Resistance syringe for epidural anesthesia

• US 5,024,662 A
• Filed: 03/13/1990
• Issued: 06/18/1991
• Est. Priority Date: 03/13/1990
• Status: Expired due to Term

• Current Assignee: Cenon M. Menes, Cesar M. Menes
• Original Assignee: Cenon M. Menes, Cesar M. Menes
• Inventors: Menes, Cenon M., Menes, Cesar M.
• Primary Examiner(s): Yasko, John D.
• Application Number:
  US07/492,749
• Time in Patent Office: 462 Days
• Field of Search: 604/131, 604/132, 604/133, 604/218, 604/187, 604/207, 604/208, 604/134, 604/135, 128/DIG. 12, 128/DIG. 13
• US Class Current: 604/131
• CPC Class Codes: A61B 17/3401 Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia local anaesthesia A61M19/00
• CPC Class Codes: A61M 2005/14506 mechanically driven, e.g. spring or clockwork
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

An attachment for a loss of resistance syringe of the type used for inserting a epidural needle into the epidural space of a patient for administration of anesthesia includes an elastomeric band attached between diametrically opposed points of a ring dimensioned to slide onto the barrel and be retained against finger flange on the syringe, the band having a length such that an intermediate portion engaged to a thumb end of the syringe piston will bias the piston for return from a drawn to a depressed position for injecting the syringe contents, the band being characterized in that the bias is insufficient to inject the fluid into tissues normally encountered between the skin and the epidural space of a patient.

Claims

1. A disposable syringe for single handed use in guiding an epidural needle into the epidural space of a patient for administration of anesthesia, comprising:

a disposable syringe including a syringe plunger slidable in a syringe barrel between a normal position and a drawn position for discharging fluid contained in said barrel through said needle;

said barrel being attachable to the hub of an epidural needle;

a band of elastomeric material having two ends secured to said barrel at diametrically opposed points thereof;

said band having a portion intermediate said secured ends stretchable over a thumb end of said plunger for biasing said plunger from said drawn position to said normal position;

wherein discharge of fluid from said barrel through said needle is normally unrestricted thereby to unambiguously signal the penetration of the epidural space by said needle by immediate and easily perceptible plunger movement from said drawn to said normal position under bias of said band as a result of uncontrolled injection of said fluid into the epidural space.

2. The syringe of claim 1 further comprising means for securing an intermediate portion of said band to said thumb end.

3. The syringe of claim 1 wherein said band is secured to a ring slidably fitted onto said barrel against finger flange means provided at one end of said barrel.

4. A disposable syringe for use in inserting an epidural needle into the epidural space of a patient for administration of anesthesia, comprising:

a disposable syringe including a syringe plunger slidable in a syringe barrel between a normal and a drawn position for discharging fluid contained in said barrel through said needle;

said barrel having finger flange means at one and and an opposite end attachable to the hub of an epidural needle;

a band of elastomeric material retained to said barrel adjacent said finger flange means and engageable with a thumb end of said plunger for biasing said plunger from said drawn to said normal position such that said barrel is unrestricted by said band along a major portion of its length between said flange means and said opposite end so that the barrel may be manipulated for guiding said needle through the patient'"'"'s tissues without interference with said bias;

such that the holder of the syringe is alerted to penetration of the epidural space by plunger movement toward said normal position as a result of injection of said fluid into the epidural space under bias of said band.

13. The syringe of claim 4 wherein said band is secured to a ring slidably fitted onto said barrel against finger flange means provided at one end of said barrel.

5. A disposable attachment for a syringe of the type used for inserting an epidural needle into the epidural space of a patient for administration of anesthesia, the syringe having a barrel with finger flange means at one end and an opposite end attachable to the epidural needle, and a plunger movable in said barrel responsive to force applied to a thumb end thereof, said attachment comprising:

a band of elastomeric material having two ends secured to a ring dimensioned to fit onto the barrel of the syringe against said finger flange means, said band having a length such that an intermediate portion engaged to a thumb end of the syringe plunger will bias the plunger for return from a drawn to a normal position for ejecting fluid in the syringe barrel without obstructing manual grasp of said barrel for guidance of said needle toward the epidural space through intervening tissues.

6. The attachment of claim 5 further comprising means for securing an intermediate portion of said band to a thumb end of the syringe plunger.

8. The attachment of claim 6 wherein said means for securing comprise means for adhesively securing said badn to said thumb end.

9. The attachment of claim 6 wherein said means for securing comprise a cap element attachable to said thumb end and means for engaging said intermediate portion to said cap.

10. The attachment of claim 9 wherein said cap element comprises adhesive means for securing said cap element to said thumb end.

