Patient monitor for monitoring microcirculation
AssigneeMasimo Corporation
InventorMassi Joe E. Kiani
Life of this patent
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Abstract
A patient monitor capable of measuring microcirculation at a tissue site includes a light source, a beam splitter, a photodetector and a patient monitor. Light emitted from the light source is split into a reference arm and a sample arm. The light in the sample arm is directed at a tissue site, such as an eyelid. The reflected light from the tissue site is interfered with the light from the reference arm. The photodetector measures the interference of the light from both the sample arm and the reference arm. The patient monitor uses the measurements from the photodetector to calculate the oxygen saturation at the tissue site and monitor the microcirculation at the tissue site.
Claims20
A method for monitoring microcirculation of a patient at an eyelid, the method comprising:
- receiving a plurality of signals corresponding to light detected by a sensor after having been reflected and/or refracted at a tissue site of an eyelid, wherein the light comprises at least a red beam having a red wavelength and an infrared (IR) beam having an infrared wavelength;
- calculating oxygen saturation based at least in part on a ratio of a first signal of the plurality of signals that corresponds to the red beam with respect to a second signal of the plurality of signals that corresponds to the IR beam;
- calculating a perfusion index based at least in part on a signal strength of at least one of the plurality of signals;
- determining a ratio between the oxygen saturation and the perfusion index;
- comparing the determined ratio with stored microcirculation data corresponding to one or more microcirculation states;
- and
- determining a microcirculation state of at least a portion of blood vessels in the eyelid based at least in part on the comparison of the determined ratio with the stored microcirculation data.
A microcirculation monitoring device configured to monitor the microcirculation of a patient at an eyelid, the monitoring device comprising:
- a light source configured to emit light comprising a plurality of light beams, wherein the plurality of light beams comprises at least a red beam having a red wavelength and an infrared (IR) beam having a IR wavelength;
- a detector configured to detect the light after having been reflected and/or refracted at a tissue site of an eyelid;
- and
- one or more processors in communication with the detector, the one or more processors configured to:
- receive a plurality of signals corresponding to the light detected by the detector, the plurality of signals comprising at least a first signal that corresponds to the red beam and a second signal that corresponds to the IR beam,
- calculate an oxygen saturation based at least in part on a ratio of the first signal with respect to the second signal,
- calculate a perfusion index based at least in part on a signal strength of at least one of the plurality of signals,
- determine a ratio between the oxygen saturation and the perfusion index,
- compare the determined ratio with stored microcirculation data corresponding to one or more microcirculation states, and
- determine a microcirculation state of a least a portion of blood vessels in the eyelid based at least in part on the comparison of the determined ratio with the stored microcirculation.
Dependencies are inferred from the claim text.