Smart physiologic parameter sensor and method

Abstract

A sensor assembly used for the measurement of one or more physiologic parameters of a living subject which is capable of storing both data obtained dynamically during use as well as that programmed into the device. In one embodiment, the sensor assembly comprises a disposable combined pressure and ultrasonic transducer incorporating an electrically erasable programmable read-only memory (EEPROM), the assembly being used for the non-invasive measurement of arterial blood pressure. The sensor EEPROM has a variety of information relating to the manufacture, run time, calibration, and operation of the sensor, as well as application specific data such as patient or health care facility identification. Portions of the data are encrypted to prevent tampering. In a second embodiment, one or more additional storage devices (EEPROMs) are included within the host system to permit the storage of data relating to the system and a variety of different sensors used therewith. In a third embodiment, one or more of the individual transducer elements within the assembly are made separable and disposable, thereby allowing for the replacement of certain selected components which may degrade or become contaminated. Methods for calibrating and operating the disposable sensor assembly in conjunction with its host system are also disclosed.

1 - 36 . cancel  
     
     
         37 . A method of operating a device used for measuring at least one parameter associated with a living subject, said device comprising a host system and a detachable sensor assembly with associated storage device having a first plurality of data stored therein, the method comprising: 
 placing said sensor assembly in data communication with said host system, said host system having a second plurality of data associated therewith;    reading at least a portion of said first plurality of data from said storage device;    evaluating said at least portion of said first plurality of data and at least a portion of said second plurality of data; and    determining whether said sensor assembly is enabled for measuring said at least one parameter based at least in part on said act of evaluating.    
     
     
         38 . The method of  claim 37 , further comprising reading said second plurality of data from a storage device.  
     
     
         39 . The method of  claim 38 , wherein the act of storing a first plurality of data comprises storing said data within an electrically erasable programmable read-only memory (EEPROM).  
     
     
         40 . The method of  claim 37 , wherein said at least portion of said first plurality of data comprises data relating to the date of manufacture of said sensor assembly, and said at least portion of said second data comprises another date which is later than that of said date of manufacture.  
     
     
         41 . The method of  claim 37 , wherein said at least portion of said first plurality of data comprises data relating to the duration of use of said sensor assembly, and said at least portion of said second data comprises a parameter relating to a maximum allowed duration.  
     
     
         42 . The method of  claim 37 , wherein said at least portion of said first plurality of data comprises data relating to the user of said sensor assembly, and said at least portion of said second data comprises a parameter relating to said user.  
     
     
         43 . The method of  claim 37 , wherein said act of evaluating comprises determining if said sensor assembly is compatible with said host system.  
     
     
         44 . The method of  claim 43 , wherein said act of determining if said sensor assembly is compatible with said host system comprises comparing a first multi-bit hexadecimal value in said at least portion of said first data with a corresponding value of said second data.  
     
     
         45 . The method of  claim 37 , wherein said device comprises a device adapted to measure a hemodynamic parameter, and said act of placing comprises physically mating said detachable sensor assembly to a substantially movable portion of said device.  
     
     
         46 . The method of  claim 37 , further comprising calibrating said sensor assembly based at least in part on said first data.  
     
     
         47 . The method of  claim 45 , wherein said enabling for measurement comprises a condition precedent to said act of calibrating said sensor.  
     
     
         48 . The method of  claim 37 , wherein said at least portion of said first data comprises cryptographic data which is uniquely related to complementary cryptographic data of said at least portion of said second data.  
     
     
         49 . A method of operating a device used for measuring at least one parameter associated with a living subject, said device comprising a host system and a detachable sensor assembly with associated storage device having a first plurality of data stored therein, the method comprising: 
 placing said sensor assembly in data communication with said host system;    reading at least a portion of said first plurality of data from said storage device;    creating a test condition within said sensor assembly;    determining at least one value relating to the operation of said sensor assembly relating to said test condition; and    determining whether said sensor assembly is enabled for measuring said at least one parameter based at least in part on said act of measuring.    
     
     
         50 . The method of  claim 49 , wherein said sensor assembly comprises a bridge circuit, and said portion of said first data comprises data relating to the electrical output of said sensor assembly during a shunted condition of said bridge circuit, and said act of determining at least one value comprises: 
 creating substantially the same shunted condition within said sensor assembly; and    obtaining second data relating to the electrical output of said sensor assembly.    
     
     
         51 . A method of recording data, comprising: 
 collecting first data relating to at least one parameter associated with a living subject;    analyzing said first data to generate a first estimate of said at least one parameter;    collecting second data relating to said at least one parameter;    analyzing said second data to generate a second estimate of said at least one parameter;    comparing said first estimate and said second estimate using at least one acceptance criterion; and    storing at least either said first data or said second data in a storage device if said at least one criterion is met.    
     
