Apparatus and method for locating a medical tube in the body of a patient
First Claim
1. An apparatus for detecting the location of a magnet associated with a medical tube within the body of a patient, comprising:
- means for sensing a first static magnetic field strength at a first distance from the magnet and providing a first sensor signal which is a function of the first static magnetic field strength;
means for sensing a second static magnetic field strength at a second distance from the magnet and providing a second sensor signal which is a function of the second static magnetic field strength, wherein the second distance is greater than the first distance;
means for receiving the first sensor signal and providing a first detection signal which is a function of the first sensor signal, wherein the means for receiving the first sensor signal and providing the first detection signal comprises a first amplifier for receiving the first sensor signal and providing a first amplified signal which is proportional to the first sensor signal, and a first integrator for receiving the first amplified signal and providing the first detection signal;
means for receiving the second sensor signal and providing a second detection signal which is a function of the second sensor signal, wherein the means for receiving the second sensor signal and providing the second detection signal comprises a second amplifier for receiving the second sensor signal and providing a second amplified signal which is proportional to the second sensor signal, and a second integrator for receiving the second amplified signal and providing the second detection signal;
means for receiving the first and second detection signals and providing a differential signal which is a function of the difference between the first detection signal and the second detection signal; and
means for receiving and indicating a value for the differential signal.
1 Assignment
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Accused Products
Abstract
There is disclosed an apparatus and method for locating a medical tube within the body of a patient. The medical tube is located by a detection apparatus which senses the static magnetic field strength gradient generated by a magnet associated with the medical tube and indicates the value of the gradient to the user. The detection apparatus is moved about the body of the patient until the greatest gradient magnitude is indicated. The detection apparatus distinguishes the field strength of the magnet associated with the medical tube from the earth'"'"'s field strength by sensing the magnet'"'"'s field strength at two different distances from the magnet.
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Citations
25 Claims
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1. An apparatus for detecting the location of a magnet associated with a medical tube within the body of a patient, comprising:
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means for sensing a first static magnetic field strength at a first distance from the magnet and providing a first sensor signal which is a function of the first static magnetic field strength; means for sensing a second static magnetic field strength at a second distance from the magnet and providing a second sensor signal which is a function of the second static magnetic field strength, wherein the second distance is greater than the first distance; means for receiving the first sensor signal and providing a first detection signal which is a function of the first sensor signal, wherein the means for receiving the first sensor signal and providing the first detection signal comprises a first amplifier for receiving the first sensor signal and providing a first amplified signal which is proportional to the first sensor signal, and a first integrator for receiving the first amplified signal and providing the first detection signal; means for receiving the second sensor signal and providing a second detection signal which is a function of the second sensor signal, wherein the means for receiving the second sensor signal and providing the second detection signal comprises a second amplifier for receiving the second sensor signal and providing a second amplified signal which is proportional to the second sensor signal, and a second integrator for receiving the second amplified signal and providing the second detection signal; means for receiving the first and second detection signals and providing a differential signal which is a function of the difference between the first detection signal and the second detection signal; and means for receiving and indicating a value for the differential signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of detecting the location of a magnet associated with a medical tube within the body of a patient, comprising:
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sensing a first static magnetic field strength at a first distance from the magnet; sensing a second static magnetic field strength at a second distance from the magnet which is greater than the first distance; providing a first sensor signal which is a function of the first static magnetic field strength, wherein the first sensor signal is a vector; providing a second sensor signal which is a function of the second static magnetic field strengths wherein the second sensor signal is a vector; receiving the first and second sensor signals and providing a differential signal which is a function of the difference between the first static magnetic field strength and the second static magnetic field strengths Wherein the differential signal is a vector; receiving and indicating a value for the differential signal; and determining the location of the medical tube by varying the first and second distances until the greatest value for the differential signal is indicated. - View Dependent Claims (12, 13, 14)