7. A kit of parts for use in the administration of epidural anesthesia, comprising:

a disposable syringe including a syringe plunger slidable in a syringe barrel between a drawn and a normal position for discharging the contents of said barrel through said epidural needle;

an epidural needle having a hub attachable to said barrel; and

an elastomeric driver comprising a ring dimensioned to be retained against finger flange means on said barrel, and a band of elastomeric material secured to said ring and to a thumb end of the syringe plunger for biasing the plunger from a drawn to a normal position for ejecting fluid in the syringe barrel;

such that said plunger will remain in said drawn position against said bias so long as said needle traverses tissue overlying the epidural space and will eject the contents of said barrel only upon entering the epidural space, fluid discharge from said barrel through said needle being normally unrestricted to thereby signal proper positioning of said needle in the epidural space by immediate and unambigous movement of said plunger into said barrel.

11. A disposable attachment for a syringe of the type used for inserting an epidural needle into the epidural space of a patient for administration of anesthesia, the syringe having a barrel with finger flange means at one end and an opposite end attachable to the epidural needle, and a plunger displaceable within said barrel under force applied to a thumb end of said plunger, said attachment comprising:

a band of elastomeric material having two ends retained to diametrically opposed points of an element dimensioned to fit onto the barrel of the syringe and be retained against said finger flange means, a cap element having adhesive means for securing said cap element to said thumb end of the plunger, and means securing an intermediate portion of said band to said cap element, so as to bias the plunger for return from a drawn to a normal position for ejecting fluid in the syringe barrel without obstructing manual grasp of said barrel for guidance of said needle toward the epidural space through intervening tissues.

12. A kit of parts for use in the administration of epidural anesthesia, comprising:

a disposable syringe including a syringe plunger slidable in a syringe barrel between a drawn and a normal position for discharging the contents of said barrel through said epidural needle;

an epidural needle having a hub attachable to said barrel; and

an elastomeric driver comprising a ring dimensioned to slidably fit onto the barrel of the syringe and be retained against finger flange means on the syringe, and a band of elastomeric material having two ends retained to diametrically opposed points of said ring, said band having a length such that an intermediate portion engaged to a thumb end of the syringe plunger will bias the plunger for return from a drawn to a normal position for ejecting fluid in the syringe barrel such that grasp of said barrel is unrestricted by said band along a major portion of its length between said flange means and said opposite end so that the barrel may be manipulated for guiding said needle through the patient'"'"'s tissues without interference with said bias;

such that said plunger will remain in said drawn position against said bias while the needle lumen is occluded by tissue overlying the epidural space and will eject the contents of said barrel only upon entering the epidural space thereby signaling proper positioning of said needle in the epidural space by movement of said plunger into said barrel.

14. A method for ascertaining entry of an epidural needle into the epidural space of a patient, comprising the steps of:

providing a disposable syringe including a syringe plunger slidable in a syringe barrel between a drawn and a normal position for discharging the contents of said barrel through said epidural needle;

attaching the hub of an epidural needle to said barrel;

securing an elastomeric element to said syringe barrel and to the thumb end of the syringe plunger so as to bias the plunger for return from a drawn to a normal position for ejecting fluid in the syringe barrel;

drawing said plunger to said drawn position to admit fluid into said barrel;

inserting the lumen of said needle into the patient'"'"'s tissues overlying the epidureal space while holding said plunger in said drawn position against the bias of said elastomeric element; and

releasing said plunger;

manipulating the barrel for guiding said needle lumen into the epidural space;

so that said plunger is held in said drawn position against continuous bias by said elastomeric element so long as the needle lumen traverses tissue overlying the epidural space and will eject the contents of said barrel only upon entering the epidural space thereby signaling proper positioning of said needle lumen in the epidural space by movement of said plunger into said barrel.

15. The method of claim 14 wherein said elastomeric element is secured without obstructing a major portion of the barrel length between said flange means and said opposite end so that the barrel may be manipulated without interference with said bias.

16. The method of claim 14 wherein said step of securing comprises the steps of:

providing an elastomeric element secured to ring means slidable onto said syringe barrel against said finger flange;

sliding said ring means onto said syringe barrel against said finger flange means;

and engaging said elastomeric means with said thumb end of said plunger such that the elastomeric element is stretched between said ring means and said thumb end.

17. The method of claim 15 wherein said fluid drawn into said barrel is air.

18. A method for ascertaining entry of an epidural needle into the epidural space of a patient, comprising the steps of:

providing a syringe including a syringe plunger slidable in a syringe barrel between a drawn and a normal position for discharging the contents of said barrel through said epidural needle;

attaching the hub of an epidural needle to said barrel;

securing an elastomeric element to said syringe barrel and to the thumb end of the syringe plunger so as to bias the plunger for return from a drawn to a normal position for ejecting fluid in the syringe barrel;

drawing said plunger to said drawn position to admit air into said barrel;

inserting the lumen of said needle into the patient'"'"'s tissues overlying the epidureal space while holding said plunger in said drawn position against the bias of said elastomeric element;

releasing said plunger; and

manipulating the barrel for guiding said needle lumen into the epidural space;

so that said plunger is held in said drawn position against continuous bias by said elastomeric element so long as the needle lumen is occluded by tissue overlying the epidural space and will inject the air in said barrel upon entering the epidural space thereby unambiguously signaling proper positioning of said needle lumen in the epidural space by immediately perceptible movement of said plunger into said barrel.