Parameter variation for proportional assist ventilation or proportional positive airway pressure support devices

• US 20010035186A1
• Filed: 03/20/2001
• Published: 11/01/2001
• Est. Priority Date: 03/30/2000
• Status: Active Grant

• Current Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Original Assignee: Respironics Incorporated
• Inventors: Hill, Peter D.
• Granted Patent: US 6,532,956 B2
• Time in Patent Office: Days
• US Class Current: 128/204.18
• 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 16/0069 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 16/101 using an oxygen concentrator
• CPC Class Codes: A61M 16/161 with means for measuring the humidity
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2016/103 the CO2 concentration
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

A system and method for providing a pressure support therapy administered to a patient, where at least one parameter associated with the pressure support therapy is varied according to a time-base parameter variation function. More specifically, at least one parameter or at least one group of parameters associated with a pressure control relation for providing a proportional assist ventilation (PAV) or a proportional positive airway pressure (PPAP) mode of ventilation is varied according to a time-based parameter variation function to control the PAV or PPAP ventilation with a maximum degree of flexibility.

Claims

1. A patient treatment system comprising:

gas flow generating means for providing a flow of breathing gas to an airway of a patient;

pressure controlling means, associated with the gas flow generating means, for controlling a pressure of breathing gas provided to an airway of such a patient;

sensing means for detecting an instantaneous flow rate {dot over (V)} and an instantaneous volume V of the flow of breathing gas provided to such a patient; and

a control unit associated with the sensing means and the pressure controlling means that causes the flow of breathing gas to be provided to such a patient at a pressure in accordance with the following relation;

P_patient=R₁(t){[R₂(t)*(% Set)]*[((R₃(t)*(FA)({dot over (V)}))+(R₄(t)*(VA)(V))]+R₅(t)*EPAP},

where P_patient is the pressure at an airway of such a patient, % Set is a multiplier, FA is a flow assist multiplier, VA is a volume assist multiplier, EPAP is an expiratory positive airway pressure, and R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) are time-based parameter variation functions, and where at least one parameter variation function R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) is a function other than a unity function.

2. A system according to

claim 1

, wherein parameter variation functions R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) are independent of one another.

3. A system according to

claim 1

, wherein the gas flow generating means comprises:

a blower that receives a supply of breathing gas an elevates a pressure of such gas and output a flow of breathing gas;

a patient circuit having a first end coupled to the blower and a second end, wherein the patient circuit carries the flow of breathing gas; and

a patient interface coupled to the second end of the patient circuit to communicate the flow of breathing gas from the patient circuit to an airway of a patient, and wherein the pressure controlling means comprises at least one of;

(a) a control valve coupled to the patient circuit that controls a pressure of flow of breathing gas delivered to a patient by at least one of exhausting gas from the patient circuit and restricting the flow of breathing gas in the patient circuit; and

(b) a variable speed motor coupled to the blower that controls a pressure of the flow of breathing gas delivered to a patient by controlling a rotational velocity of the blower, and, hence, a pressure of the flow of breathing gas output by the blower.

4. A system according to

claim 1

, further comprising an input/output means for setting at least one of the % Set, FA, VA, EPAP, R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t).

5. A system according to

claim 1

, further comprising a memory for storing information regarding at least one of the % Set, FA, VA, EPAP, R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t).

6. A method of treating a patient comprising:

providing a flow of breathing gas to an airway of a patient;

detecting an instantaneous flow rate {dot over (V)} and an instantaneous volume V of the flow of breathing gas provided to such a patient; and

controlling a pressure of breathing gas provided to an airway of such a patient in accordance with the following relation;

P_patient=R₁(t){[R₂(t)*(% Set)]*[((R₃(t)*(FA)({dot over (V)}))+(R₄(t)*(VA)(V))]+R₅(t)*EPAP},

where P_patient is the pressure at an airway of such a patient, % Set is a multiplier, FA is a flow assist multiplier, VA is a volume assist multiplier, EPAP is an expiratory positive airway pressure, and R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) are time-based parameter variation functions, and where at least one parameter variation function R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) is a function other than a unity function.

7. A method according to

claim 6

, further comprising setting parameter variation functions R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) independent of one another.