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15. A method of verifying the location of a magnet associated with a medical tube within the body of a patient, comprising:
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sensing a first static magnetic field strength at a first distance from the magnet; sensing a second static magnetic field strength at a second distance from the magnet which is greater than the first distance; providing a first sensor signal which is a function of the first static magnetic field strength; providing a second sensor signal which is a function of the second static magnetic field strength; receiving the first and second sensor signals and providing a differential signal which is a function of the difference between the first static magnetic field strength and the second static magnetic field strength; receiving and indicating the polarity of the differential signal; manipulating the magnet until the indicated polarity of the differential signal changes; and monitoring variations in the first and second static magnetic field strengths to further verify the location of the medical tube. - View Dependent Claims (16)
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17. An apparatus for detecting the location of a magnet associated with a medical tube within the body of a patient, comprising:
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a static magnetic field strength sensor driver for providing a driver signal wherein the driver signal is a vector; a first static magnetic field strength sensor in communication with the static magnetic field strength sensor driver for receiving the driver signal and thereby providing a first sensor signal which is a function of a first static magnetic field strength at a first distance from the magnet, wherein the first sensor signal is a vector; a second static magnetic field strength sensor in communication with the static magnetic field strength sensor driver for receiving the driver signal and thereby providing a second sensor signal which is a function of a second static magnetic field strength at a second distance from the magnet, wherein the second distance is greater than the first distance, wherein the second sensor signal is a vector; a first amplifier in communication with the first static magnetic field strength sensor for receiving the first sensor signal and providing a first amplified signal which is proportional to the first sensor signal, wherein the first amplified signal is a vector; a first integrator in communication with the first amplifier for receiving the first amplified signal and providing a first detection signal which is a function of the first sensor signal, wherein the first detection signal is a vector; a second amplifier in communication with the second static magnetic field strength sensor for receiving the second sensor signal and providing a second amplified signal which is proportional to the second sensor signal, wherein the second amplified signal is a vector; a second integrator in communication with the second amplifier for receiving the second amplified signal and providing a second detection signal which is a function of the second sensor signal, wherein the second detection signal is a vector; a differential amplifier in communication with the first and second integrators for receiving the first and second detection signals and providing a differential signal which is a function of the difference between the first detection signal and the second detection signal, wherein the differential signal is a vector; a magnitude circuit in communication with the differential amplifier for receiving the differential signal and providing a magnitude signal which is proportional to the magnitude of the differential signal; a visual display signal driver in communication with the magnitude circuit for receiving the magnitude signal and providing a visual display signal; and a visual display in communication with the visual display signal driver for receiving and visually indicating the visual display signal. - View Dependent Claims (18, 19, 20, 21, 22)
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23. An apparatus for detecting the location of a magnet associated with a medical tube within the body of a patient, comprising:
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a first static magnetic field strength sensor for providing a first sensor signal which is a function of a first static magnetic field strength at a first distance from the magnet, wherein the first sensor signal is a vector; a second static magnetic field strength sensor for providing a second sensor signal which is a function of a second static magnetic field strength at a second distance form the magnet, wherein the second distance is greater than the first distance, wherein the second sensor signal is a vector; a first detector in communication with the first sensor for receiving the first sensor signal and providing a first detection signal which is a function of the first sensor signal, wherein the first detection signal is a vector; a second detector in communication with the second sensor for receiving the second sensor signal and providing a second detection signal which is a function of the second sensor signal, wherein the second detection signal is a vector; a microprocessor in communication with the first and second detectors for receiving the first and second detection signals and providing a differential signal which is a function of the difference between the first detection signal and the second detection signal, wherein the differential signal is a vector; a magnitude circuit in communication with the microprocessor for receiving the differential signal and providing a magnitude signal which is proportional to the magnitude of the differential signal; and an indicator in communication with the magnitude circuit for receiving the magnitude signal and indicating its value. - View Dependent Claims (24, 25)
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Specification