Passive physiological monitoring (p2m) system

Abstract

Passive physiological monitoring apparatus and method has a sensor for sensing physiological phenomenon. The sensor is a piezoelectric film of polyvinylidene fluoride. A pad may incorporate the PVDF film. The film converts mechanical energy into voltage signals. A microcomputer is used for recording, analyzing and displaying data from the sensor for on-line assessment and for providing realtime response. The sensor may be an array of sensors provided in a MEDEVAC litter or other patient support for measuring acoustic and hydraulic signals from the body of a patient for field monitoring, hospital monitoring, transport monitoring, home, remote monitoring.

1 - 46 . (canceled) 
     
     
         47 . Apparatus for passively monitoring the physiology of a patient, comprising:
 at least two sensors, each sensor comprising a piezoelectric polymer film, at least one of said sensors being disposed for passively coupling with the patient through a solid or semi-solid interface to detect movements associated with both physiological signals from the patient and vibrations from an environment around the patient, and at least one of said sensors not being coupled with the patient and being disposed to detect movements associated with vibrations in the environment around the patient;   a bandpass filter coupled with each of the sensors for filtering out acoustic signals and isolating sub-acoustic signals within a frequency range of 0.01-4.0 Hz associated with mechanical vibration and movement;   a processor for isolating the physiological signals from the environmental signals by subtracting the signals of the sensor not coupled with the patient from the signals of the sensor coupled with the patient to provide physiological data; and   a display communicating with the processor for displaying the physiological data.   
     
     
         48 . The apparatus of  claim 47 , wherein the piezoelectric polymer film is a polyvinylidene fluoride (PVDF) film. 
     
     
         49 . The apparatus of  claim 47 , wherein the physiological data is selected from the group consisting of heart rate, respiration rate, blood pressure, cardiac output, cardiac function, internal bleeding, patient movement, apnea, pulse strength, blood flow volume, temperature and combinations thereof. 
     
     
         50 . The apparatus of  claim 47 , wherein the processor further performs spectral analysis for discerning the physiological signals from the environmental signals. 
     
     
         51 . The apparatus of  claim 47 , wherein the piezoelectric polymer films are disposed on a patient support, and wherein the patient support is a hospital bed or home bed. 
     
     
         52 . The apparatus of  claim 47 , wherein the piezoelectric films are disposed on a patient support, and wherein the patient support is litter or stretcher. 
     
     
         53 . The apparatus of  claim 47 , wherein the processor calculates a spectrum from the signals and extracts information associated with heart rate and respiration rate of the patient by identifying peaks in the spectrum corresponding to the heart rate and respiration rate of the patient. 
     
     
         54 . The apparatus of  claim 47 , wherein the processor calculates respiration and heart rate by the energy spectrum from time series data provided by the sensors. 
     
     
         55 . The apparatus of  claim 47 , wherein the at least one of said sensors being disposed for passively coupling with the patient comprises at least two sensors disposed to measure pulse wave characteristics at different locations on the patient's body; and
 wherein the processor extracts blood pressure information by calculating the pulse wave velocity or pulse wave travel time based on the temporal separation between the signals received by the sensors.   
     
     
         56 . The apparatus of  claim 47 , wherein the processor transforms the signals into frequency signals including heart rate and respiration harmonics, and differentiates the heart rate and respiration harmonics by comparing signals taken from different locations on the patient's body. 
     
     
         57 . The apparatus of  claim 47 , wherein the at least one of said sensors being disposed for passively coupling with the patient comprises at least two sensors, at least one of said two sensors being disposed to sense data from the patient's foot and another of said two sensors being disposed to sense data from the patient's chest area; and
 wherein the processor isolates energy contributions from the patient's heart by comparing the sensed data from the patient's foot with the sensed data from the patient's chest area.   
     
     
         58 . The apparatus of  claim 47 , wherein
 the sensors are disposed at different locations on a patient support for sensing physiological data from the patient;   the processor processes the signals to extract position dependent physiological from the signals, and   wherein said position dependent physiological signals are used to determine patient position on the support.   
     
     
         59 . The apparatus of  claim 47 , wherein the at least two sensors are disposed on a substrate selected from a group consisting of an item of clothing, a stretcher, a bed, a litter, a cervical collar, body armor, body protection gear, a uniform, an extraction device, exercise equipment, furniture, a cushion, a seat and a seatback. 
     
     
         60 . The apparatus of  claim 47 , wherein a plurality of said sensors are disposed in an array for passively coupling with the patient through a solid or semi-solid interface to detect movements associated with both physiological signals from the patient and vibrations from an environment around the patient, and wherein
 the processor removes noise from the physiological signals by correlating the signals from the plurality of sensors coupled with the patient.   
     
     
         61 . A method for passively monitoring the physiology of a patient in a high noise and vibration environment, comprising:
 coupling a first piezoelectric polymer film sensor with the patient at a location on the patient's body through a solid or semi-solid interface to detect movements associated with both physiological signals from the patient and vibrations from an environment around the patient;   disposing a second piezoelectric polymer film sensor not coupled with the patient for detecting movements associated with vibrations in the environment around the patient;   sensing movement associated with both physiological signals and environmental signals with the first sensor;   sensing movement associated with environmental signals with the second sensor;   bandpass filtering the sensor signals to filter out acoustic signals and isolate the sub-acoustic signals within a frequency range of 0.01-4.0 Hz associated with mechanical vibration and movement;   isolating the physiological signals from the environmental signals by using a processor to subtract the second sensor signal from the first sensor signals; and   displaying the physiological data.   
     
     
         62 . The method of  claim 61 , further comprising coupling a plurality of said first sensors with the patient at different locations on the patient's body to detect movements associated with both physiological signals from the patient and vibrations from an environment around the patient; and
 removing noise from the physiological signals by correlating the signals from the plurality of first sensors.