US4378808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal infiltration sensing system
Assignee: Whitman Medical Corp
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Filing: 1980-04-07
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Granted: 1983-04-05
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Expires: 2000-04-07
Abstract
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.
Inventors
- 👤 Joseph Lichtenstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:03
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/01; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16831; A61M5/16836; Y; Y10; Y10S; Y10S252/00; Y10S252/962
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
120 words
A device for detecting infiltration of infusion fluid in human body tissue surrounding a point of infusion into a body vessel of a patient, said device comprising a flexible patch of liquid crystal material, said patch having an underside which conforms to the patient's skin at a location proximate said point of infusion, said liquid crystal material having a variable color versus temperature characteristic wherein the material remains at one color when at normal human skin temperature, said patch having a straight edge positioned closest to said point of infusion and having corners which are all rounded, said liquid crystal material further including an integral prescribed area located within the confines of the patch permanently colored at said one color.
Claim 2
Independent Claim
120 words
A device for detecting infiltration of infusion fluid in human body tissue surrounding a point of infusion into a body vessel of a patient, said device comprising a flexible patch of liquid crystal material, said patch having an underside which conforms to the patient's skin at a location proximate said point of infusion, said liquid crystal material having a variable color versus temperature characteristic wherein the material remains at one color when at normal human skin temperature, said patch having a straight edge positioned closest to said point of infusion and having corners which are all rounded, said liquid crystal material further including an integral prescribed area located within the confines of the patch permanently colored at said one color.
Claim 3
Dependent Claim
16 words
The device according to claim 1 wherein said patch is between two and twenty mils thick.
Claim 4
Dependent Claim
25 words
The device according to claim 1 wherein said patch includes at least on co-planar projection extending form an edge generally opposite to said straight edge.
Claim 5
Dependent Claim
23 words
The device according to claim 1 wherein said prescribed area is a dot-like area disposed inwardly from all peripheral edges of said patch.
Claim 6
Dependent Claim
37 words
The device according to claim 1 wherein said one color is blue and wherein said patch changes colors to green, yellow, red brown and black over a range of temperatures extending from 28° centigrade to 24° centigrade.
Claim 7
Dependent Claim
16 words
The device according to claim 1 wherein said prescribed area at least partially borders said patch.
Claim 8
Independent Claim
73 words
A device for detecting sub-cutaneous temperature changes comprising a flexible patch of liquid crystal material having an underside which conforms to a patient's skin, said liquid crystal material having a variable color versus temperature characteristic wherein the material remains at one color over a predetermined range of temperatures, the area of said liquid crystal material comprising a major portion of said patch, said patch including a prescribed area permanently having said one color.
Claim 9
Independent Claim
73 words
A device for detecting sub-cutaneous temperature changes comprising a flexible patch of liquid crystal material having an underside which conforms to a patient's skin, said liquid crystal material having a variable color versus temperature characteristic wherein the material remains at one color over a predetermined range of temperatures, the area of said liquid crystal material comprising a major portion of said patch, said patch including a prescribed area permanently having said one color.
Claim 10
Dependent Claim
16 words
The device according to claim 7 wherein said prescribed area includes the border of said patch.
Claim 11
Dependent Claim
14 words
The device according to claim 7 wherein said prescribed area is a dot-like region.
Claim 12
Dependent Claim
112 words
A temperature measuring device for measuring variation of localized sub-cutaneous temperature in a patient from a predetermined range of normal temperatures, said device comprising: a flexible patch including liquid crystal material adapted to be placed on a patient's skin, said liquid crystal material having a visually-perceptible color versus temperature characteristic wherein the material remains at one prescribed color over said predetermined range of normal temperatures and varies from that prescribed color outside said predetermined range of normal temperatures, the area of said liquid crystal material comprising a major portion of said patch, said patch including a smaller integral prescribed area which is permanently at said one prescribed color irrespective of temperature changes.
Claim 13
Dependent Claim
112 words
A temperature measuring device for measuring variation of localized sub-cutaneous temperature in a patient from a predetermined range of normal temperatures, said device comprising: a flexible patch including liquid crystal material adapted to be placed on a patient's skin, said liquid crystal material having a visually-perceptible color versus temperature characteristic wherein the material remains at one prescribed color over said predetermined range of normal temperatures and varies from that prescribed color outside said predetermined range of normal temperatures, the area of said liquid crystal material comprising a major portion of said patch, said patch including a smaller integral prescribed area which is permanently at said one prescribed color irrespective of temperature changes.
Claim 14
Dependent Claim
16 words
The device according to claim 10 wherein said prescribed area at least partially borders said patch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-04 | 1986-10-04 | 1987-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-04 | 1990-10-04 | 1991-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-04 | 1994-10-04 | 1995-04-05 | $7700.00 | Window Closed / Lapsed |