8. A method according to

claim 6

, wherein providing a flow of breathing gas to an airway of a patient includes:

generating the flow of breathing gas via a blower;

carrying the flow of breathing gas to a patient via a patient circuit having a first end coupled to the blower and a second end; and

communicating the flow of breathing gas to an airway of such a patient via a patient interface coupled to the second end of the patient circuit, and

wherein controlling the pressure of the breathing gas provided to the patient includes least one of;

(a) exhausting gas from the patient circuit,

(b) restricting the flow of breathing gas in the patient circuit, and

(b) controlling a rotational velocity of the blower, and, hence, a pressure of the flow of breathing gas output by the blower.

9. A method according to

claim 6

, further comprising setting at least one of the % Set, FA, VA, EPAP, R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t) using an input/out device.

10. A method according to

claim 6

, further comprising storing in a memory information regarding at least one of the % Set, FA, VA, EPAP, R₁(t), R₂(t), R₃(t), R₄(t), and R₅(t).

11. A patient treatment system comprising:

gas flow generating means for providing a flow of breathing gas to an airway of a patient;

pressure controlling means, associated with the gas flow generating means for controlling a pressure of breathing gas provided to an airway of such a patient;

sensing means adapted to detect an instantaneous flow of gas {dot over (V)} provided to such a patient; and

a control unit associated with the sensing means and the pressure controlling means that causes the flow of breathing gas to be provided to such a patient at a pressure in accordance with a following first relation during at least a portion of a breathing cycle;

P_patient=R₁(t)[R₂(t)Gain*{dot over (V)}+R₃(t)P_base],

where P_patient is the pressure at an airway of such a patient, Gain is a constant, P_base is a base-line pressure, and R₁(t), R₂(t), and R₃(t) are time-based parameter variation functions, and where at least one parameter variation function R₁(t), R₂(t), and R₃(t) is a function other than a unity function.

12. A system according to

claim 11

, wherein parameter variation functions R₁(t), R₂(t), and R₃(t) are independent of one another.

13. A system according to

claim 11

, wherein the gas flow generating means comprises:

a blower that receives a supply of breathing gas an elevates a pressure of such gas and output a flow of breathing gas;

a patient circuit having a first end coupled to the blower and a second end, wherein the patient circuit carries the flow of breathing gas; and

a patient interface coupled to the second end of the patient circuit to communicate the flow of breathing gas from the patient circuit to an airway of a patient, and wherein the pressure controlling means comprises at least one of;

(a) a control valve coupled to the patient circuit that controls a pressure of flow of breathing gas delivered to a patient by at least one of exhausting gas from the patient circuit and restricting the flow of breathing gas in the patient circuit; and

(b) a variable speed motor coupled to the blower that controls a pressure of the flow of breathing gas delivered to a patient by controlling a rotational velocity of the blower, and, hence, a pressure of the flow of breathing gas output by the blower.

14. A system according to

claim 11

, further comprising an input/output means for setting at least one of the Gain, P_base, R₁(t), R₂(t), and R₃(t).

15. A system according to

claim 11

, further comprising a memory for storing information regarding at least one of the Gain, P_base, R₁(t), R₂(t), and R₃(t).

16. A system according to

claim 11

, wherein the control unit controls a pressure of breathing gas delivered to such a patient in accordance with the first relation in combination with a continuous positive airway pressure.

17. A system according to

claim 11

, wherein the control unit controls a pressure of breathing gas delivered to such a patient in accordance with the first relation in combination with a bi-level pressure in which a bi-level base inspiratory positive pressure is greater than a bi-level base expiratory positive airway pressure.

18. A system according to

claim 11

, wherein the control unit controls a pressure of breathing gas delivered to such a patient in accordance with the first relation during an inspiratory phase of a breathing cycle, and in accordance with a following second relation during an expiratory phase of a breathing cycle:

P_patient=R₄(t)[R₅(t)Gain_exp*{dot over (V)}+R₆(t)P_base],

where Gain_exp is a constant and R₄(t), R₅(t), and R₆(t) are time-based parameter variation functions, and wherein at least one parameter variation function R₄(t), R₅(t), and R₆(t) is a function other than a unity function.

