Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-11-09
2003-06-10
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
Reexamination Certificate
active
06575941
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a device that protects against accidental contact with or puncture by sharp instruments. More particularly, it relates to an arrangement that protects against contact with and puncture by sharp medical instruments, such as, for example, hypodermic, blood-collection, and other needles.
BACKGROUND OF THE INVENTION
In recent years, there has been increasing concern among both health practitioners and the general public regarding the danger of transmission of toxic medications, microorganisms, and other dangerous pathogens through accidental puncture by sharp medical instruments, such as hypodermic and blood-collection needles. Modern medical techniques are often invasive and health practitioners routinely use a variety of venipuncture devices. Danger arises if a patient is injected with an instrument that has not been kept properly sterile, and it can also arise if there is accidental puncture of an individual by the instrument after it has been exposed to fluids such as infected blood.
In the past, a number of devices have been proposed that offer some level of protection to patients and health practitioners against such dangers. For any such device, there are several characteristics that should be achieved for the device to be considered successful. The design should be such that the safety device is convenient to use and minimizes the potential for inadvertent contact with the instrument both before and after use of the instrument. This is preferably achieved with a device that requires only a single hand to close the protective cover. The safety device should not interfere with use of the instrument itself, and the device should be both simple and convenient for the practitioner to use without danger that the practitioner will puncture himself or herself, and without danger that the practitioner will touch and contaminate the instrument. It is also desirable that it be possible for such a device to be made at low cost, especially when the devices are to be mass-produced.
Such protection devices have generally taken the form of some kind of safety guard that prevents contact with the sharp object when the instrument is not in use, and includes some mechanism by which the guard can be removed when the instrument is to be used. For such designs, the safety guard should be fastened to the instrument in a secure manner so that it is resistant to accidental breakage or dislodgement. It is also advantageous that there be a mechanism by which any excess fluid can discharge from the device after the safety guard is replaced. Other desirable characteristics are that the design of the device be such that it can be used with a variety of medical instruments and can be manufactured inexpensively.
U.S. Pat. No. 4,867,746 discloses a device having a safety portion connected to the instrument with a flexible body that obscures the view of the practitioner during operation of the instrument. This device is useful only for low-angle insertions into a patient's skin, because the protective portion of the device can only be moved as far as permitted by the flexibility of the body. Moreover, this device offers minimal, if any, protection against contamination of the instrument prior to its use. Further, there is a significant danger of accidental breakage of the safety device if the flexible body is displaced by too great an amount in an effort to use the instrument for a larger-angle insertion.
Danger of accidental breakage is also present in the device disclosed in U.S. Pat. No. 3,658,061, which comprises a slotted flexible plastic sleeve that snaps over the entire length of the instrument with a rotational action. The force required to lock the mechanism during this rotational operation may lead to accidental breakage. Moreover, the device appears unsuitable for adaptation to types of instruments other than hypodermic needles because of its characteristic shape.
U.S. Pat. No. 4,664,259 discloses a device having a cover attached to the device by a hinge, but the locking mechanism is configured so that some torque must be applied to the cover to release it. Because such protective covers are often constructed of polymeric material, a design that requires the application of torque is inherently inferior since a practitioner may inadvertently apply too great a torque to the small plastic device and break it. An alternative embodiment of the device disclosed in U.S. Pat. No. 4,664,259 involves a butterfly type of device wherein the cover is divided into two halves that separate individually. This is similar to the device presented in U.S. Pat. No. 4,820,277, which also uses a butterfly type of design. These designs do not permit easy single-handed replacement of the cover.
Another hinged device is disclosed in U.S. Pat. No. 5,188,611 (“the '611 patent”). In this design, the protective device comprises a slotted longitudinal member that swings over the sharp end of the instrument. This longitudinal member is attached to a collar with a flexible hinge; the collar engages the body of the instrument. The device may include two locking mechanisms. The primary locking mechanism consists of a partial sleeve in the longitudinal member that fits snugly over a hub. An alternative to this locking mechanism is shown in
FIG. 4
of this application, wherein a pair of snap catches is used to hold the protective cover in place. The secondary locking mechanism comprises a keeper shelf that is positioned to block movement of the needle in the direction of the slot in the longitudinal member. This functions as a locking mechanism by prohibiting the needle from escaping the protective cover, but it will be readily appreciated that disengagement of this form of a locking device requires the application of either transverse or torsional forces on the protective device in order to release the instrument from the protective device. None of the different embodiments for the primary locking mechanism is designed specifically to resist the application of such torsional forces and the design is therefore susceptible to breakage.
Another disadvantage of the device described in the '611 patent and depicted in
FIG. 4
is that, in preparing for making an injection, when the protective cover is opened by unlocking the protective cover from the snap catches to unshield the injection needle, accidental puncture may occur. Specifically, since the most convenient way to open the protective cover is to use one hand to hold the instrument and to use a finger of the other hand to push the top of the protective cover to swing it open. During this process, the sharp end of the needle is in proximity with and in the movement path of the finger pushing the protective cover to swing it open; this exposes the finger to a risk of accidental puncture. It is desirable that the risk of such accidental puncture be eliminated or reduced.
An additional device of the hinged type is described in U.S. Pat. No. 5,669,889 (“the '889 patent”). The device described there includes a permanent locking mechanism so that the protective cover cannot be removed after it is positioned over the sharp instrument. While the existence of a permanent locking mechanism ensures that the device cannot be reused after the protective cover has been positioned, there are numerous deficiencies with the design described there. Since the permanent locking mechanism is the only mechanism that can be used to hold the protective cover in place, the protective cover cannot be used to protect against puncture by the sharp instrument before it is used. Instead, it is necessary to include an additional separate protective sheath that covers the instrument before it is used. This additional protective sheath not only adds cost to the device but also requires separate disposal. Additionally, the existence of this sheath requires that the hinged protective cover be askew as shown in
FIG. 1
of the '889 patent, making bulk packing inefficient.
The design described in the '889 patent also contemplates the us
Lam Ann Y.
Nguyen Anhtuan T.
Safety Medical Supply International, Inc.
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