Breathing apparatus and method

• US 6,622,726 B1
• Filed: 10/17/2000
• Issued: 09/23/2003
• Est. Priority Date: 10/17/2000
• Status: Expired due to Term

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Newport Medical Instruments Incorporated (Medtronic Plc)
• Inventors: Du, Hong-Lin
• Primary Examiner(s): Lo, Weilun
• Assistant Examiner(s): MENDOZA, MICHAEL G
• Application Number:
  US09/690,970
• Time in Patent Office: 1,071 Days
• Field of Search: 128/204.21, 128/204.23, 128/204.26, 128/205.11, 128/205.14, 128/205.24, 128/207.12, 128/207.14, 128/207.18
• US Class Current: 128/204.26
• 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 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 2230/46 Resistance or compliance of the lungs

Abstract

A positive airway pressure assist breathing apparatus or ventilator system has a gas delivery unit, an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a, patient during an inspiratory phase of each breath, and an expiratory unit for controlling exhausting of gases from the patient during an expiratory phase of each breath. A pressure sensor senses gas pressure in the system, and a control unit controls pressure of gas supplied to a patient in each inspiratory phase based on a pre-set target pressure. The control unit is arranged to calculate a boost pressure level periodically according to a determined patient breathlessness level, and to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level higher than the pre-set target pressure, and to reduce the pressure back to the pre-set target pressure at a predetermined time after the start of the inspiratory phase and prior to the end of the inspiratory phase. Boost pressure is adjusted periodically based on each new determination of the patient breathlessness level.

Claims

1. A breathing apparatus to provide positive airway pressure assist, comprising:

a gas delivery unit having an input for connection to a source of breathing gas and an output;

an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a patient during an inspiratory phase of each breath;

an expiratory unit for controlling exhaling of gases from the patient during an expiratory phase of each breath;

an expiratory line having an output connected to the expiratory unit and an input for connection to a patient;

sensor means for sensing a parameter associated with patient breathlessness;

a control unit connected to the gas delivery unit, expiratory unit, and sensor means for controlling pressure of gas supplied to a patient during each inspiratory phase and controlling exhalation of gas from the patient during each expiratory phase, the pressure of gas supplied during each inspiratory phase being based on a pre-set target pressure;

the control unit including program means for periodically determining a level of patient breathlessness based on the output-of the sensor means,.means for using the determined patient breathlessness level to calculate a boost-pressure level higher than the;

pre-set target pressure, means for operating the control unit to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level in order to reduce patient breathlessness, and means for reducing the boost pressure of gas supplied to the patient back to the pre-set target pressure at a predetermined time after the start of each inspiratory phase and prior to the end of the inspiratory phase.

2. The apparatus as claimed in claim 1, wherein the means for determining the level of patient breathlessness comprises means for measuring patient airway occlusion pressure at periodic intervals, and for increasing the boost pressure level in response to increase in patient airway occlusion pressure.

3. The apparatus as claimed in claim 1, wherein the program includes means for operating the control unit to taper the pressure supplied to the patient from the boost pressure level back to the pre-set target pressure at approximately the Middle of the inspiratory phase of each breath.

4. A positive airway pressure breathing system, comprising:

a gas delivery unit having an input for connection to a source of breathing gas and an output;

an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a patient during an inspiratory phase of each breath;

an expiratory unit for controlling exhaling of gases from the patient during an expiratory phase of each breath;

an expiratory line having an output connected to the expiratory unit and an input for connection to a patient;

a pressure sensor for sensing pressure in the system;

a control unit connected to the gas delivery unit, expiratory unit, and pressure sensor for controlling pressure of gas supplied to a patient in each inspiratory phase and exhaling of gas from the patient during each expiratory phase, the pressure of gas during each inspiratory phase being based on a pre-set target pressure;

a user input device connected to the control unit for user input of a selected breathless sensation assist level; and

a program associated with the control unit for operating the control unit, the program comprising means for periodically determining the degree of patient breathlessness from the pressure sensor output, means for calculating a boost pressure level higher than the pre-set target pressure, the boost pressure level being a function of the determined degree of patient breathlessness and the user selected breathless sensation assist level, and means for operating the control unit to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level to reduce patient breathlessness, and to reduce the pressure of gas supplied to the patient back to the pre-set target pressure at a predetermined time after the start of the inspiratory phase and prior to the end of the inspiratory phase.

5. The apparatus as claimed in claim 4, wherein the program further comprises means for detecting a user input breathless sensation assist level of zero, and for operating the control unit to supply gas at the pre-set target pressure for the entire inspiratory phase on detection of a zero input at the user input device.

