Pressure support ventilation of patients

• US 20030221689A1
• Filed: 12/18/2002
• Published: 12/04/2003
• Est. Priority Date: 07/19/2001
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Berthon-Jones, Michael
• Granted Patent: US 7,520,279 B2
• Time in Patent Office: Days
• US Class Current: 128/204.18
• CPC Class Codes: A61M 16/0057 Pumps therefor
• 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 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)

Abstract

A methodology and apparatus for determining ventilator settings including an end expiratory pressure setting, pressure swing, resistive unloading and target ventilation for delivering ventilatory support based upon generalized patient ventilation characteristics and/or disease classifications. An apparatus may be programmed with the instructions to accomplish the methodology interactively by prompting the user/physician during setup and calculating settings based upon measurements or input responses. Pre-assigned values associated with ventilation characteristics or disease classifications may be combined with a base pressure value or measured values to provide patient customized settings or adjustments to determine pressure levels for the delivery of ventilatory support.

Claims

1. A method for determining a setting for a ventilator to deliver support to a patient to maintain a positive end expiratory pressure comprising the steps of:

selecting an initial pressure value;

prompting for responses to queries about a patient concerning generalized ventilation characteristics; and

calculating a positive end expiratory pressure from said initial pressure value and a set of adjustment pressure values based upon said responses to said queries, said adjustment pressure values representing general ventilation characteristics.

2. An apparatus for determining a setting for a positive end expiratory pressure and then delivering pressure support to a patient in accordance with the setting comprising:

a means for providing controlled pressurized air to a patient;

an input means for accepting data signals;

an output means for displaying queries;

a controller operable to access data from said data signals and generate output through output signals to said output means, said controller with programmed instructions for executing a determination of a positive end expiratory pressure, said instructions controlling the steps of;

prompting for responses to queries about patient ventilation characteristics wherein said ventilation characteristics have assigned pressure values; and

calculating a positive end expiratory pressure from an initial pressure value and said assigned pressure values based upon data from said data signal entered in response to said queries.

3. A method for determining a setting for a ventilator to deliver support to maintain a pressure swing in a specified range chosen to do about half of a patients elastic work comprising the steps of:

selecting an initial pressure value;

prompting for a response to a query about a patient concerning degrees of severity of a restrictive mechanical abnormality of lung or chest wall; and

calculating a pressure swing from said initial pressure value and a set of adjustment pressure values based upon said response to said query,

wherein said set of adjustment pressure values represent degrees of severity of a restrictive mechanical abnormality of lung or chest wall.

4. An apparatus for determining a pressure swing setting for a ventilator and to deliver support at the setting to maintain a specified range chosen to do about half of a patient'"'"'s elastic work comprising:

a means for providing controlled pressurized air to a patient;

an input means for accepting data signals;

an output means for displaying queries;

a controller operable to access data from said data signals and generate output through output signals to said output means, said controller with programmed instructions for executing a determination of a pressure swing, said instructions controlling the steps of;

prompting for responses to queries about degrees of severity of a restrictive mechanical abnormality of lung or chest wall wherein said degrees of severity have assigned adjustment pressure values; and

calculating a pressure swing from a base pressure value and said assigned adjustment pressure values based upon data from said data signal entered in response to said queries.

5. A method for determining a resistive unloading setting for a ventilator to deliver support to unload about 50% to 80% of a subject'"'"'s resistive work comprising the steps of:

prompting for a response to at least one query to determine the subject'"'"'s degree of severity of restrictive disease and obstructive disease; and

setting a resistive unloading value to one of a set of assigned pressure values based upon said response to said at least one query,

wherein said set of assigned pressure values represents degrees of severity of restrictive disease and obstructive disease.

6. An apparatus for determining a resistive unloading setting for a ventilator to deliver support to unload about 50% to 80% of a subject'"'"'s resistive work and for delivering support at the setting comprising:

a means for providing controlled pressurized air to a patient;

an input means for accepting data signals;

an output means for displaying queries;

a controller operable to access data from said data signals and generate output through output signals to said output means, said controller with programmed instructions for executing a determination of a resistive unloading value, said instructions controlling the steps of;

prompting for a response to at least one query about degrees of severity of restrictive disease and obstructive disease wherein said degrees of severity have assigned pressure values; and

setting a resistive unloading value to one of said assigned pressure values based upon said response to said at least one query.

7. A method for determining a target ventilation setting of a ventilator comprising the steps of:

delivering ventilatory support during an awake learning period to a patient;

measuring the patient'"'"'s ventilation over time during a learning period;

measuring the patient'"'"'s partial pressure of CO₂;

calculating a target ventilation as a function of a measure of ventilation; and

adjusting said target ventilation as a function of a measure of partial pressure.

8. An apparatus for determining a target ventilation setting of a ventilator comprising:

a supply means for providing controlled pressurized air to a patient;

a flow means for generating a flow signal representative of patient airflow;

a PCO₂ means for generating a PCO₂ signal representative of a measure of patient partial pressure of CO₂;

a controller operable to (a) access data from the flow signal and the PCO₂ signal, and (b) to control the supply means, said controller with programmed instructions for executing a determination of a target ventilation setting, said instructions controlling the steps of;

delivering ventilatory support during a learning period to a patient;

determining a measure of patient'"'"'s ventilation over time from said learning period;

calculating a target ventilation as a function of the measure of the patient'"'"'s ventilation and as a function of the measure of the partial pressure of CO₂.