Method for use with the pressure triggering of medical ventilators

• US 20070044798A1
• Filed: 08/31/2005
• Published: 03/01/2007
• Est. Priority Date: 08/31/2005
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Levi, Andrew
• Granted Patent: US 7,347,205 B2
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/022 Control means therefor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase

Abstract

A method for providing a pressure reference level for pressure triggering a ventilator responsive to a spontaneous breathing attempt by a patient. In the method, the patient connection of the breathing circuit is capped or plugged. A gas flow is then provided through the breathing circuit and is altered to an amount that causes the flow resistance properties of the breathing circuit to generate a desired gas pressure in the breathing circuit suitable for use as a reference pressure by the ventilator for pressure responsive triggering. During the operation of the ventilator, gas flow in a corresponding amount serves as a bias flow in the breathing circuit to assist breathing by the patient. The bias flow also generates the reference pressure level in the breathing circuit. A reduction in pressure from the pressure level resulting from inhalation by the patient triggers the operation of the ventilator.

Claims

1. A method for providing a reference pressure level for the pressure responsive triggering of a mechanical ventilator to assist a spontaneous breathing effort by a patient, a breathing circuit having a patient connection being interposed between the ventilator and the patient, said method comprising the steps of:

limiting the gas flow properties of the patient connection;

providing a gas flow through the breathing circuits;

sensing the gas pressure generated in the breathing circuit by the gas flow; and

ascertaining when the gas flow is in an amount sufficient to cause the flow resistance properties of the breathing circuit to generate a desired gas pressure in the breathing circuit suitable for use as a reference pressure level for the pressure responsive triggering action, gas flow in a corresponding amount serving as a bias flow in the breathing circuit in the subsequent operation of the ventilator.

2. A method according to claim 1 wherein the gas flow providing step is further defined as:

flowing gas through the breathing circuit; and

altering the gas flow in the breathing circuit to that which attains the desired gas pressure level.

3. A method according to claim 1 wherein the step of limiting the gas flow in the patient connection is further defined as occluding the patient connection.

4. A method according to claim 1 further defined as providing a gas flow in the breathing circuit sufficient to generate a gas pressure less than or equal to a minimum pressure triggering level for operation of the ventilator.

5. A method according to claim 1 further defined as providing a gas flow in the breathing circuit sufficient to generate a gas pressure less than or equal to 0.1 cmH₂O.

6. A method according to claim 1 further including the steps of:

removing the limitation to the gas flow properties in the patient connection after generating the desired gas pressure; and

supplying a bias gas flow from the ventilator in the breathing circuit corresponding to the amount of gas flow that generated the desired gas pressure.

7. A method according to claim 6 wherein a spontaneous breathing attempt by the patient causes a reduction in pressure in the breathing circuit which is used to trigger operation of the ventilator, wherein the method includes the step of sensing the pressure reduction resulting from a spontaneous breathing attempt, and wherein the reference pressure level is used to establish a pressure difference between the reference level and the reduced pressure that is used to trigger operation of the ventilator.