Detecting medical conditions with noninvasive body probes
First Claim
1. A method of improving the diagnostic performance of a probe system for detecting a medical condition in a patient, which probe system includes at least one probe to be applied to a measurement site of the patient for sensing volume or volume-related changes in a monitored body part thereat due to pulsatile arterial blood flow in the body part, comprising:
- providing a probe that includes a pressure sensor which senses said volume changes by sensing changes in pressure in a compressible fluid system of volume VF when applied to said monitored body part and of volume VS where not applied to said body part, said body part including a fixed volume VT of non-compressible tissue and a pulsitatively-variable volume VP corresponding to arterial volume changes, such that the pressure in said compressible fluid system changes with the change in pulsatile volume thereof and the gain of said changes varies according to the relative values of the volumes VT and VF;
calibrating said probe system for the respective measurement site of the respective patient according to a predetermined characteristic of said monitored body part of the patient; and
quantifying the arterial pulsatile volume thereat using a data processor.
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Abstract
A method and apparatus for improving the diagnostic performance of a probe system (30) for detecting a medical condition in a patient by sensing volume changes in a monitored body part due to pulsatile arterial blood flow in the body part, characterized in calibrating the probe system (30) for the respective measurement site according to a predetermined characteristic of the monitored body part of the patient and quantifying the arterial pulsatile volume thereat. Such calibration is described with respect to probes including: (1) a pressure sensor (63), which senses pressure changes in a compressible fluid system to which the patient'"'"'s body part (e.g., finger, toe or a distal portion of a limb) is subjected, which pressure changes are convertible to volume changes in the body part due to pulsatile arterial blood volume changes therein; and (2) an optical sensor (140), which senses optical density or transmissivity changes in the body part, which changes are also convertible to volume changes due to pulsatile arterial blood volume changes in the body part.
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Citations
36 Claims
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1. A method of improving the diagnostic performance of a probe system for detecting a medical condition in a patient, which probe system includes at least one probe to be applied to a measurement site of the patient for sensing volume or volume-related changes in a monitored body part thereat due to pulsatile arterial blood flow in the body part, comprising:
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providing a probe that includes a pressure sensor which senses said volume changes by sensing changes in pressure in a compressible fluid system of volume VF when applied to said monitored body part and of volume VS where not applied to said body part, said body part including a fixed volume VT of non-compressible tissue and a pulsitatively-variable volume VP corresponding to arterial volume changes, such that the pressure in said compressible fluid system changes with the change in pulsatile volume thereof and the gain of said changes varies according to the relative values of the volumes VT and VF; calibrating said probe system for the respective measurement site of the respective patient according to a predetermined characteristic of said monitored body part of the patient; and quantifying the arterial pulsatile volume thereat using a data processor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of improving the diagnostic performance of a probe system for detecting a medical condition in a patient, which probe system includes at least one probe to be applied to a measurement site of the patient for sensing volume or volume-related changes in a monitored body part thereat due to pulsatile arterial blood flow in the body part comprising,
providing a probe that includes an optical sensor having a light source and a light receiver; -
wherein said probe is calibrated for the respective patient by the use of a model which modifies said light source to produce in said light receiver a waveform simulating that produced by the pulsatile arterial blood flow in the monitored body part of the respective patient, calibrating said probe system for the respective measurement site of the respective patient according to a predetermined characteristic of said monitored body part of the patient, and quantifying the arterial pulsatile volume thereat using a data processor. - View Dependent Claims (15, 16)
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17. Apparatus for detecting a medical condition of a patient, comprising:
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a probe system including a probe to be applied to a measurement site of the patient for sensing volume or volume-related changes in a monitored body part thereat due to pulsatile arterial blood flow in the body part; and calibrating means for calibrating said probe system for the respective measurement site, according to a predetermined physical characteristic of the body part of the respective patient, and for quantifying the arterial pulse volume thereat; wherein said probe includes a pressure sensor which senses said volume changes by sensing changes in pressure in a compressible fluid system of volume VF when applied to said monitored body part and of volume VS where not applied to said body part, said body part including a fixed volume VT of non-compressible tissue and a pulsitatively-variable volume VP corresponding to arterial volume changes, such that the pressure in said compressible fluid system changes with the change in pulsatile volume thereof and the gain of said changes varies according to the relative values of the volumes VT and VF. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. Apparatus for detecting a medical condition of a patient, comprising:
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a probe system including a probe to be applied to a measurement site of the patient for sensing volume or volume-related changes in a monitored body part thereat due to pulsatile arterial blood flow in the body part; and calibrating means for calibrating said probe system for the respective measurement site, according to a predetermined physical characteristic of the body part of the respective patient, and for quantifying the arterial pulse volume thereat; wherein said probe system includes an optical sensor having a light source and a light receiver; and wherein said apparatus further includes for calibrating the probe system for the measurement site of the respective patient, a model which modifies said light source to produce in said light receiver a waveform simulating that produced by the pulsatile arterial blood flow in the body part of the respective patient. - View Dependent Claims (33, 34, 35, 36)
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Specification