patient effort from the IM effort module for each computational cycle, calculates a target inspiration pressure based at least on the received support setting and the estimated patient effort received from the IM effort module for the last computational cycle, and sends instructions to the pressure generating system to deliver the calculated target inspiration pressure in a next computational cycle to the patient during a negative proportional assist (NPA) breath type,
- wherein the instructions sent by the IM effort module and the NPA module provide closed-loop ventilation that is a negative feedback system.
4 more elements
The ventilator system of claim 19, wherein the NPA module adjusts the target inspiration pressure utilizing a dynamic assist ratio with a following equation:
- P
- vent
-
- (
- t
- )
- =
- G
- _
- vent
-
- (
- s
- )
- ·
-
- -
- τ
- ^
-
- s
- ·
- β
- ·
-
- (
- t
- )
-
- (
- t
- )
-
- (
- t
- -
- τ
- ^
- )
-
-
- (
- t
- )
- wherein Pvent is a target inspiration pressure, is an estimated patient effort, t is time in the continuous domain, β is the support setting,
- β
- ·
-
- (
- t
- )
-
- (
- t
- )
-
- (
- t
- -
- τ
- ^
- )
- is the dynamic assist ratio, Gvent(s) is a transfer function representing dynamics of the control system with no delay, s denotes a complex variable in an s-domain, e is an exponential function, and {circumflex over (τ)} is an estimate of a control system delay.
60 more elements
Dependencies are inferred from the claim text.