Dual mode negative pressure source operation for provision of negative pressure wound therapy

Patent metadata

Field	Value
Publication number	US-12226566-B2
Application number	US-202117919700-A
Country	US
Kind code	B2
Filing date	Apr 23, 2021
Priority date	Apr 23, 2020
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A negative pressure source can be fluidically connected to the wound dressing, the wound dressing can be positioned to cover at least a portion of the wound, and the negative pressure source can be controlled to supply negative pressure to the wound via the fluid flow path. An actuator of the negative pressure source can be controlled to operate in a dual mode by transitioning between a proportional-integral (PI) control or proportional-integral-derivative (PID) control and a pulsed control. Stalling of the actuator can be prevented, and therapy can be provided without interruptions.

First claim

What is claimed is:

1. A negative pressure wound therapy device comprising:
a source of negative pressure configured to be connected via a fluid flow path to a wound covered by a wound dressing, the source of negative pressure configured to supply negative pressure to the wound via the fluid flow path;
a pressure sensor configured to measure pressure in the fluid flow path; and
a controller configured to control the source of negative pressure, the controller further configured to:
determine a pressure difference between a negative pressure setpoint corresponding to desired negative pressure at the wound and pressure measured by the pressure sensor;
in response to determining that the pressure difference does not satisfy a stall threshold of a motor of the source of negative pressure, apply to the motor a first drive signal determined based on the pressure difference; and
in response to determining that the pressure difference satisfies the stall threshold of the motor, apply a second drive signal to the motor and cause the motor to be activated for a first period of time and deactivated for a second period of time subsequent to the first period of time.

2. The negative pressure wound therapy device of claim 1 , wherein the first drive signal causes the motor to operate in accordance with at least one of a proportional integral (PI) control or proportional integral derivative (PID) control.

3. The negative pressure wound therapy device of claim 2 , wherein the second drive signal causes the motor to operate in accordance with pulsed control.

4. The negative pressure wound therapy device of claim 1 , wherein the first drive signal causes the motor to be activated for a duration of the first drive signal.

5. A negative pressure wound therapy device comprising:
a source of negative pressure configured to be connected via a fluid flow path to a wound covered by a wound dressing, the source of negative pressure configured to supply negative pressure to the wound via the fluid flow path;
a pressure sensor configured to measure pressure in the fluid flow path; and
a controller configured to control the source of negative pressure, the controller further configured to:
responsive to a determination that a pressure difference between a desired level of negative pressure at the wound and pressure measured by the pressure sensor does not satisfy a stall threshold of a motor of the source of negative pressure, actuate the motor according to a proportional integral (PI) control or proportional integral derivative (PID) control; and
responsive to a determination that the pressure difference satisfies the stall threshold of the motor, actuate the motor according to a pulsed control.

6. The negative pressure wound therapy device of claim 5 , wherein the stall threshold of the motor corresponds to a voltage or current level causing the motor to stall.

7. The negative pressure wound therapy device of claim 5 , wherein pulsed control comprises alternating periods of activation and deactivation of the motor.

8. A negative pressure wound therapy device comprising:
a source of negative pressure configured to be connected via a fluid flow path to a wound covered by a wound dressing, the source of negative pressure configured to supply negative pressure to the wound via the fluid flow path;
a pressure sensor configured to monitor a pressure in the fluid flow path; and
a controller configured to control the source of negative pressure, the controller further configured to:
apply a first drive signal to an actuator of the source of negative pressure to cause the source of negative pressure to supply negative pressure to the wound via the fluid flow path;
adjust the first drive signal applied to the actuator based on a difference between the pressure in the fluid flow path and a negative pressure setpoint; and
responsive to a determination that a flow in the fluid flow path satisfies a flow threshold indicative of a stalling of the actuator, apply a second drive signal different from the first drive signal to the actuator and cause the actuator to continue operating to establish or maintain the negative pressure setpoint at the wound.

9. The negative pressure wound therapy device of claim 8 , wherein the controller is configured to adjust the first drive signal to minimize the difference between the pressure in the fluid flow path and the negative pressure setpoint.

10. The negative pressure wound therapy device of claim 8 , wherein the controller is further configured to determine that the flow threshold is satisfied responsive to the difference satisfying a pressure difference threshold.

11. The negative pressure wound therapy device of claim 8 , wherein the controller is configured to iteratively adjust the first drive signal.

12. The negative pressure wound therapy device of claim 8 , wherein the controller is further configured to:
responsive to a determination that the pressure in the fluid flow path is smaller than a pressure threshold, cease applying the second drive signal and apply the first drive signal to the actuator.

13. The negative pressure wound therapy device of claim 8 , wherein the controller is further configured to cease applying the second drive signal and apply the first drive signal responsive to a determination that the flow threshold is no longer satisfied.

14. The negative pressure wound therapy device of claim 8 , wherein the controller is further configured to:
responsive to a determination that the pressure in the fluid flow path does not satisfy the negative pressure setpoint, continue to adjust the first drive signal based on the difference.

15. The negative pressure wound therapy device of claim 8 , wherein the first drive signal causes the actuator to operate in accordance with at least one of a proportional integral (PI) control or proportional integral derivative (PID) control.

16. The negative pressure wound therapy device of claim 15 , wherein the second drive signal causes the actuator to operate in accordance with pulsed control that alternates periods of activation and deactivation of the actuator.

17. The negative pressure wound therapy device of claim 8 , wherein the actuator comprises a motor.

18. The negative pressure wound therapy device of claim 8 , wherein the controller is configured to apply the second drive signal at a power level that is less than maximum power level of the actuator.

19. The negative pressure wound therapy device of claim 8 , wherein the actuator comprises a motor, and wherein application of the first drive signal responsive to the determination that the flow in the fluid flow path satisfies the flow threshold would cause the motor to stall.

20. The negative pressure wound therapy device of claim 1 , wherein application of the first drive signal in response to determining that the pressure difference satisfies the stall threshold would cause the motor to stall.

21. The negative pressure wound therapy device of claim 5 , wherein actuation of the motor responsive to the determination that the pressure difference satisfies the stall threshold of the motor would cause the motor to stall.

Assignees

• Smith & Nephew

Inventors

• Askem Ben Alan
• Elder David Michael

Classifications

• A61M1/918

  for multiple suction locations · CPC title

• A61M2205/3344

  Measuring or controlling pressure at the body treatment site · CPC title

• A61M1/75 Primary

  Intermittent or pulsating suction (A61M1/63, A61M1/772 take precedence) · CPC title

• A61M2205/3317

  Electromagnetic, inductive or dielectric measuring means · CPC title

• A61M1/966 Primary

  having a pressure sensor on or near the dressing · CPC title