Thermal Management Algorithm For Phacoemulsification System

• US 20110137232A1
• Filed: 12/09/2009
• Published: 06/09/2011
• Est. Priority Date: 12/09/2009
• Status: Active Grant

• Current Assignee: Alcon Research, LLC (Alcon Incorporated)
• Original Assignee: Alcon Research Limited (Nestle SA)
• Inventors: BASSINGER, KENNETH D., SALEHI, AHMAD, BOUKHNY, MIKHAIL, TEODORESCU, DAN, MORGAN, MICHAEL D.
• Granted Patent: US 8,070,711 B2
• Time in Patent Office: Days
• US Class Current: 604/22
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/320084 Irrigation sleeves
• CPC Class Codes: A61F 9/00745 using mechanical vibrations, e.g. ultrasonic
• CPC Class Codes: A61M 1/772 operating alternately
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2210/0612 Eyes

Abstract

A control system for managing power supplied to a phacoemulsification hand piece includes a power source that provides power to the hand piece and a controller that controls the power source. The controller calculates a thermal value based on irrigation fluid flow and a power level and decreases the power level in proportion to the calculated thermal value when the calculated thermal value exceeds a threshold thermal value. Irrigation fluid flow can be calculated from irrigation fluid pressure.

Claims

1. A control system for managing power supplied to a phacoemulsification hand piece, the control system comprising:

an irrigation pressure sensor for measuring an irrigation pressure;

a power source for providing ultrasonic power to the hand piece; and

a controller for controlling the power source;

wherein the controller calculates a thermal value based on the irrigation pressure and a power level and decreases the power level in proportion to the calculated thermal value when the calculated thermal value exceeds a threshold thermal value.

2. The control system of claim 1 wherein the calculated thermal value is an input to the controller.

3. The control system of claim 1 wherein the controller operates so that the power level tracks an inverse of a segment of the calculated thermal value that exceeds the threshold thermal value.

4. The control system of claim 1 wherein the controller decreases the power level smoothly.

5. The control system of claim 1 wherein the controller calculates the thermal value further based on a value representing friction between an irrigation sleeve and a phacoemulsification needle.

6. The control system of claim 1 wherein controller further compares the calculated thermal value to the threshold thermal value.

7. The control system of claim 1 wherein when the controller decreases the power level in proportion to the calculated thermal value, the controller overrides surgeon control of the power source.

8. The control system of claim 1 wherein when the controller decreases the power level in proportion to the calculated thermal value, the controller does not decrease the power level to zero.

9. The control system of claim 1 wherein the power source provides pulsed power to the hand piece and when the controller decreases the power level in proportion to the calculated thermal value, the controller decreases the amplitude of a pulse.

10. The control system of claim 1 wherein surgeon control of the power source is resumed when the calculated thermal value is less than the threshold thermal value.

11. A control system for managing power supplied to a phacoemulsification hand piece, the control system comprising:

a power source for providing power to the hand piece; and

a controller for controlling the power source;

wherein the controller calculates a thermal value based on irrigation fluid flow and a power level and decreases the power level in proportion to the calculated thermal value when the calculated thermal value exceeds a threshold thermal value.

12. The control system of claim 11 wherein the calculated thermal value is an input to the controller.

13. The control system of claim 11 wherein the controller operates so that the power level tracks an inverse of a segment of the calculated thermal value that exceeds the threshold thermal value.

14. The control system of claim 11 wherein the controller decreases the power level smoothly.

15. The control system of claim 11 wherein the controller calculates the thermal value further based on a value that represents friction between an irrigation sleeve and a phacoemulsification needle.

16. The control system of claim 11 wherein controller further compares the calculated thermal value to the threshold thermal value.

17. The control system of claim 11 further comprising:

an irrigation pressure sensor that measures an irrigation pressure used by the controller to calculate the irrigation fluid flow.

18. The control system of claim 11 wherein when the controller decreases the power level in proportion to the calculated thermal value, the controller overrides surgeon control of the power source.

19. The control system of claim 11 wherein when the controller decreases the power level in proportion to the calculated thermal value, the controller does not decrease the power level to zero.

20. The control system of claim 11 wherein the power source provides pulsed power to the hand piece and when the controller decreases the power level in proportion to the calculated thermal value, the controller decreases the amplitude of a pulse.

21. The control system of claim 11 wherein surgeon control of the power source is resumed when the calculated thermal value is less than the threshold thermal value.