Occlusion detector for dual-port surgical tourniquet systems

• US 20060224181A1
• Filed: 03/31/2005
• Published: 10/05/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Western Clinical Engineering Ltd.
• Original Assignee: Western Clinical Engineering Ltd.
• Inventors: McEwen, James A., Jameson, Michael
• Granted Patent: US 7,771,453 B2
• Time in Patent Office: Days
• US Class Current: 606/202
• CPC Class Codes: A61B 17/1355 Automated control means therefor

Abstract

A occlusion detector for a dual-port surgical tourniquet system comprises: a tourniquet cuff for encircling a patient'"'"'s limb and including an inflatable portion that communicates pneumatically with a first cuff port and that communicates pneumatically with a second cuff port independently of the first cuff port; a tourniquet instrument that is releasably connectable to the first and second cuff ports to establish first and second pneumatic passageways between the tourniquet cuff and the tourniquet instrument, wherein the tourniquet instrument includes pressure sensing means communicating with the first pneumatic passageway for producing an indication of the pressure in the cuff over a time period suitably long for the performance of a surgical procedure, pressure regulation means communicating with the second pneumatic passageway for regulating the pressure in the cuff near a reference pressure level, and an occlusion detector for introducing a pneumatic pressure pulse into the first pneumatic passageway during an occlusion detection time period, for monitoring the pressure in the second pneumatic passageway during the occlusion detection time period, and for producing an occlusion alarm if a fluctuation of pressure in the second pneumatic passageway is not detected within the occlusion detection time period.

Claims

1. An occlusion detector for a dual-port surgical tourniquet system, comprising:

a tourniquet cuff for encircling a patient'"'"'s limb and including an inflatable portion that communicates pneumatically with a first cuff port and that communicates pneumatically with a second cuff port independently of the first cuff port;

a tourniquet instrument that is releasably connectable to the first and second cuff ports to establish first and second pneumatic passageways between the tourniquet cuff and the tourniquet instrument, wherein the tourniquet instrument includes

pressure sensing means communicating with the first pneumatic passageway for producing an indication of the pressure in the cuff over a time period suitably long for the performance of a surgical procedure,

pressure regulation means communicating with the second pneumatic passageway for regulating the pressure in the cuff near a reference pressure level, and

an occlusion detector for introducing a pneumatic pressure pulse into the first pneumatic passageway during an occlusion detection time period, for monitoring the pressure in the second pneumatic passageway during the occlusion detection time period, and for producing an occlusion alarm if a fluctuation of pressure in the second pneumatic passageway is not detected within the occlusion detection time period.

2. The apparatus as defined in claim 1 wherein the occlusion detector further suspends the operation of the pressure regulation means during the occlusion detection time period.

3. The apparatus as defined in claim 1 wherein the occlusion detector sets the level of the pressure pulse to a level that differs from the reference pressure level by at least a predetermined difference pressure for a period of time less than the occlusion detection time period.

4. The apparatus as defined in claim 3 wherein the level of the pressure pulse is set to a level greater than the reference pressure level.

5. The apparatus as defined in claim 3 wherein the level of the pressure pulse is set to a level less than the reference pressure level.

6. The apparatus as defined in claim 3 wherein the occlusion detector further sets the level of the pressure pulse introduced into the first pneumatic passageway to a level that causes the fluctuation of pressure detected in the second pneumatic passageway to be greater than a predetermined minimum pressure fluctuation level.

7. The apparatus as defined in claim 1 wherein the tourniquet instrument is responsive to a physiologic signal indicative of a physiologic characteristic of the patient and wherein the tourniquet instrument further includes means for adapting the reference level in response to the level of the physiologic signal.

8. The apparatus as defined in claim 1 wherein the tourniquet cuff has a predetermined cuff width at the location of the first cuff port, and wherein the first cuff port is formed of flexible material and has a first port length that is greater than the cuff width at the location.

9. The apparatus as defined in claim 8 wherein the cuff is formed of materials that can be sterilized by techniques normally used to sterilize medical devices.

