Needle shield converting to a needleless needle

Details Needle shield converting to a needleless needle Needle shield converting to a needleless needle

2001-08-07

2004-02-03

Mendez, Manuel (Department: 3763)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

Reexamination Certificate

active

06685677

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a needle assembly capable of withdrawing medicine from a vial, injecting into a port in a patient, and preventing accidental punctures or “sticks” from a contaminated needle. In particular, the invention relates to a needle assembly including a sharp hollow needle for penetrating a septum of a vial. The needle assembly also includes a blunt cannula for injecting into an injection port. The blunt cannula concentrically surrounds the sharp hollow needle, forms a liquid-tight seal with the cannula, and retractably extends relative to the sharp hollow needle.
2. Description of the Related Art
The spread of contagious blood-born diseases such as HIV and Hepatitis has provided incentive for many to invent syringes with safety devices to prevent people from accidentally sticking themselves or others with contaminated needles. These safety syringes have not become accepted because they are too difficult to use or too expensive.
As stated, many needle safety shield devices have been devised to reduce the risk of inadvertent needle punctures. Many of these devices are designed to slide over a used needle to a position where the needle is completely encased permanently so that an inadvertent needle puncture would be eliminated.
There are also needles called “Needleless needles” or “blunt plastic cannulas” that are needle substitutes. These blunt plastic cannulas are similar to needles in shape but are plastic and have a blunt end. They are only able to gain access into the body by way of a pre-slit injection port connected to a catheter. The injection port is designed specifically for receiving blunt plastic cannulas. These blunt plastic cannulas have a tremendous advantage over the conventional steel needles. Once the blunt plastic cannula is locked in place on the syringe, the fear of a possible contaminated needle stick is eliminated; the blunt plastic cannula cannot pierce the skin and only can gain access into the body through the pre-slit injection recepticle.
However, blunt plastic cannulas cannot pierce the rubber septums used to seal medicine vials. Therefore, a syringe having only a plastic blunt cannula cannot withdraw medicine from a vial through a rubber septum.
Another problem with some of the Needle safety shield devices (where the needle is permanently encased by an outer connecting structure) is that although the user can shield a used contaminate needle, a moment still exists where the sharp used needle is exposed. In this moment, a contaminated needle puncture can occur. Furthermore, the moment when the syringe is first removed is the most dangerous moment for accidental needle sticks caused by an uncooperative or convulsing patient.
Syringes with exchangeable blunt cannulas and sharp needles exist. A clean sharp needle is initially attached to a syringe. The sharp needle can pierce the rubber septum of a medicine vial for withdrawal of the medicine. Once filled, the still uncontaminated sharp needle is removed and a blunt plastic cannula is screwed onto the syringe. The patient is injected with the syringe and blunt cannula by using a pre-slit injection port. The now contaminated blunt plastic cannula is unable to pierce the caregiver's skin.
Although, the syringe with exchangeable tips appears to provide a solution, in practice, most health care workers have chosen not to use these syringes because they are too time consuming to use. When a nurse withdraws an intravenous solution from a vial, which must be accessed by a steel needle, rarely will the nurse, who is pushed for time, stop and change the steel needle and find a blunt plastic cannula with which to replace it. Again, this makes a contaminated needle strike possible.
Buttgen et al. (U.S. Pat. No. 6,015,396) disclose an Automatic Cannula Withdrawing Device for Injection Syringes. The syringe withdraws into a housing as the injection is completed. The housing shields the used needle and prevents unintended sticks. The housing does not form a cannula that can inject into a septum. Furthermore, if the volume held in the syringe is not fully injected, the needle is not retracted and unintentional sticks can occur.
Alexander (U.S. Pat. No. 5,993,418) discloses a Safety Syringe. In Alexander, the syringe includes a needle surrounded by fluid-tight barrel. The needle extends beyond the barrel and allows the needle to penetrate a vial and the skin of a patient. When the plunger is fully compressed, a lever causes the needle to retract within the barrel. The barrel of the safety syringe is not a cannula that can allow injections through pre-slit injection port. If the plunger is not fully compressed, the needle does not withdraw into the barrel. So, a used needle still can stick an injector.
Caizza (U.S. Pat. No. 5,755,696) discloses a Syringe Filling and Delivery Device. The syringe includes a needle and a coaxial cannula surrounding the needle. Springs urge the needle within the cannula. Pressing harder than the springs to extend the needle through the septum fills the syringe. During injection the cannula penetrates a rubber septum without extending the needle. No lock is included in Caizza. So, under enough force, such as an accident, a used needle can extend beyond the cannula and stick the injector.
Kraus et al. (U.S. Pat. No. 5,704,919) disclose an Intravenous Cannula Assembly. The assembly is for inserting a catheter intravenously. Once inserted, fluids can be injected or withdrawn through the assembly. The assembly includes a coaxial needle and cannula. Initially, the needle extends longer than the cannula. The extended needle pierces a patient's skin and vein. The needle is then withdrawn into a telescoping sleeve for disposal leaving a connected cannula. Separate tubing is then connected to the cannula. The Assembly is not a syringe. Because the needle is removed from the back of the assembly (where the volume of liquid to be injected would be in a syringe), the device cannot be adapted to a syringe.
Haber et al. (U.S. Pat. No. 4,950,250) disclose a Collapsible Needle Cover. The cover folds to expose a needle. The needle is exposed during injection and withdrawal of fluid from a vial. The unfolded cover prevents unintended sticks when extended. The cover is not able to act as a cannula through which injections take place.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a needle assembly capable of withdrawing medicine from a vial having a rubber septum and injecting the medicine into a port in a patient while not endangering the care giver with an accidental stick with a contaminated used needle.
With the foregoing and other objects in view there is provided, in accordance with the invention, a needle assembly. The needle assembly includes a sharp hollow needle for penetrating a septum of a vial. The needle assembly also includes a blunt cannula for injecting into an injection port. The blunt cannula concentrically surrounds the sharp hollow needle and forms a liquid-tight seal with the needle. The blunt cannula retractably extends relative to the sharp hollow needle. By extending beyond the needle, the blunt cannula can be used to inject medicine into a port in a patient. However, this blunt cannula acts as a shield over the sharp needle, so, once the blunt cannula has been deployed, the sharp needle cannot penetrate a caregiver's skin.
In accordance with a further feature of the invention, the needle assembly includes a syringe connected longitudinally to the blunt cannula.
In accordance with a further feature of the invention, the needle assembly includes a wing having an upper wing element and a lower wing element joined by a hinge. The wing is fixed proximally to the sharp hollow needle and unfolds at the hinge to extend the blunt cannula beyond said sharp hollow needle.
In accordance with a further feature of the invention, the wing includes a lock preventing the wing from unfolding once the wing has been unfolded.
In accordance with a further feature of the invention, the wi

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