Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
1999-03-11
2001-03-06
Nasser, Robert L. (Department: 3736)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
active
06198953
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field
The invention is concerned primarily with the recovering and sensing of sweat induced by iontophoresis for diagnosing the presence of cystic fibrosis in children or adults, especially the heretofore neglected area of obtaining and sensing sweat of newborn infants, but is also concerned with the sensing of sweat however induced or recovered from an area of a person's skin that is usually selected in advance.
2. State of the Art
Webster U.S. Pat. No. 4,383,529 and Webster et al. U.S. Pat. No. 4,542,751, both assigned to Wescor, Inc., Logan, Utah, disclose and describe in detail what have become standard devices and standard procedures for this diagnostic area of medical practice.
Thus, in Webster et al. U.S. Pat. No. 4,542,751 a sweat-collection device having a shallowly concave, sweat-collecting surface is applied to a patient's skin over an area that has been stimulated by iontophoresis. A length of flexible, plastic tubing has one end connected to an axial bore through which such plastic tubing extends for receiving a sample of sweat to be transferred to sweat-analyzing equipment. A strap secured to opposite ends of the sweat-collection device enables such device to be securely held in place against and covering a selected area of skin of a person to be diagnosed, which skin area has been previously subjected to iontophoresis for inducing sweating of that portion of the person's skin.
For iontophoresis prior to application of the above-referenced sweat-collection device, a pair of iontophoretic electrode devices are employed in accordance with Webster U.S. Pat. No. 4,383,529, thereby inducing sweating at the selected area of the person's skin. Such iontophoretic electrode devices may be and usually are mutually similar for convenience, but one is electrically positive for supplying the sweat-causing ions and the other electrically negative for completing an electrical circuit. At least the positive electrode device comprises a receptacle for holding an agar gel disc carrying an iontophoretic drug (usually pilocarpine). The agar gel disc has an exposed surface for contacting the selected area of skin and an opposite surface in electrical contact with an electrically positive electrode, so that the drug is applied to the thereby covered area of skin for stimulating the sweat glands of such area of skin. The other, an electrically negative electrode device, is conveniently the same, except for being electrically negative rather than positive and may be left in place or may be removed following sweat recovery. In any event, the electrically positive electrode device is replaced by the sweat-collecting device of Webster et al. U.S. Pat. No. 4,542,751 for collecting the induced sweat to be analyzed for diagnostic purposes.
SUMMARY OF THE INVENTION
In working to overcome problems posed by attempts to similarly diagnose cystic fibrosis in newly born infants, whose limbs are usually incapable of accommodating the foregoing devices as designed for children and adults, we have developed a new system for applying the sweat-inducing drug to, and for recovering and testing substantially all of the induced sweat from, the limited sweat-producing skin area concerned, so as to effectively cope with the very small amounts of sweat that can be induced in and recovered from neonates.
In accordance with one aspect of the invention, at least one receiving and holding device is provided for, first, receiving and holding the electrically positive iontophoretic electrode device over a selected area of skin of a patient to be induced to sweat, and, then, following removal of such electrically positive iontophoretic electrode device, for receiving and holding the sweat-sensing device over substantially the same area of skin. The electrically positive electrode device is preferably constructed in accordance with Webster U.S. Pat. No. 4,383,529, but is supplied with structure for holding it in place in the receiving and holding device. A second and preferably similar receiving and holding device is provided for receiving and holding a preferably similar but electrically negative iontophoretic electrode device on the skin of the patient adjacent to the selected sweating area to complete the iontophoretic electrical circuit. It is of particular significance that, in accordance with this aspect of the invention, the sweat-sensing electrode device be placed substantially in registry with or substantially completely covering the selected area of the skin in which sweating is induced so as to recover substantially all of the sweat produced. This is especially important in the diagnosing of neonates, because of the limited amount of sweat produced by them, but also constitutes an improvement on the equipment and procedures of the aforementioned Webster et al. patents owned by Wescor, Inc. of Logan, Utah, and marketed by it under the registered trademark “MACRODUCT”.
As previously indicated, in accordance with one preferred aspect of this invention a sweat-sensing electrode device having at least two sensing electrodes replaces the electrically positive iontophoretic electrode device following use thereof for iontophoretic purpose . Such sweat-sensing electrode device is provided for continuously determining on a real-time basis the characteristics or properties of sweat entering such sweat-sensing device as the sweat travels progressively therethrough in an elongate and relatively narrow stream from the entry thereof to a discharge therefrom. Contrary to the previous “MACRODUCT” system, our new overall system may and preferably does do away with the elongate, coiled tube for receiving and storing recovered sweat for subsequent analysis and provides a substitute sweat-recovery device as preferably an integrated unit for the continuous flow of sweat therethrough so that real-time analysis of the sweat recovered from the selected area of the patient's skin can be carried out. The sensing electrode or electrodes of the sweat-sensing device is or are arranged for electrical connection with a sweat-analysis module.
The sweat-sensing device is unique in having a body member that is preferably an integrated body that contains an elongate, relatively narrow passage or passages for the continuous flow of sweat from electrical communication (preferably direct contact) with one sweat-sensing electrode to another sweat-sensing electrode as serially arranged, and that such sweat-sensing device is held by the previously-indicated receiving and holding device. This is the best mode presently contemplated for carrying out the present invention, but it should be realized that each feature of the general combination constitutes an inventive subcombination in and of itself and may be used with or without the others. Thus, part or even all of the coiled tube of the sweat-collection device of the prior “MACRODUCT” system could be used along with the receiving and holding device for sequentially receiving, first, an electrically positive, sweat-inducing, iontophoretic electrode device and, then, the unique sweat-sensing electrode device. For example, the “MACRODUCT” system presently used for testing the sweat of adults and small children does not normally require the compactness or continuous real-time testing of the presently disclosed overall system, but could make use of the receiving and holding device disclosed herein.
The unique sweat-sensing electrode device of the present overall combination (and also constituting a subcombination thereof) preferably has a substantially rigid body integrally combining a concave sweat-collecting surface with a relatively narrow, elongate flow passage or passages communicating with serially spaced sensing electrodes for contact by the recovered sweat as it flows by. An entry port for receiving and an exit port for discharging the stream of sweat on a substantially continuous basis are provided so that the sensing electrodes are contacted progressively by the stream of flowing sweat on a substantially continuous basis. Electrical con
Barlow Wayne K.
Briscoe Dennis R.
Quirante Carmelo G.
Thomas Scot B.
Webster Henry L.
Mallinckrodt Philip A.
Mallinckrodt Robert R.
Mallinckrodt & Mallinckrodt
Nasser Robert L.
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