The present invention relates to methods and device for buffering anesthetics. More particularly, the invention relates to a needle assembly to be used in conjunction with industrial anesthetic carpule syringes to buffer anesthetic immediately before application of the anesthetic to a patient.
Local anesthetics are the safest and most effective drugs in medicine for the prevention and management of pain during medical and dental procedures. Anesthetics manage the pain by preventing the nociceptive impulse from reaching the brain. In an effort to prolong the shelf life of anesthetics, the anesthetic is often made acidic. Most, if not all, local anesthetic formulations are acidic, with a pH below 7.0 which makes it more shelf stable and result in an extended shelf life. Unfortunately, the acidic nature of typical anesthetics results in discomfort upon injection, delayed effectiveness of the anesthetic, post-injection tissue injury and unreliable effectiveness in the presence of infection and inflammation. All of these drawbacks can be improved with alkalizing anesthetics with buffer solution, such as sodium bicarbonate, to raise the pH to become more neutral prior to injection of the anesthetic.
Lidocaine HCl is one typical local anesthetic that may be chosen by a medical or dental practitioner for use for pain management with a patient. For lidocaine HCl, where the pH is 3.5, 99.99% of the solution is in the charged, or ionized cationic, form which is not lipid soluble. Anesthetic can only cross the nerve membrane when the body converts it to the uncharged, or deionized, free base, form as it approaches a more neutral pH (7.35-7.45). The time that this transformation takes place results in a latency period of the anesthetic. Buffering the acidic anesthetic with, for example, a bicarbonate buffer significantly increases the amount of the active deionized form. Raising the pH from about 3.5 to about 7.4 produces a 6000-fold increase in efficacy. Unfortunately, the addition of the buffering solution cannon be added well prior to the injection use, such as at the factory site or even in the practitioners' office hours or days in advance because of the reduction in shelf life of the product where the efficacy of the medication is significantly reduced at use and the end result if unsatisfactory. Consequently, it is important that a device allows for buffering of the local anesthetic just prior to use.
Syringes are used to deliver many medications, including anesthetic. For example, syringes are used to deliver anesthetic to patients before performing medical or dental work. Many people dislike receiving injections. Receiving injections may cause anxiety and discomfort for the person that extends beyond the pain associated with being pierced by a needle and receiving the injection. Dental and medical practitioners address this patient anxiety and discomfort in a variety of ways. In some instances, practitioners use two different anesthetics. A first anesthetic to numb the area even though the numbing effect may be short lived to the dilating effects of the first anesthetic. The first anesthetic may be used to numb the area sufficiently to allow the practitioner to inject a second anesthetic, which contains the lower pH vasoconstriction, long term anesthetic. However, patients who are afraid of injections generally are even less comfortable with two injections.
Alternately, practitioners may increase the pH of the anesthetic by the addition of buffer solution, such as sodium bicarbonate. Anesthetic is often delivered using disposable carpules placed into a durable syringe. As such, practitioners can increase the pH of the anesthetic by adding buffer solution directly into the anesthetic carpules, generally by injection as described, for example in U.S. Pat. No. 5,603,695. As the anesthetic carpules are manufactured being completely filled, the addition of a buffer solution requires the first removal of some anesthetic and then the subsequent addition of the buffer solution. This is a time-consuming process.
In another alternative approach, as exampled in U.S. Pat. No. 8,162,917, an independent buffering device may be used to deliver buffer solution directly into anesthetic carpules for subsequent use throughout the day with a durable syringe. In this approach, however, the same needle assembly is used to prepare a plurality of anesthetic carpules in the buffering device and thus presents sterility and potential cross-contamination issues. Further, this approach requires the removal of the buffering device (needle assembly and mixing chamber) and the subsequent attachment of a different injection needle for the injection of the buffered anesthetic solution into the patient. Further, this approach requires the anesthetic carpules to be isolated (i.e., not stored within the durable syringe). After the buffering, the anesthetic carpule must be inserted into the durable syringe and then subsequently the addition of an injection needle. This approach is time-consuming and also often results in the buffering of an excess number of carpules, and because buffered anesthetic solution has a limited shelf-life, they are often discarded by the end of the workday.