10. A dual-port surgical tourniquet system having an occlusion detector, comprising:

a tourniquet cuff for encircling a patient'"'"'s limb and including an inflatable portion that communicates pneumatically with a first cuff port and that communicates pneumatically with a second cuff port independently of the first cuff port;

a tourniquet instrument that is releasably connectable to the first and second cuff ports to establish first and second pneumatic passageways between the tourniquet cuff and the tourniquet instrument, wherein the tourniquet instrument includes

pressure sensing means for producing an indication of the pressure in the inflatable portion of the cuff,

pressurizing means for pressurizing the cuff,

pressure relief means for depressurizing the cuff,

pressure regulation means responsive to the pressure sensing means for selectably activating the pressurizing means and the pressure relief means to regulate the pressure in the cuff near a reference pressure level during a time period suitably long for the performance of a surgical procedure; and

an occlusion detector for suspending the regulation of the pressure in the cuff by the pressure regulation means during an occlusion detection time period, for introducing a pressure pulse into the first passageway during the occlusion detection time period, for monitoring the pressure in the second passageway during the occlusion detection time period, and for producing an occlusion alarm if a fluctuation of pressure in the second passageway is not detected within the occlusion detection time period.

11. The apparatus as defined in claim 10 wherein the pressure pulse differs from the reference pressure level by at least a predetermined difference pressure for a period of time less than the occlusion detection time period.

12. The apparatus as defined in claim 10 wherein the pressurizing means communicates pneumatically with the first pneumatic passageway, wherein the pressure relief means communicates pneumatically with the second pneumatic passageway, and wherein the occlusion detector activates the pressurizing means to introduce the pressure pulse at a predetermined pressure level that is greater than the reference pressure level.

13. The apparatus as defined in claim 10 wherein the pressurize relief means communicates pneumatically with the first pneumatic passageway, wherein the pressurizing means communicates pneumatically with the second pneumatic passageway, and wherein the occlusion detector activates the pressure relief means to introduce the pressure pulse at a predetermined pressure level that is less than the reference pressure level.

14. An occlusion detector for a dual-port surgical tourniquet cuff, comprising:

a tourniquet cuff having an inflatable portion and adapted for encircling a patient'"'"'s limb and being pressurized to a reference pressure level sufficient to stop arterial blood flow into the limb past the encircling cuff to facilitate the performance of a surgical procedure, wherein the inflatable portion communicates pneumatically with a first cuff port and a second cuff port; and

an occlusion detector releasably connectable to the first cuff port for introducing a pneumatic pressure pulse into the first cuff port during an occlusion detection time period and releasably connectable to the second cuff port for monitoring the pressure at the second cuff port during the occlusion detection time period, and wherein the occlusion detector produces an occlusion alarm if a fluctuation of pressure at the second cuff port is not detected within the occlusion detection time period.

15. The apparatus as defined in claim 14 and including tourniquet pressure regulating means communicating pneumatically with the first and second cuff ports for regulating the pressure in the tourniquet cuff near the reference pressure level, wherein the occlusion detector further suspends the regulation of the pressure by the pressure regulation means for the occlusion detection time period.

16. The apparatus as defined in claim 14 wherein the pressure pulse differs from the reference pressure level by at least a predetermined difference pressure for a period of time less than the occlusion detection time period.

17. An occlusion detector for a dual-port surgical tourniquet system comprising:

pulse introduction means for introducing a pneumatic pressure pulse into a first port of a dual-port tourniquet cuff during each of a plurality of occlusion detection time periods; and

detection means for monitoring the pressure at the second port of the dual-port tourniquet cuff during each of the plurality of occlusion detection time periods, and for producing an occlusion alarm if a fluctuation of pressure at the second port is not detected within each of the plurality of occlusion detection time periods.

18. The apparatus as defined in claim 17 and including a dual-port tourniquet cuff having the first and second cuff ports and a tourniquet instrument releasably connectable to the first and second cuff ports of the tourniquet cuff to establish first and second pneumatic passageways between the tourniquet cuff and the tourniquet instrument, wherein the tourniquet instrument includes pressure regulation means operable for regulating the pressure of gas in the connected cuff near a reference pressure level, wherein the tourniquet instrument suspends the operation of the pressure regulation means during each of the plurality of occlusion detection time periods, and wherein the tourniquet instrument further suspends the operation of the pressure regulation means in response to the production of an occlusion alarm by the occlusion detector.

19. A method for detecting an occlusion in a dual-port surgical tourniquet cuff comprising the steps of

introducing a pneumatic pressure pulse into a first cuff port communicating pneumatically with an inflatable portion of a tourniquet cuff during an occlusion detection time period,

monitoring during the occlusion detection time period the pressure at a second cuff port communicating pneumatically with the inflatable portion of the tourniquet cuff independently of the first cuff port, and

producing an occlusion alarm if a fluctuation of pressure within the second cuff port is not detected within the occlusion detection time period.

20. The method of claim 19 and including the step of suspending any regulation of the pressure in the inflatable portion of the tourniquet cuff by a tourniquet instrument for the duration of the occlusion detection time period.