Low velocity aortic cannula

• US 5,616,137 A
• Filed: 02/22/1995
• Issued: 04/01/1997
• Est. Priority Date: 02/22/1995
• Status: Expired due to Term

• Current Assignee: Michigan Critical Care Consultants, Inc. (Medtronic Plc)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Lindsay, Erin J.
• Primary Examiner(s): McDermott, Corrine M.
• Assistant Examiner(s): GRING, NOELLE K
• Application Number:
  US08/392,075
• Time in Patent Office: 769 Days
• Field of Search: 604/264, 604/53, 604/9, 604/7, 604/8, 604/19, 604/27, 604/30, 604/93, 604/247, 604/256, 604/280, 604/246
• US Class Current: 604/264
• CPC Class Codes: A61M 2025/0073 Tip designed for influencing the flow or the flow velocity of the fluid, e.g. inserts for twisted or vortex flow
• CPC Class Codes: A61M 25/007 Side holes, e.g. their profiles or arrangements; Provisions to keep side holes unblocked
• CPC Class Codes: A61M 25/06 Body-piercing guide needles or the like

Abstract

An aortic cannula having a distal end adapted to be inserted into the aorta to deliver fluid to the aorta has a flexible tip with a plurality of helical slits that widen and narrow in response to the pressure in the cannula, widening in response to an increase in pressure to reduce exit velocity of the fluid.

Claims

1. An improved aortic cannula having a sidewall with a proximal end and a distal end and a lumen therebetween for conducting fluid, the distal end adapted to be inserted into the aorta to deliver fluid to the aorta, the improvement comprising a plurality of helical slits through the sidewall of the distal end of the cannula that widen and narrow proportionally in response to pressure inside the cannula, widening in response to an increase in pressure to reduce fluid exit velocity.

2. The improved aortic cannula according to claim 1 wherein the slits are oriented at an angle with respect to the radial direction.

3. The improved cannula according to claim 2 wherein the slits are oriented in the opposite direction as the helical turn of the slits, when viewed from the proximal to the distal direction.

4. The improved aortic cannula according to claim 2 wherein the helical slits turn clockwise.

5. The improved aortic cannula according to claim 4 wherein the slits are oriented at an angle with respect to the axial direction.

6. The improved cannula according to claim 5 wherein the slits are oriented in a counter-clockwise direction, when viewed from the proximal to the distal direction.

7. The improved aortic cannula according to claim 1 wherein the slits are oriented at an angle with respect to the axial direction.

8. The improved aortic cannula according to claim 1 wherein the slits extend generally outwardly and distally through the wall of the cannula.

9. The improved aortic cannula according to claim 1 wherein there are at least three slits.

10. The improved aortic cannula according to claim 1 wherein there is an opening through the distal end of the cannula.

11. The improved aortic cannula according to claim 10, wherein the opening through the distal end of the cannula widens in the distal direction.

12. The improved aortic cannula according to claim 1 where there is a diffuser inside the lumen for diverting at least a portion of the flow radially outwardly.

13. The improved aortic cannula according to claim 12 wherein the diffuser is generally conical.

14. The improved aortic cannula according to claim 13 wherein there is an opening through the distal end of the cannula, extending generally axially through the conical diffuser.

15. The improved aortic cannula according to claim 14 wherein the opening in the distal end widens in the distal direction.

16. An aortic cannula having a sidewall with a proximal end and a distal end and a lumen therebetween for conducting fluid, the distal end adapted to be inserted into an aorta to deliver fluid to the aorta, the distal end being closed, except for a plurality of helical slits in the sidewall that widen proportionally to the fluid pressure in the lumen to allow fluid to flow outwardly therethrough, when the pressure inside the lumen is greater than that surrounding the distal end, and which close to block flow into the lumen when the pressure inside the lumen is not greater than that surrounding the distal end.

17. A method of delivering fluid to the aorta of a patient comprising the steps of:

making a slit in the aorta of the patient;

inserting the distal end of a cannula into the aorta through the slit, the cannula having a plurality of helical slits through the sidewall of the distal end of the cannula, circumferentially spaced around the distal end of the cannula;

delivering fluid to the cannula sufficient to cause the distal end of the cannula to turn oppositely from the direction of the helical slits, thereby widening the slots to permit the liquid to flow from the distal end of the cannula through the widened slits.

18. A method of delivering fluid to the aorta of a patient comprising the steps of:

making a slit in the aorta of the patient;

inserting the distal end of a cannula into the aorta through the slit, the cannula having a plurality of helical slits through the sidewall of the distal end of the cannula, circumferentially spaced around the distal end of the cannula; and

delivering fluid to the cannula sufficient to widen the helical slots to permit the liquid to flow from the distal end of the cannula through the widened slits.

19. An aortic cannula having an inner and outer wall with a proximal and distal end and a lumen therebetween for conducting fluid, the distal end adapted to be inserted into an aorta to deliver fluid to the aorta, the distal end having a plurality of helical slits therein through which fluid can exit the cannula and enter the aorta, the slits having a distal bias extending distally from the inner wall of the cannula to the outer wall of the cannula to impart a distal bias to the fluid that flows through the slits of the cannula.

20. The aortic cannula according to claims 19 wherein the slits have a distal bias such that in longitudinal cross-section the slit extends radially and distally from the inner wall of the cannula to the outer wall of the cannula to impart a distal bias to the fluid that flows through the slits of the cannula.

21. A method of delivering fluid to the aorta of a patient comprising the steps of:

making a slit in the aorta of the patient;

inserting the distal end of a cannula into the aorta through the slit, the cannula having a plurality of helical slits therein which have a distal bias; and

delivering fluid to the cannula to create a distally-biased flow from the slits into the aorta.