What is need is a method and device for the buffering of anesthetic, especially anesthetic contained in a syringe carpule, wherein the device provides a needle assembly adapted for dual-functionality of quick, single-patient buffering of anesthetic and also the subsequent injection of the buffered-anesthetic using the same needle assembly.
The present invention is a dual-purpose anesthetic needle device which is intended to be attached to a medical/dental syringe already housing a carpule of local anesthetic, and just prior to use, provide a safe and sterile way to push buffer solution into the local anesthetic carpule. The syringe can then be taken directly to the site of injection. After use, the anesthetic needle device may be disposed of.
An anesthetic needle device may comprise a buffer cartridge for storing and moving a buffer solution into a syringe having an anesthetic carpule; an exhaust cartridge for transferring a buffer solution into a syringe having an anesthetic carpule and also receiving displaced anesthetic from the anesthetic carpule; and a needle assembly for injecting a buffer solution into a syringe having an anesthetic carpule and also injecting a buffered-anesthetic into a patient.
The needle assembly may comprise a transfer needle, said transfer needle being capable of transferring a buffer solution from said buffer cartridge and into the anesthetic carpule; an exhaust needle, said exhaust needle being capable of receiving the anesthetic which was displaced from the anesthetic carpule by the injection of the buffer solution; and a connector, said connector providing structural support for said transfer needle and said exhaust needle and also providing releasable-attachment of said needle assembly to the syringe.
The transfer needle and the exhaust needle may be coaxial to each other. Alternatively, the transfer needle and the exhaust needle may be non-coaxial to each other.
The exhaust cartridge may comprise an exhaust shell, said exhaust shell providing structural support for said exhaust cartridge; and an exhaust housing adapted to form an exhaust chamber for the receiving of anesthetic which was displaced from the anesthetic carpule by the injection of the buffer solution; wherein said transfer needle has a buffer-end and a syringe-end, said buffer-end being in fluid communication with buffer solution stored in the buffer cartridge, said syringe-end being in fluid communication with the anesthetic in the anesthetic carpule; wherein said exhaust needle has a buffer-end and a syringe-end, said buffer-end being in fluid communication with exhaust chamber, said syringe-end being in fluid communication with the anesthetic in the anesthetic carpule.
The buffer cartridge may comprise a plunger for actuating the movement of buffer solution; a plunger stem extending from said plunger; a piston connected to said plunger stem and being adapted to push the buffer solution when actuated by said plunger; and a buffer containment adapted to store the buffer solution and allowing for the movement of the piston.
Plunger markings may be placed on said plunger stem for assisting in the metering of the buffer solution.
The buffer cartridge may further comprise a septum for providing a protective membrane of said buffer containment until such time that said transfer needle is repositioned to pierce said septum for subsequent moving of the buffer solution.
The anesthetic needle device may further comprise a buffer solution stored in the buffer cartridge.
The connector may have threads being adapted for releasable-engagement with the syringe. Alternatively, the connector may be made of a rubber-like material for the force-fit, releasable-engagement with the syringe.
An anesthetic needle device may comprise a buffer cartridge for storing and moving a buffer solution into a syringe having an anesthetic carpule; an exhaust cartridge for transferring a buffer solution into a syringe having an anesthetic carpule and also receiving displaced anesthetic from the anesthetic carpule; a needle assembly for injecting a buffer solution into a syringe having an anesthetic carpule and also injecting a buffered-anesthetic into a patient; and a buffer solution stored in the buffer cartridge.
The needle assembly may comprise a transfer needle, said transfer needle being capable of transferring a buffer solution from said buffer cartridge and into the anesthetic carpule; an exhaust needle, said exhaust needle being capable of receiving the anesthetic which was displaced from the anesthetic carpule by the injection of the buffer solution; and a connector, said connector providing structural support for said transfer needle and said exhaust needle and also providing releasable-attachment of said needle assembly to the syringe.