6. A breathing apparatus for providing positive airway pressure assistance, comprising:

a gas delivery unit having an input for connection to a source of breathing gas and an output;

an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a patient during an inspiratory phase of each breath;

an expiratory unit for controlling exhaling of gases from the patient during an expiratory phase of each breath;

an expiratory line having an output connected to the expiratory unit and an input for connection to a patient;

a pressure sensor for sensing pressure in the system;

a control unit connected to the gas delivery unit, expiratory unit, and pressure sensor for controlling supply of gas to a patient in each inspiratory phase and exhaling of gas from the patient during each expiratory phase, the supply of gas during each inspiratory phase being based on a pre-set target pressure;

a user input device connected to the control unit for user input of a selected breathless sensation assist level; and

a program associated with the control unit for operating the control unit, the program comprising means for determining the level of patient breathlessness at predetermined intervals by measuring patient airway occlusion pressure, means for calculating a boost pressure level higher than the pre-set target pressure based on the user input breathless sensation assist level and the determined level of patient breathlessness, means for operating the control unit to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level in order to reduced patient breathlessness, and to reduce the pressure of gas supplied to the patient back to the pre-set target pressure at a predetermined time after the start of the inspiratory phase and prior to the end of the inspiratory phase.

7. The apparatus as claimed in claim 6, wherein the program includes means for calculating airway resistance, and means for varying the boost pressure level as a function of the user selected breathless sensation assist level, the measured patient airway occlusion pressure, and the calculated airway resistance.

8. A method of controlling the inspiratory phase in a positive pressure assist breathing system in order to relieve patient breathlessness, comprising the steps of:

setting a target pressure for pressure of gas supplied to the patient during the inspiratory phase;

determining a boost pressure of gas to be supplied to the patient which is higher than the pre-set target pressure;

periodically determining the level of patient breathlessness and adjusting the boost pressure in response to changes in the level of patient breathlessness;

boosting the pressure of gas supplied to the patient to the most recently determined boost pressure at the start of each inspiratory phase in order to relieve any breathless sensation encountered by the patient; and

gradually reducing the pressure of gas supplied to the patient from the boost pressure back to the pre-set target pressure at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase.

9. The method as claimed in claim 8, wherein the step of determining an initial boost pressure comprises monitoring a breathless sensation assist (BSA) level entered by a user at a control device and varying the boost pressure based on the entered BSA level.

10. The method as claimed in claim 9, wherein no boost is added to the pre-set level of gas supplied to the patient if the user selected BSA level is zero.

11. The method as claimed in claim 8, wherein the step of periodically determining the level of patient breathlessness comprises measuring the patient airway occlusion pressure at a predetermined point in inspiration and adjusting the boost pressure to be used for the next inspiratory phase in response to any change in patient breathlessness level.

12. The method as claimed in claim 9, including the step of calculating the patient airway resistance and increasing the boost level in response to increase in patient airway resistance.

13. The method as claimed in claim 9, wherein the step of determining a boost level comprises determining a boost pressure level higher than the set target pressure level, the step of boosting the level of gas comprises monitoring the pressure in the system with a pressure sensor, and boosting the pressure until the predetermined boost pressure level is reached, and the step of reducing the level of gas supplied to the patient comprises reducing the pressure from the boost pressure level back to the set target pressure level.

14. A method of controlling the inspiratory phase in a pressure targeted ventilation system, comprising the steps of:

setting a target pressure level for the inspiratory phase;

determining a boost level of gas to be supplied to the patient which is higher than the pre-set target pressure level;

boosting the pressure of gas supplied to the patient to the determined level higher than the pre-set target level at the start of the inspiratory phase in order to relieve any breathless sensation encountered by the patient;

gradually reducing the pressure of gas supplied to the patient from the boost pressure back to the pre-set target pressure at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase;

the step of determining a boost level comprising monitoring a breathless sensation assist (BSA) level entered by a user at a control device and varying the boost level based on the entered BSA level, and further comprising periodically determining the patient airway occlusion pressure at a predetermined point in inspiration and increasing the boost level in response to an increase in patient airway occlusion pressure; and

the patient airway occlusion pressure being measured at predetermined intervals, each patient airway occlusion pressure measurement being taken at approximately 0.1 seconds after the start of a patient inspiratory effort.

15. The method as claimed in claim 14, wherein the patient airway occlusion pressure is measured at intervals corresponding to a predetermined number of breaths.

