Non-invasive method and apparatus to detect and monitor early medical shock, and related conditions
First Claim
1. A diagnostic medical instrument adapted to determine whether a patient is suffering from a pre-shock, shock or shock-related condition, the instrument being used in a capillary filling time (CFT) test procedure in which a skin area of the patient overlying blood-filled capillaries normally imparting to the skin a pink color is depressed by a pressure, which is sufficient to expel blood from the capillaries while maintaining normal flow in the veins, said pressure causing the skin to blanch until the skin exhibits a white color, the said pressure being released when a point of maximum blanching is reached to permit blood to flow back to the capillaries at a rate that depends on the condition of the patient to cause the skin to regain its natural pink color;
- said instrument comprising;
I. means including a color sensor trained on the skin area when exposed to light to generate a signal having a magnitude which is a function of light reflected by the skin area whose intensity depends on the natural color of the skin area, wherein the color sensor means includes means to illuminate the skin area with non-modulated light from a light source, and a light reflected therefrom is intercepted by a photodetector, which yields a signal that depends on an existing skin color;
II. means responsive to said signal before pressure is applied to the skin area to determine its natural pink color to establish a reference base for the test to follow; and
III. means responsive to said signal when pressure is applied to said skin during the test to measure the time elapsing from a starting point in time when the depressed skin is at its maximum blanching value of white, and the pressure applied thereon is then released to cause the capillaries to proceed to full with blood, to a final point in time when the skin recovers its natural pink color as established by the reference base, whereby the CFT measurement is an index to whether the patient is suffering from a shock-related condition, and to the severity of this condition.
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Accused Products
Abstract
A diagnostic medical instrument adapted to determine whether a patient is suffering from a pre-shock, shock, or shock-related condition. The instrument is used in a capillary filling time CFT test procedure in which a skin area in the patient which overlies blood-filled capillaries which normally display a pink color is depressed to expel blood from the capillaries and impart white color to the skin at which point the pressure is released to permit blood to flow back into the capillaries and cause the skin to regain its pink color. The instrument includes a color sensor trained on the skin area and responsive to light reflected therefrom to produce a first signal at the point in time the skin color tuns from pink to white and to later produce a second signal at the point in time at which the skin color has turned from white to pink. The time elapsing between the first and second signals is measured to provide a CFT index indicative of the patient'"'"'s condition.
19 Citations
54 Claims
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1. A diagnostic medical instrument adapted to determine whether a patient is suffering from a pre-shock, shock or shock-related condition, the instrument being used in a capillary filling time (CFT) test procedure in which a skin area of the patient overlying blood-filled capillaries normally imparting to the skin a pink color is depressed by a pressure, which is sufficient to expel blood from the capillaries while maintaining normal flow in the veins, said pressure causing the skin to blanch until the skin exhibits a white color, the said pressure being released when a point of maximum blanching is reached to permit blood to flow back to the capillaries at a rate that depends on the condition of the patient to cause the skin to regain its natural pink color;
- said instrument comprising;
I. means including a color sensor trained on the skin area when exposed to light to generate a signal having a magnitude which is a function of light reflected by the skin area whose intensity depends on the natural color of the skin area, wherein the color sensor means includes means to illuminate the skin area with non-modulated light from a light source, and a light reflected therefrom is intercepted by a photodetector, which yields a signal that depends on an existing skin color; II. means responsive to said signal before pressure is applied to the skin area to determine its natural pink color to establish a reference base for the test to follow; and III. means responsive to said signal when pressure is applied to said skin during the test to measure the time elapsing from a starting point in time when the depressed skin is at its maximum blanching value of white, and the pressure applied thereon is then released to cause the capillaries to proceed to full with blood, to a final point in time when the skin recovers its natural pink color as established by the reference base, whereby the CFT measurement is an index to whether the patient is suffering from a shock-related condition, and to the severity of this condition. - View Dependent Claims (2, 3, 4, 5)
- said instrument comprising;
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6. A method for the diagnosis of a shock-related state in a patient by measuring the filling time of blood vessels subjacent to skin area of the patient, comprising the steps of:
- illuminating the area which is to be gauged for color with a nonmodulated light from a light source, filtering out background noises to obtain a base-line measurement, applying a pressure on said area and rapidly releasing said pressure, and determining the filling time of blood vessels in said area by comparison of a current color of the area after said releasing with the base-line measurement.
- View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. Apparatus for the diagnosis of a shock-related state in a patient and of recovery of a patient therefrom comprising:
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i) means for illuminating a skin area of the patient to be gauged for color with a light from a light source, wherein said light is non-modulated; ii) means for filtering out background noises and light to obtain a base-line measurement; and iii) means for comparing the color of the skin area with the base-line measurement, thereby determining the filling time of blood vessels in said area.
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22. Apparatus for the diagnosis of a shock-related state in a patient and of recovery of a patient therefrom, comprising:
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i) a light source for illuminating an area of the patient'"'"'s skin overlying blood vessels, said area having an original color, wherein said light is substantially non-modulated; ii) a light sensor for intercepting light reflected from said area and producing a first signal having a magnitude which corresponds to the color of said area, said color representing the level of reflection from blood vessels subjacent said area; iii) a filter for filtering said first electrical signal and for rejecting unwanted electrical signals originating in interfering light, and for producing a second signal, whose amplitude is proportional to the amplitude of said filtered first signal; iv) means for storing the amplitude value of said second signal which corresponds to said original color; v) a transducer for applying pressure on said area, and for obtaining an amplitude of the second signal which corresponds to maximum whitening of said area; vi) a processor for processing data collected by said transducer and for measuring the filling time of blood vessels after releasing said pressure; and vii) means for graphically displaying said processed data. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method for the diagnosis of physiological distress in a patient and for recovery of a patient from a state of physiological distress by measuring the filling time of blood vessels underlying an area of the skin of said patient, comprising the steps of:
- acquiring an image of skin area to be gauged for color illuminated with a non-modulated light from a light source to obtain a base-line color measurement, applying a pressure on said area and rapidly releasing said pressure, and determining the filling time of blood vessels in said area by comparison of the color of at least one more additional images of the gauged skin area after said releasing with said base-line color measurement.
- View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. Apparatus for the diagnosis of physiological distress in a patient and of recovery of a patient from physiological distress in accordance with changes in color of the patient'"'"'s skin in response to an applied pressure on said skin, said pressure expelling blood from blood vessels subjacent to said skin, said apparatus comprising:
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i) image acquisition means for acquiring an image of an area of the skin of said patient to be gauged for color, said image acquisition means being trained in the area so that it lies essentially within the focal plane of said image acquisition means; ii) means for illuminating the area of the skin to be gauged for color with light radiation at a level sufficient to enable the image acquisition means to discriminate between colors, wherein the illumination means provides one of modulated light and non-modulated light; iii) means for obtaining a baseline color measurement using the acquired image data corresponding to the color of said area when essentially no pressure is applied thereto; and iv) means for comparing the color of said area with the base-line color measurement, thereby determining the filling time of blood vessels in said area after releasing said pressure. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54)
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Specification