Liquid crystal infiltration sensing system
First Claim
1. A method of detecting infiltration of infusion fluid into a patient'"'"'s body tissues surrounding the point of infusion into a vessel, said method comprising the steps of:
- puncturing the patient'"'"'s skin with an infusion apparatus to infuse fluid into said vessel;
affixing and conforming to the skin of the patient, at a location immediately downstream of the puncture by the infusion device, a patch of material which changes in color in response to changes in skin temperature, said patch having a first color over a range of temperatures which includes 30°
cent rigrade through 33°
centigrade and having a second color at temperatures below that range; and
observing said affixed patch for changes from said first color to said second color.
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Accused Products
Abstract
A patch of temperature-sensitive liquid crystal material adheres to a patient'"'"'s skin to serve as an indicator of infiltration during intravenous (or intraarterial, intra-lymphatic vessel, etc.) insertion procedures. The material is selected so as to have a constant color over a temperature range which spans the normal skin temperature range. The patch is placed immediately downstream of the insertion point and preferably has a straight forward edge to permit rapid color change over a broad section of the patch in response to infiltration. The patch may include a downstream extension, remote from the likely infiltration region, which experiences infiltration-responsive color change considerably later than the forward edge, thereby providing a color contrast to facilitate visual detection. Alternatively, a portion of the patch is permanently colored to have the same color as the patch at normal skin temperatures; the permanently colored portion therefore provides color contrast when the patch color changes due to infiltration.
45 Citations
11 Claims
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1. A method of detecting infiltration of infusion fluid into a patient'"'"'s body tissues surrounding the point of infusion into a vessel, said method comprising the steps of:
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puncturing the patient'"'"'s skin with an infusion apparatus to infuse fluid into said vessel; affixing and conforming to the skin of the patient, at a location immediately downstream of the puncture by the infusion device, a patch of material which changes in color in response to changes in skin temperature, said patch having a first color over a range of temperatures which includes 30°
cent rigrade through 33°
centigrade and having a second color at temperatures below that range; andobserving said affixed patch for changes from said first color to said second color. - View Dependent Claims (2, 3, 4, 5)
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6. A method of detecting variation in temperature of a liquid from within a pre-determined continuous range of temperatures, said method comprising the steps of:
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providing a patch of thin temperature-sensitive film which has a variable color versus temperature characteristic and which remains at one color when at temperatures within said pre-determined range of temperatures; providing a prescribed area on said patch which is permanently colored at said one color; applying said patch to a surface of a body in which said liquid is disposed below said surface; and observing the applied patch to determine if the variable color portion differs from said one color of said prescribed area. - View Dependent Claims (7, 8, 9, 10)
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11. A method of monitoring temperature change of a substance in a body at a surface of the body which is not in direct contact with the substance by adhering a patch of liquid crystal material to said surface, said liquid crystal material having a variable color versus temperature characteristic wherein the material remains at one color over a pre-determined range of temperatures and varies from that color when the temperature of the patch varies outside said pre-determined range, said method comprising the steps of:
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providing a prescribed area on said patch which is permanently colored at said one color; and observing the applied patch to determine if the variable color portion differs from the color of said prescribed area.
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Specification