Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-09-14
2001-07-03
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S044000, C604S180000, C604S244000, C600S347000, C206S365000
Reexamination Certificate
active
06254586
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to improved sensor placement and infusion devices and, in particular embodiments, to devices and methods for placing a sensor set at a selected insertion site within the body of a user, which has the capability to remove fluid buildups and/or deliver selected fluids to the selected insertion site. The invention further relates to methods for delivering a fluid to the selected insertion site, and to kits for carrying out the delivery methods.
BACKGROUND OF THE INVENTION
Over the years, a variety of implantable electrochemical sensors have been developed for detecting and/or quantifying specific agents or compositions in a patient's blood. For instance, glucose sensors have been developed for use in obtaining an indication of blood glucose levels in a diabetic patient. Such readings can be especially useful in monitoring and/or adjusting a treatment regimen which typically includes the regular administration of insulin to the patient. Thus, blood glucose readings are particularly useful in improving medical therapies with semi-automated medication infusion pumps of the external type, as generally described in U.S. Pat. Nos. 4,562,751; 4,678,408; and 4,685,903; or automated implantable medication infusion pumps, as generally described in U.S. Pat. No. 4,573,994, which are herein incorporated by reference.
Generally, small and flexible electrochemical sensors can be used to obtain periodic readings over an extended period of time. In one form, flexible subcutaneous sensors are constructed in accordance with thin film mask techniques in which an elongated sensor includes thin film conductive elements encased between flexible insulative layers of polyimide sheets or similar material. Such thin film sensors typically include a plurality of exposed electrodes at one end for subcutaneous placement with a user's blood, or the like, and a corresponding exposed plurality of conductive contacts at another end for convenient external electrical connection with a suitable monitoring device. Typical thin film sensors are described in commonly assigned U.S. Pat. Nos. 5,390,671; 5,391,250; 5,482,473; and 5,586,553 which are incorporated by reference herein. See also U.S. Pat. No. 5,299,571.
Drawbacks to conventional implantable sensors arise from the initial subcutaneous insertion and from the extended presence of the sensor at the subcutaneous insertion site. For example, the area surrounding the implantable sensor may swell or fill with fluid that impedes the ability of the implantable sensor to provide accurate results. This represents a potential health hazard, since less accurate information could lead to erroneous dosing of medication or the like. Another drawback that results from a sensor being inserted for extended periods of time is that it is more prone to infection, which is a health hazard and can also result in fluid buildup and inaccurate readings. To overcome these drawbacks of inaccurate readings and the possibility of infection, the implantable sensor is removed from the subcutaneous site and a new implantable sensor is inserted at a different subcutaneous insertion site. While this solution does provide more accurate readings or reduces the occurrence of infections, it is expensive due to the increased number of implantable sensors needed, and is painful for the user who must insert implantable sensors in more locations and on a more frequent basis.
In addition to addressing problems of fluid buildup at a subcutaneous insertion site, it would be beneficial to supply a fluid to the site. In particular, it would be useful to supply fluids including antibiotics, anti-inflammatory agents or healing agents to the insertion site. It would also be beneficial to supply a calibration solution to a sensor at the insertion site, to enable sensor calibration in situ and thus obviate the need for frequent removal of the implanted sensor.
A need exists for a method of delivering a fluid to an insertion site, in particular a sensor insertion site. There is also a need for a kit including elements that are useful in carrying out the improved method.
SUMMARY OF THE DISCLOSURE
In accordance with one aspect of the present invention, there is provided a method of supplying a fluid to a placement site. According to the inventive method, a sensor set is first mounted onto a skin of a user, and a placement site is contacted with the sensor set. The sensor set includes a base to secure the sensor set to the skin of the user; a cannula coupled to and extending from the base; an insertion device operatively coupled to the sensor set and the cannula to facilitate insertion of the cannula to contact the placement site; an externally extending conduit; and a sensor. The cannula has at least one lumen with an end for fluid communication with the placement site, and also has at least one port formed near another end of the lumen opposite the end for fluid communication. The conduit is in fluid communication with the at least one port of the cannula. The sensor has a sensor portion exposed by the at least one port in the at least one lumen of the cannula to determine a body characteristic of the user at the placement site.
After the sensor set is mounted on the user's skin, a fluid is introduced through the externally extending conduit and the lumen to the placement site.
In a preferred embodiment, the fluid is supplied periodically in a predetermined amount, more specifically from an external pump device. Alternatively, the fluid is supplied from a disposable source.
Preferred fluids for delivery to the placement site include an ingredient such as a healing agent, an antibiotic, an anti-inflammatory agent, a cleaning agent, a sensor recharging agent, an insulin, an insulin analog, saline or glucose. According to a specific preferred embodiment, the fluid is a calibration solution having a known level of the body characteristic of the user. More particularly, the body characteristic is the glucose level in a bodily fluid (e.g., blood or interstitial fluid) of the user, and the calibration solution includes a predetermined concentration of glucose.
In accordance with another aspect of the present invention, a method of supplying a fluid to a placement site includes the step of mounting the sensor set onto a skin of a user and contacting a placement site. The sensor set includes a base, a cannula and a sensor as described above. Next, the fluid is introduced through the port of the lumen to the placement site.
In a preferred embodiment, the sensor set further includes an insertion device operatively coupled to the sensor set and the cannula to facilitate insertion of the cannula to contact the placement set.
A more specific preferred embodiment of the foregoing method employs a sensor set that further includes a septum disposed adjacent to the at least one port of the cannula. The fluid is introduced through the septum and the lumen to the placement site.
Another more specific preferred embodiment of the foregoing method employs a sensor set that further includes an externally extending conduit in fluid communication with the at least one port of the cannula. In this embodiment, the fluid is introduced through the externally extending conduit and the lumen to the placement site.
In accordance with a further aspect of the present invention, a method of supplying a fluid to a placement site includes the steps of mounting a sensor set onto a skin of a user and contacting the placement site. The sensor set includes a base, a cannula, an externally extending conduit, and a sensor, as described herein. Next, fluid is introduced through the externally extending conduit and the lumen to the placement site.
In accordance with yet another aspect of the present invention, a method of calibrating a sensor which is placed at a placement site and which is adapted to determine a body characteristic of a user is provided. According to the inventive method, a sensor set is first mounted onto a skin of a user, and the placement site is contacted. The sensor set incl
Hague Clifford W.
Mann Alfred E.
Mastrototaro John J.
MiniMed Inc.
MiniMed Inc.
Nguyen Anhtuan T.
Thissell Jeremy
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