Method for controlling an expiratory valve in a ventilator
First Claim
1. A method for controlling an expiratory valve in a ventilator during expiration, said expiratory valve being disposed in an expiratory section of the ventilator, comprising the steps of:
- substantially completely opening said expiratory valve for a first interval, having a duration, in a first expiration;
during a second interval following said first interval in said first expiration, measuring pressure in said expiratory section of said ventilator;
during said second interval, controlling said expiratory valve to produce a predetermined end pressure in said expiratory section;
identifying at least one parameter related to controlling said expiratory valve in said second interval; and
in said second interval, determining from said parameter whether a duration of a first interval in a next-following, second expiration relative to the duration of said first interval in said first expiration.
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Accused Products
Abstract
In a method for controlling an expiratory valve in a ventilator during expiration, the expiratory valve is opened substantially fully for a first interval. Fully opening the expiratory valve has the advantage of minimizing the expiratory resistance a patient needs to overcome. Keeping the expiratory valve open as long as possible during expiration, without losing control of positive end expiratory pressure (PEEP), is therefore advantageous. An optimal system is achieved. In a method wherein pressure in the expiratory section of the ventilator is measured during a second interval, the expiratory valve is regulated so a predetermined end pressure is obtained in the expiratory section, and at least one parameter, directly or indirectly related to control of the expiratory valve, is determined, and a determination is made from that parameter as to whether the next first interval for the next expiration should be longer than, shorter than or as long as the first interval.
98 Citations
9 Claims
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1. A method for controlling an expiratory valve in a ventilator during expiration, said expiratory valve being disposed in an expiratory section of the ventilator, comprising the steps of:
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substantially completely opening said expiratory valve for a first interval, having a duration, in a first expiration;
during a second interval following said first interval in said first expiration, measuring pressure in said expiratory section of said ventilator;
during said second interval, controlling said expiratory valve to produce a predetermined end pressure in said expiratory section;
identifying at least one parameter related to controlling said expiratory valve in said second interval; and
in said second interval, determining from said parameter whether a duration of a first interval in a next-following, second expiration relative to the duration of said first interval in said first expiration. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9)
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5. A method as claimed in claim I comprising identifying a time at which said second interval begins, and using said time as said parameter.
Specification