Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
2001-02-22
2003-08-05
Metjahic, Safet (Department: 2171)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C206S438000, C206S459100
Reexamination Certificate
active
06603318
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sealed package that permits verification of conditions within the package and/or functionality of components sealed within the package without unsealing the package. Also, the present invention relates to a method for determining conditions within the package and/or functionality of components sealed within the package without unsealing the package.
2. Description of the Prior Art
Many products are sealed in packages for various reasons. Examples of reasons for sealing products in a package can include maintaining sterility of the products, preventing contact of the products with air, and for protection during shipping, among others. For any one or more of these reasons, it may be desired to maintain a certain atmosphere within a sealed package. Along these lines, it may be desired to maintain temperature, gas composition, humidity and temperature, among other variables, within certain ranges.
Maintaining products at certain conditions may be preferable or necessary to maintain functionality of the products. Of course, once a package is opened, the conditions within the package are no longer the same as within the sealed package, unless the exact conditions within the package are known and duplicated in the external environment that the package is opened in. Also, over time conditions within a package can change, resulting in changes to the product(s) sealed within. If the conditions that a product is stored in affect its functionality, it may be desired to discard or refresh products that may no longer be functional due to storage conditions and/or the length of the storage period.
According to one particular example, it is typically desired to maintain products in a sterile environment. It may also be desirable and/or necessary to maintain medical products in a certain atmosphere to maintain the functionality or optimal functionality of the products. Opening a package that contains a medical device compromises the sterility of the device. Therefore, it can be particularly difficult to determine the status of a medical device since opening the package compromises the sterility of the device.
To ensure that medical devices in particular are suitable for use, a destruction policy may include discarding all devices with a certain age. This may be necessary due to the inability to know the qualities of a device. Such a destruction policy may result in discarding and thereby wasting viable devices.
For example, electrode pads may include a hydrogel that facilitates their operation. The shelf life of electrode pads is determined in part by the length of time it takes for enough water moisture to evaporate out of the hydrogel and escape the pads package. As moisture escapes, the electrical properties of the electrode pads may become increasingly compromised.
In one context, where electrode pads are utilized with a defibrillator, a very significant factor includes changes in small and large signal impedance values between a patient and a defibrillator. As the hydrogel dries out, the impedance values increase, making it more difficult to monitor a patient's electrical signals, obtain transthoracic impedance, and deliver energy into the body.
Water loss can affect the mechanical properties of the hydrogel as well. In some hydrogels, the loss of water causes the hydrogel to skin over or solidity, especially around the edges, which destroys the ability of the hydrogel to adhere to the skin. This partial or complete loss of adhesion can render an electrode useless since it cannot then create or maintain an effective contact with the skin. Thus, the drying of the electrode pad can prevent or attenuate receipt of electrocardiogram (ECG) signals by a defibrillator and can alter the delivery of defibrillation energy to the patient.
Additionally, poor or uneven contact of the electrode pad with a patient's skin may unduly concentrate energy transfer during defibrillation into areas that exhibit good skin contact. Higher than usual current densities that result from poor or uneven skin contact can cause skin bums. If the current is not delivered by the defibrillator to a patient in the manner that an electrode pad was designed for, the resulting treatment delivered to the patient may be altered.
To help ensure that electrode pads will be usable when opened, electrode manufacturers currently print an expiration date on each set of pads. The electrode pads are to be discarded no later than the expiration date. However, the expiration date typically is determined based upon studies of the hydrogel used on the pads, and the amount of water moisture that escapes the package over time under normal as well as strenuous conditions. A safety factor is added to give time for the electrode pads to be shipped from the supplier to an original equipment manufacturer (OEM), and then from the OEM to the customer. This helps to ensure that the electrode pads are always usable, barring any package damage, when removed from the package before the expiration date.
Calculating the expiration date of electrode pads or other components as described above is a conservative method of ensuring quality. However, as a result, the expiration date may arrive before the pads have actually expired. In fact, electrode pads may be usable for much longer than the expiration date, especially if they are kept at room temperature or in a high humidity environment.
While electrode pads or other components may naturally over time become nonfunctional, at other times an electrode package may be damaged in some way. For example, tiny punctures or slits in the package which may be too small to be seen by the casual observer or with the naked eye, or tears in the metal packaging layer caused by bonding the package, can allow water moisture to escape. Without noticing damage to the electrode pads' package, a customer typically will not replace electrode pads until the expiration date arrives, when in fact the hydrogel on those pads may be dry and unusable long before.
The above example only represents one particular example of an electrode pad of a particular use. Electrode pads for other uses may be similarly affected. Also, devices other than electrode pads may be affected by age and package conditions. Furthermore, factors other than humidity can affect the functionality of a device.
SUMMARY OF THE INVENTION
The present invention addresses problems related to ensuring operability of packaged devices. The present invention may be useful with a variety of products affected by a variety of conditions in their package. One advantage of the present invention is that the functionality of a device or component may be measured directly or indirectly while the device or component is still sealed in its package.
As such, the present invention relates to a sealed package for a component. The package includes at least two package portions. Determining elements within the sealed package permit determination of at least one parameter including at least one ambient condition within the package. An indicator operatively connected to the determining elements indicates the functionality of the component within the sealed package.
The present invention also relates to a method for determining functionality of a component in a sealed package. According to the method, at least one ambient condition within the package. It is then determined whether the parameter corresponds to an acceptable value at which the component functions. Next, it is indicated whether the parameter corresponds to an acceptable operational value for the component.
Still other objects and advantages of the present invention will become readily apparent by those skilled in the art from a review of the following detailed description. The detailed description shows and describes preferred embodiments of the invention, simply by way of illustration of the best mode contemplated of carrying out the present invention. As will be realized, the invention is capable of other and different e
Hansen Kim J.
Solosko Thomas A.
Koninklijke Philips Electronics , N.V.
LeRoux Etienne P
Metjahic Safet
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