19. A system according to

claim 18

, wherein the control unit controls a pressure of breathing gas delivered to such a patient in accordance with at least one of the first relation and the second relation in combination with a bi-level pressure in which a bi-level base inspiratory positive pressure is greater than a bi-level base expiratory positive airway pressure.

20. A system according to

claim 18

, wherein parameter variation functions R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t) are independent of one another.

21. A system according to

claim 18

, further comprising an input/output means for setting at least one of the Gain, Gain_exp, P_base, R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t).

22. A system according to

claim 18

, further comprising a memory for storing information regarding at least one of the Gain, Gain_exp, P_base, R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t).

23. A method of treating a patient comprising:

providing a flow of breathing gas to an airway of a patient;

detecting an instantaneous flow of gas {dot over (V)} provided to such a patient; and

controlling a pressure of breathing gas provided to an airway of such a patient in accordance with a following first relation during at least a portion of a breathing cycle;

P_patient=R₁(t)[R₂(t)Gain*{dot over (V)}+R₃(t)P_base],

where P_patient is the pressure at an airway of such a patient, Gain is a constant, P_base is a base-line pressure, and R₁(t), R₂(t), and R₃(t) are time-based parameter variation functions, and where at least one parameter variation function R₁(t), R₂(t), and R₃(t) is a function other than a unity function.

24. A method according to

claim 23

, further comprising setting parameter variation functions R₁(t), R₂(t), and R₃(t) independent of one another.

25. A method according to

claim 23

, providing a flow of breathing gas to an airway of a patient includes:

generating the flow of breathing gas via a blower;

carrying the flow of breathing gas to a patient via a patient circuit having a first end coupled to the blower and a second end; and

communicating the flow of breathing gas to an airway of such a patient via a patient interface coupled to the second end of the patient circuit, and

wherein controlling the pressure of the breathing gas provided to the patient includes least one of;

(a) exhausting gas from the patient circuit,

(b) restricting the flow of breathing gas in the patient circuit, and

(b) controlling a rotational velocity of the blower, and, hence, a pressure of the flow of breathing gas output by the blower.

26. A method according to

claim 23

, further comprising setting at least one of the Gain, P_base, R₁(t), R₂(t), and R₃(t).

27. A method according to

claim 23

, further comprising storing in a memory information regarding at least one of the Gain, P_base, R₁(t), R₂(t), and R₃(t).

28. A method according to

claim 23

, wherein a pressure of breathing gas provided to an airway of such a patient is controlled in accordance with the first relation in combination with a continuous positive airway pressure.

29. A method according to

claim 23

, wherein a pressure of breathing gas provided to an airway of such a patient is controlled in accordance with the first relation in combination with a bi-level pressure in which a bi-level base inspiratory positive pressure is greater than a bi-level base expiratory positive airway pressure.

30. A method according to

claim 23

, wherein a pressure of breathing gas provided to an airway of such a patient is controlled in accordance with the first relation during an inspiratory phase of the breathing cycle, and in accordance with a following second relation during an expiratory phase of the breathing cycle:

P_patient=R₄(t)[R₅(t)Gain_exp*{dot over (V)}+R₆(t)P_base],

where Gain_exp is a constant and R₄(t), R₅(t), and R₆(t) are time-based parameter variation functions, and where at least one parameter variation function R₄(t), R₅(t), and R₆(t) is also a function other than a unity function.

31. A system according to

claim 30

, wherein a pressure of breathing gas provided to an airway of such a patient is controlled in accordance with at least one of the first relation and the second relation in combination with a bi-level pressure in which a bi-level base inspiratory positive pressure is greater than a bi-level base expiratory positive airway pressure.

32. A method according to

claim 30

, further comprising setting parameter variation functions R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t) are independent of one another.

33. A method according to

claim 30

, further comprising setting at least one of the Gain, Gain_exp, P_base, R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t) using an input/output device.

34. A method according to

claim 30

, further comprising storing in a memory information regarding at least one of the Gain, Gain_exp, P_base, R₁(t), R₂(t), R₃(t), R₄(t), R₅(t), and R₆(t).