16. A method of controlling the inspiratory phase in a pressure targeted ventilation system, comprising the steps of:

setting a target pressure level for the inspiratory phase;

determining a boost level of gas to be supplied to the patient which is higher than the pre-set target pressure level;

boosting the pressure of gas supplied to the patient to the determined boost level higher than the pre-set target level at the start of the inspiratory phase in order to relieve any breathless sensation encountered by the patient;

gradually reducing the pressure of gas-supplied to the patient from the boost pressure back to the pre-set target pressure at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase;

the step of determining a boost level comprising monitoring a breathless sensation assist (BSA) level entered by a user at a control device and varying the boost level based on the entered BSA level, and further comprising periodically determining the patient airway occlusion pressure at a predetermined point in inspiration and increasing the boost level in response to an increase in patient airway occlusion pressure; and

the patient airway occlusion pressure being measured at predetermined intervals, each patient airway occlusion pressure measurement being taken at a predetermined time interval after the start of a patient inspiratory effort.

17. A method of controlling the inspiratory phase in a pressure targeted ventilation system, comprising the steps of:

setting a target pressure level for the inspiratory phase;

determining a boost level of gas to be supplied to the patient which is higher than the pre-set target pressure level;

boosting the pressure of gas supplied to the patient to the determined boost level higher than the pre-set target level at the start of each inspiratory phase in order to relieve any breathless sensation encountered by the patient;

gradually reducing the pressure of gas supplied to the patient from the boost pressure level back to the pre-set target pressure level at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase;

the step of determining a boost pressure level comprising monitoring a breathless sensation assist (BSA) level entered by a user at a control device and varying the boost pressure level based on the entered BSA level, and further comprising periodically determining the degree of patient breathlessness at a predetermined point in inspiration and adjusting the boost pressure level in response to a change in the determined degree of patient breathlessness; and

the degree of patient breathlessness being measured at a predetermined intervals after the start of a patient inspiratory effort.

18. A pressure targeted ventilation system, comprising:

a gas delivery unit having an input for connection to a source of breathing gas and an output;

an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a patient during an inspiratory phase of each breath;

a pressure controller for controlling the pressure of gas supplied to a patient during each inspiratory phase;

an expiratory unit for controlling exhaling of gases from a patient during an expiratory phase of each breath;

a user input device connected to the pressure controller for user input of a selected breathless sensation assist (BSA) level;

sensor means connected to the pressure controller for sensing the level of patient breathlessness during an inspiratory phase;

the pressure controller including means for setting a target pressure level for the inspiratory phase, means for determining a boost level of gas to be supplied to the patient which is higher than the pre-set target pressure level, means for boosting the pressure of gas supplied to the patient to the determined boost pressure level higher than the pre-set target level at the start of each inspiratory phase in order to relieve any breathless sensation encountered by the patient, and means for gradually reducing the pressure of gas supplied to the patient from the boost pressure back to the pre-set target pressure at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase;

the means for determining a boost level comprising means for monitoring the breathless sensation assist (BSA) level entered by a user at the user input device and varying the boost level based on the entered BSA level, and further comprising means for periodically determining the patient breathlessness level at a predetermined point in inspiration and increasing the boost pressure level in response to an increase in the determined patient breathlessness level; and

the means for determining patient breathlessness level comprising means for measuring a parameter which is a function of patient breathlessness at predetermined intervals, each measurement being taken at a predetermined time interval after the start of a patient inspiratory effort.

19. A pressure targeted ventilation system, comprising:

a gas delivery unit having an input for connection to a source of breathing gas and an output;

an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a patient during an inspiratory phase of each breath;

a pressure controller for controlling the pressure of gas supplied to a patient during each inspiratory phase;

an expiratory unit for controlling exhaling of gases from a patient during an expiratory phase of each breath;

a user input device connected to the pressure controller for user input of a selected breathless sensation assist (BSA) level;

a pressure sensor for sensing pressure in the system;

the pressure controller including means for setting a target pressure level for the inspiratory phase, means for determining a boost level of gas to be supplied to the patient which is higher than the pre-set target pressure level, means for boosting the pressure of gas supplied to the patient to the determined boost pressure level higher than the pre-set target level at the start of each inspiratory phase in order to relieve any breathless sensation encountered by the patient, and means for gradually reducing the pressure of gas supplied to the patient from the boost pressure back to the pre-set target pressure at a predetermined point in the inspiratory phase prior to the end of the inspiratory phase;

the means for determining a boost level comprising means for monitoring the breathless sensation assist (BSA) level entered by a user at the user input device and varying the boost level based on the entered BSA level, and further comprising means for periodically determining the patient airway resistance and adjusting the boost pressure level in response to a change in the patient airway resistance.