Modulated physiological sensor
A modulated physiological sensor is a noninvasive device responsive to a physiological reaction of a living being to an internal or external perturbation that propagates to a skin surface area. The modulated physiological sensor has a detector configured to generate a signal responsive to the physiological reaction. A modulator varies the coupling of the detector to the skin so as to at least intermittently maximize the detector signal. A monitor controls the modulator and receives an effectively amplified detector signal, which is processed to calculate a physiological parameter indicative of the physiological reaction.
1. A physiological monitoring system configured to monitor a physiological parameter of a patient, said physiological monitoring system comprising:
an optical sensor including one or more components, said one or more components comprising at least one emitter configured to transmit optical radiation into a tissue site of the patient and at least one detector configured to detect a plethysmograph waveform responsive to attenuation of the transmitted optical radiation by the tissue site,
a first motor and a second motor separated from the first motor by an isolator, wherein the first motor and the second motor is configured to vary a respective coupling between at least some of the one or more components of the optical sensor and a skin over the tissue site of the patient; and
one or more hardware processors configured to:
control the motor to vary the coupling;
detect a plurality of plethysmograph waveform corresponding to varying coupling of the one or more components of the optical sensor and the skin; and
monitor a physiological parameter responsive to the detected plurality of plethysmograph waveforms.
2. The physiological monitoring system of claim 1 , wherein the coupling is varied to maximize a signal from the detector.
3. The physiological monitoring system of claim 1 , wherein the coupling is continuously varied while detecting the physiological parameter.
4. The physiological monitoring system of claim 1 , further comprising an accelerometer configured to detect a physiological signal.
5. The physiological monitoring system of claim 4 , wherein the accelerometer is configured to be placed proximate to a radial artery.
6. The physiological monitoring system of claim 4 , wherein the physiological parameter is blood pressure measurement.
7. The physiological monitoring system of claim 4 , wherein the motor is further configured to vary a second coupling between the accelerometer and the skin.
8. The physiological monitoring system of claim 1 , wherein the second motor is configured to vary the second coupling.
9. A physiological monitoring method for monitoring a physiological parameter of a patient, said physiological monitoring method comprising:
transmitting, by an optical sensor, optical radiation into a tissue site of the patient, said optical sensor including one or more components, said one or more components comprising at least one emitter and at least one detector;
detecting, by the optical sensor, a plethysmograph waveform responsive to attenuation of the transmitted optical radiation by the tissue site,
controlling a first motor to vary a first coupling between at least some of the one or more components of the optical sensor and a skin over the tissue site of the patient;
controlling a second motor separated from the first motor by an isolator to vary a second coupling between at least other of the some of the one or more components of the optical sensor and the skin;
detecting a plurality of plethysmograph waveform corresponding to varying coupling of the one or more components of the optical sensor and the skin; and
monitoring a physiological parameter responsive to the detected plurality of plethysmograph waveforms.
10. The physiological monitoring method of claim 9 , wherein the coupling is varied to maximize a signal from the at least one detector.
11. The physiological monitoring method of claim 9 , further comprising continuously varying the coupling while detecting the physiological parameter.
12. The physiological monitoring method of claim 9 , further comprising detect, with an accelerometer, a physiological signal.
13. The physiological monitoring method of claim 12 , wherein the accelerometer is configured to be placed proximate to a radial artery.
14. The physiological monitoring method of claim 12 , wherein the physiological parameter is blood pressure measurement.
15. The physiological monitoring method of claim 12 , further comprising varying, with the motor, an accelerometer coupling between the accelerometer and the skin.