Non-invasive intravascular volume index monitor
View Patent ↗A non-invasive electronic patient monitor tracks one or more physiological parameters of a patient, such as intravascular volume index (IVI), extravascular volume index (EVI), total hemoglobin (SpHb), impedance, and/or weight. The patient monitor determines if one or more of the physiological parameters are within a predetermined range. The patient monitor activates an alarm if one or more of the physiological parameters are outside the predetermined range and indicates a patient can be experiencing edema and/or heart failure, or sepsis.
1. A non-invasive multi-parameter patient monitoring system configured to detect edema for a patient, the non-invasive multi-parameter patient monitoring system comprising:
a sensor having at least one emitter and an associated detector configured to attach to a tissue site, said detector providing a detector signal responsive to an intensity of energy from said emitter after it has passed through said tissue site; and
a patient monitor comprising:
a sensor interface configured to receive said detector signal from said sensor; and
a processor configured to:
determine a plurality of total hemoglobin (SpHb) values over a time period based at least in part on a plurality of detector signals received over the time period;
determine a plurality of intravascular volume index (IVI) levels of a patient over the time period based at least in part on the plurality of determined SpHb value;
determine a patient-specific IVI threshold based at least in part on the determined plurality of IVI levels;
determine a subsequent IVI level based at least in part on a SpHb value determined subsequent to the plurality of SpHb values; and
detect and/or monitor a progress of edema based at least in part on a determination that the subsequent WI level does not satisfy the determined patient-specific IVI threshold.
2. The system of claim 1 , wherein the plurality of IVI levels are determined based on an amount of light detected by the detector.
3. The system of claim 1 , further comprising a host instrument configured to activate an alert based at least in part on a determination that the subsequent IVI level satisfies the determined patient-specific IVI threshold.
4. The system of claim 1 , wherein the patient monitor is further configured to track impedance of the patient and track weight levels of the patient.
5. The system of claim 4 , wherein the patient monitor is further configured to detect and/or monitor the progress of edema by comparing the tracked impedance with a patient-specific impedance threshold and comparing the tracked weight levels with a patient-specific weight level threshold.
6. The system of claim 5 , further comprising a host instrument configured to activate an alert based at least in part on a determination that the subsequent IVI level satisfies the determined patient-specific IVI threshold, the tracked impedance satisfies the patient-specific impedance threshold, and the tracked weight levels satisfy the patient-specific weight level threshold.
7. A method for detecting and/or monitoring progression of edema for a patient, the method comprising:
receiving data at a non-invasive multi-parameter patient monitor, wherein the data is obtained by detecting light from a light emitting element after the light has been attenuated by tissue;
determining a plurality of total hemoglobin (SpHb) values over a time period based at least in part on the received data;
determining a plurality of IVI levels over the time period using the non-invasive multi-parameter patient monitor based at least in part on the plurality of determined SpHb values;
determine a patient-specific IVI threshold based at least in part on the determined plurality of IVI levels;
determine a subsequent IVI level based at least in part on a SpHb value determined subsequent to the plurality of SpHb values;
detecting and/or monitoring a progress of edema based at least in part on a determination that the subsequent IVI level does not satisfy the determined patient-specific IVI threshold.
8. The method of claim 7 , further comprising indicating edema based at least in part on a determination that the subsequent IVI level is equal to or greater than the patient-specific IVI threshold.
9. The method of claim 7 , further comprising:
tracking at least one of weight levels and impedance of the patient; and
detecting and/or monitoring the progress of edema based at least in part on the tracked at least one of weight levels and impedance of the patient.
10. A non-invasive multi-parameter patient monitor configured to detect and/or measure progression of edema, the non-invasive multi-parameter patient monitor comprising:
a sensor interface configured to receive a signal from a sensor, wherein the signal is responsive to an intensity of energy from an emitter after it has passed through a tissue site and the signal is indicative of intravascular volume index (WI) levels at the tissue site;
a processor configured to:
calculate a plurality of total hemoglobin (SpHb) values over a time period based at least in part on a plurality of signals received over the time period;
determine a plurality of IVI levels of a patient over the time period based at least in part on the plurality of SpHb values;
determine a patient-specific IVI threshold based at least in part on the determined plurality of IVI levels;
determine a subsequent IVI level based at least in part on a SpHb value determined subsequent to the plurality of SpHb values; and
activate an alert based at least in part on a determination that the subsequent IVI level satisfies the determined patient-specific IVI threshold.
11. A method for detecting and/or monitoring progression of edema using a non-invasive multi-parameter patient monitor, the method comprising:
emitting light of at least two different wavelengths from a light emitting element;
detecting light from the light emitting element after the light has been attenuated by tissue;
measuring a plurality of intravascular volume index (IVI) levels of a patient over a time period based at least in part on a plurality of total hemoglobin (SpHb) values determined over the time period from the detected light using a non-invasive multi-parameter patient monitor;
determining a patient-specific IVI threshold based at least in part on the measured plurality of IVI levels;
determining a subsequent IVI level based at least in part a SpHb value determined subsequent to the plurality of SpHb values;
detecting and/or monitoring a progress of edema based at least in part on a determination that the subsequent IVI level does not satisfy the determined patient-specific IVI threshold; and
alerting a user of the detection and/or progression of edema based at least in part on a determination that the subsequent IVI level satisfies the determined patient-specific IVI threshold.