The transfer needle and the exhaust needle may be coaxial to each other. Alternatively, the transfer needle and the exhaust needle may be non-coaxial to each other.
The exhaust cartridge may comprise an exhaust shell, said exhaust shell providing structural support for said exhaust cartridge; and an exhaust housing adapted to form an exhaust chamber for the receiving of anesthetic which was displaced from the anesthetic carpule by the injection of the buffer solution; wherein said transfer needle has a buffer-end and a syringe-end, said buffer-end being in fluid communication with buffer solution stored in the buffer cartridge, said syringe-end being in fluid communication with the anesthetic in the anesthetic carpule; wherein said exhaust needle has a buffer-end and a syringe-end, said buffer-end being in fluid communication with exhaust chamber, said syringe-end being in fluid communication with the anesthetic in the anesthetic carpule.
The buffer cartridge may comprise a plunger for actuating the movement of buffer solution; a plunger stem extending from said plunger; a piston connected to said plunger stem and being adapted to push the buffer solution when actuated by said plunger; and a buffer containment adapted to store the buffer solution and allowing for the movement of the piston.
The anesthetic needle device is designed for transferring a first solution into a syringe having a carpule containing a second solution and also for injecting a mixture of the first and second solutions into a patient. The device may comprise an exhaust housing providing structural support for said device; an exhaust chamber being formed by said exhaust housing; a transfer needle, having a first-end extending exterior to said exhaust housing and a second-end extending exterior to the exhaust needle, said transfer needle being capable of transferring a first solution into the carpule containing a second solution; an exhaust needle, having a first-end in communication with said exhaust chamber and a second-end extending short of said transfer needle second-end, said exhaust needle being capable of transferring a second solution out of the carpule and into said exhaust chamber; and a connector providing structural support for said transfer needle and said exhaust needle and also providing releasable-attachment of said device to the syringe. The transfer needle and the exhaust needle may be either coaxial or non-coaxial to each other.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as the present invention, it is believed that the invention will be more fully understood from the following description taken in conjunction with the accompanying drawings. Non-limiting and non-exhaustive examples of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. None of the drawings are necessarily to scale.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various examples of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
It will be appreciated that the drawings are illustrative and non-limiting of the scope of the invention which is defined by the appended claims. The examples shown each accomplish various different advantages. It is appreciated that it is not possible to clearly show each element or advantage in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the examples in greater clarity. Similarly, not every example need accomplish all advantages of the present disclosure.
The anesthetic needle device of the present invention provides a dual-purpose injection needle which is intended to be attached to a medical/dental syringe already housing a carpule of the local anesthetic, and just prior to use, provide a timely, safe and sterile pathway to push buffer solution into the local anesthetic cartridge and excess anesthetic solution out, all by the advancement of the buffer solution's plunger. The syringe can then be taken directly to the site of injection.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
For example, one skilled in the art would appreciate that while buffer solution has been described that it may be advantageous to use other solutions for mixing into a carpule of anesthetic. Similarly, one skilled in the art would appreciate that while anesthetic has been described that other materials within a carpule may benefit from the introduction of other solutions.
For example, the exhaust needle and transfer needle may be constructed from sanitary metals, preferably stainless steel, or any other suitable material for the purposes contemplated herein.
For example, the majority of the components of the device may be constructed of a hard plastic or any other suitable material for the purposes contemplated herein.
For example, the present invention was described as being adapted to a durable syringe, likely made from steel tube or rolled metal; that said, the present invention may be adapted to work with any type of syringe generally used in the marketplace.
Number | Date | Country | Kind |
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PCT/US2018/012189 | Jan 2018 | US | national |
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/012189 | 1/3/2018 | WO | 00 |
Number | Date | Country | |
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62441630 | Jan 2017 | US |