Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-12-21
2003-11-18
Thanh, LoAn H. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
Reexamination Certificate
active
06648858
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to syringes for medical use. More particularly, the present invention pertains to safety devices for prefilled injection syringes. The present invention is particularly, but not exclusively, useful for safely removing the sheath from a syringe and thereafter providing a passive guard assembly that is configured to allow for injections at relatively large angles from the normal at the injection site.
BACKGROUND OF THE INVENTION
Recent research from the Centers for Disease Control and Prevention (CDC) shows that approximately 384,000 needlesticks or similar injuries occur among health care workers in U.S. hospitals each year. Unfortunately, each accidental needlestick has the potential to expose a health care worker to a life-threatening virus such as hepatitis or HIV. In addition to the needlesticks that occur in hospitals, accidental needlesticks can also occur in other health care settings. For example, needlestick injuries can occur at clinics or during home health care. In fact, some studies have estimated that over 600,000 needlesticks occur in the U.S. each year, and approximately 1,000 of these accidental needlesticks result in a life-threatening infection.
For each accidental needlestick, health care providers are obligated to test and counsel the exposed worker. Further, follow-up testing for HIV must be conducted approximately six months after the exposure. It is to be appreciated that the costs associated with the testing, lab work, the workers lost time, and the associated tracking and administrative costs, can be considerable.
Accidental needlesticks can occur in several ways. For example, a sudden movement by the patient can cause a health care worker to lose control of a syringe, resulting in injury. Attempts to manually recap a needle after filling the syringe with a medicament or attempts to recap a syringe following an injection can also result in injury. Moreover, injuries often result when contaminated, unprotected needles are left unattended or disposed of improperly. In addition to accidental needlesticks, unnecessary exposure to bloodborne pathogens can result when a health care worker mistakenly reuses a contaminated needle on a patient.
Prefilled injection syringes (i.e. syringes that are delivered to the health care worker containing a single dose of medicament) are commonly used for vaccines, low molecular weight heparins and many new biotechnology drugs. By using a prefilled injection syringe, several needle handling steps are eliminated for the health care worker, and the risk of inadvertent re-use is lowered. Even with these advantages, the risk of exposure to a used needle is still presented by prefilled injection syringes. As such, a safety device that passively covers and protects the needle of a prefilled injection syringe after an injection is desirable. More specifically, a safety device that can be easily installed is needed to allow the large amount of existing prefilled syringes to be used safely.
Heretofore, prefilled syringes have generally been delivered to the user with a sheath installed over the needle to protect the needle during transportation and handling. Some currently available safety devices require the user to remove the sheath manually before installing a passive safety guard. A safer alternative is to provide a passive safety guard that can be installed before removal of the sheath. For this type of installation, the passive guard system is generally sized to fit over the sheath. Unfortunately, passive guard devices having a large diameter distal tip (i.e. large enough to fit over the needle sheath) often jam during an injection, especially when the syringe is used to perform an injection at a non-normal angle to the injection surface.
In light of the above, it is an object of the present invention to provide a passive guard system for installation over a sheathed, prefilled injection syringe that safely removes the sheath and subsequently allows for injections at relatively large angles from the normal at the injection site. It is another object of the present invention to provide a safety device for a sheathed prefilled injection syringe which allows the safety device to be installed on the syringe while the needle remains sheathed yet does not jam during injections at large angles from the normal at the injection site. It is yet another object of the present invention to provide a safety device that is installable on a sheathed prefilled injection syringe that passively covers the needle after an injection, locking a portion of the guard assembly over the tip of the needle to prevent accidental needlesticks or inadvertent reuse of the syringe. Yet another object of the present invention is to provide a safety device for a sheathed prefilled injection syringe that is easy to use, relatively simple to implement, and comparatively cost effective.
SUMMARY OF THE PREFERRED EMBODIMENTS
The present invention is directed to a safety device for use in conjunction with a sheathed, prefilled injection syringe during an injection. In operational overview, the safety device is first installed onto the sheathed, prefilled injection syringe. With the safety device installed on the syringe, a portion of the safety device (a cover) is removed. The removal of the cover performs two separate functions. First, removal of the cover removes the sheath from the syringe, exposing the syringe needle. Second, as detailed further below, removal of the cover reconfigures a passive guard assembly in the safety device into a configuration that is suitable for an injection. During an injection, a portion of the passive guard assembly is allowed to translate relative to the injection needle. This relative movement allows for needle penetration into the patient to the proper depth during an injection. Upon withdrawal of the needle from the patient, this relative movement allows the guard assembly to passively re-cover the needle, locking a portion of the guard assembly over the tip of the needle to prevent accidental needlesticks or inadvertent reuse of the syringe.
In greater structural detail, the passive guard assembly of the safety device includes a guard, a housing and a coil spring. For the present invention, a portion of the housing is preferably formed as an elongated, hollow cylinder that is large enough to slide over the syringe barrel of the prefilled injection syringe allowing attachment of the proximal end of the housing to the finger guard of the syringe. Like the housing, the guard is preferably formed as an elongated, hollow cylinder and defines a longitudinal axis. The proximal end of the cylindrical guard is sized for insertion into the distal end of the housing. With this combination of structure, the housing is disposed over the guard allowing both axial and rotational movement between the guard and housing. Additionally, a biasing mechanism, such as a spring, is mounted between the guard and the housing to urge the guard in a distal direction, relative to the housing. A plug formed on the guard interacts with a channel formed in the housing to control relative movement between the guard and the housing during an injection.
Importantly for the present invention, the guard extends to a distal tip that is formed with a dilatable opening. Functionally, the distal portion of the guard is reconfigurable between a first configuration in which the opening is relatively large and a second configuration in which the opening is relatively small. With the distal portion of the guard in the first configuration, the relatively large opening allows the sheathed needle of the injection syringe to pass through the end of the guard during attachment of the safety device to the syringe. On the other hand, in the second configuration, the relatively small opening allows for syringe injections at relatively large angles from the normal at the injection site.
Structurally, to create the dilatable opening, the distal portion of the guard is formed having a shape that is similar to the shape
Nydegger & Associates
Thanh LoAn H.
Visual Connections, Inc.
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