Adjustment of ventilator pressure-time profile to balance comfort and effectiveness

• US 20040206355A1
• Filed: 05/07/2004
• Published: 10/21/2004
• Est. Priority Date: 03/03/2000
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Berthon-Jones, Michael, Malouf, Gordon, Bateman, Peter
• Granted Patent: US 7,367,337 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3344 Measuring or controlling pressure at the body treatment site

Abstract

The invention is a ventilator whose servo-controller adjusts the degree of support by adjusting the profile of the pressure waveform as well as the pressure modulation amplitude. As the servo-controller increases the degree of support by increasing the pressure modulation amplitude, it also generates a progressively more square, and therefore efficient, pressure waveform; when the servo-controller decreases the degree of support by decreasing the pressure modulation amplitude, it also generates a progressively more smooth and therefore comfortable pressure waveform.

Claims

1-56. -56 (Canceled).

57. A method of controlling a pressure support ventilator comprising the steps of:

supplying breathable gas to a patient'"'"'s airway at a pressure that varies during each respiratory cycle in accordance with an adjustable pressure waveform template having a shape,

determining adequacy of ventilation of the patient, and

automatically making a change to the shape of said pressure waveform template in accordance with the determined adequacy of ventilation, wherein said change produces a decrease in ventilatory support and an increase in comfort when the ventilatory support exceeds that required by the patient.

61. A method of controlling a patient ventilator comprising the steps of:

supplying air to a patient'"'"'s airway at a pressure that varies during each respiratory cycle in accordance with an adjustable pressure waveform template,

repeatedly determining from the supplied airflow adequacy of ventilation of the patient, and

repeatedly changing said adjustable pressure waveform template in accordance with the determined adequacy of ventilation of the patient, wherein the changes control a decrease in ventilation and an increase in comfort when less ventilatory support is required.

65. A method of controlling a pressure support ventilator comprising the steps of:

supplying air to a patient'"'"'s airway at a pressure that varies during each respiratory cycle, the pressure being characterized by both a pressure modulation amplitude and a pressure waveform template,

deriving a measure of instantaneous patient ventilation, and

controlling both said pressure modulation amplitude and the shape of said pressure waveform template in accordance with said measure of instantaneous patient ventilation,

wherein the shape of said pressure waveform template is changed to control a decrease in ventilation and a gain in comfort when less ventilation is required.

67. A pressure support ventilator comprising:

a supply of breathable gas for a patient'"'"'s airway delivered at a pressure that varies during each respiratory cycle in accordance with an adjustable pressure waveform template having a shape,

means for determining adequacy of ventilation of the patient, and

means for automatically making a change in the shape of said pressure waveform template in accordance with the determined adequacy of ventilation, wherein said change produces a decrease in patient ventilatory support and an increase in patient comfort when the ventilatory support exceeds that required by the patient.

71. A patient ventilator comprising:

an air supply for a patient'"'"'s airway delivered at a pressure that varies during each respiratory cycle in accordance with an adjustable pressure waveform template,

means repeatedly determining from the supplied airflow adequacy of ventilation of the patient, and

means for repeatedly changing said adjustable pressure waveform template in accordance with the determined adequacy of ventilation of the patient, wherein the changes control a decrease in ventilation and an increase in comfort when less ventilation is required.

75. A pressure support ventilator comprising:

an air supply for a patient'"'"'s airway delivered at a pressure that varies during each respiratory cycle, the pressure being characterized by both a pressure modulation amplitude and a pressure waveform template,

means for deriving a measure of instantaneous patient ventilation, and

means for controlling both said pressure modulation amplitude and the shape of said pressure waveform template in accordance with said measure of instantaneous patient ventilation,

wherein said controlling means changes the shape of said pressure waveform template to effect a decrease in ventilation and a gain in comfort when less ventilation is required.