     
         52 . The method of  claim 51 , wherein the acts of collecting said first and second data each comprise collecting pressure data derived from a tonometric pressure sensor, and said first and second estimates comprise estimates of a blood pressure.  
     
     
         53 . The method of  claim 51 , wherein the acts of analyzing said first and second data comprise determining a time-frequency representation for each.  
     
     
         54 . The method of  claim 51 , wherein the acts of analyzing said first and second data comprise: 
 measuring a first hemodynamic parameter from a blood vessel of said subject;    measuring a second parameter from said blood vessel;    deriving a calibration function based at least in part on said second parameter; and    calibrating the first hemodynamic parameter using said calibration function.    
     
     
         55 . The method of  claim 54 , wherein the act of measuring a first hemodynamic parameter comprises measuring blood velocity.  
     
     
         56 . The method of  claim 51 , further comprising: 
 obtaining third and fourth data relating to the identity of an individual during at least a portion of said acts of collecting said first and second data, respectively; and    comparing said third and fourth data to verify that said identity relating to each is the same.    
     
     
         57 . A method of ensuring the adequacy of a sensor assembly used in measuring at least parameter associated with a living subject, comprising: 
 encoding first data within said sensor assembly, said first data being representative of a first time;    placing said sensor assembly in data communication with a host system;    measuring a second time using said host system;    comparing said first and second times using an acceptance criterion; and    disabling said sensor assembly from further use if said criterion is not satisfied.    
     
     
         58 . The method of  claim 57 , wherein the act of comparing comprises calculating the difference between said first and second times, and comparing said difference to said acceptance criterion.  
     
     
         59 . A method of ensuring the condition of a degradable component within a medical device, comprising: 
 providing a degradable component, said degradable component being adapted to measure at least one physical parameter associated with a living subject;    measuring said at least one parameter of a living subject using said degradable component to obtain first data;    storing said first data relating to said at least one parameter within a storage device;    measuring said at least one parameter a second time using said degradable component to obtain second data;    comparing said first data to the second data using at least one predetermined criterion; and    disabling said medical device if said at least one criterion is not satisfied.    
     
     
         60 . The method of  claim 59 , wherein the act of measuring comprises measuring pressure.  
     
     
         61 . The method of  claim 60 , wherein said at least one predetermined criterion comprises a difference in pressure.  
     
     
         62 . The method of  claim 59 , further comprising deriving first and second estimates of arterial blood pressure based at least in part on said acts of measuring said at least one parameter at said first and second times, respectively.  
     
     
         63 . A method of operating a blood pressure measuring device comprising a host system and a detachable pressure sensor assembly with associated storage device having a first plurality of data stored within, the method comprising: 
 placing said sensor assembly in data communication with said host system, said host system having a second plurality of data associated therewith;    reading at least a portion of said first plurality of data from said storage device;    comparing said at least portion of said first plurality of data to at least a portion of said second plurality of data; and    determining whether said sensor assembly is enabled for measuring blood pressure based at least in part on said act of comparing.    
     
     
         64 . A method of evaluating the performance of a plurality of replaceable sensor assemblies each having a storage device associated therewith, and first data adapted to differentiate each sensor from at least a portion of said plurality, the method comprising: 
 operating each of said plurality of sensor assemblies;    generating second data resulting from said act of operating;    storing said second data; and    analyzing said second data from at least a portion of said plurality of sensor assemblies based at least in part on said first data associated therewith.    
     
     
         65 . The method of  claim 64 , wherein said act of operating comprises: 
 attaching each of said replaceable sensors to a host device; and    performing at least one verification of each of said sensor assemblies based at least in part on data stored in said storage device.    
     
     
         66 . The method of  claim 64 , wherein said act of generating second data comprises generating at least one of a plurality of possible error failure codes for said sensor assembly.  
     
     
         67 . The method of  claim 66 , wherein said act of storing said second data comprises storing said second data within said storage device for that sensor assembly.  
     
     
         68 . The method of  claim 66 , wherein said act of storing said second data comprises storing said second data within a storage device associated with a host device to which that sensor assembly is connected.  
     
     
         69 . The method of  claim 68 , further comprising aggregating second data from a plurality of ones of said host devices in order to perform said analyzing.  
     
     
         70 . The method of  claim 66 , wherein said second data comprises failure or error codes, and said act of analyzing comprises identifying one or more commonalities in said codes across multiple ones of said sensor assemblies.  
     
     
         71 . Replaceable sensor apparatus adapted for measuring at least one parameter associated with a living subject in concert with a host device, said detachable sensor assembly further comprising a storage device having a first plurality of data stored therein, said sensor assembly further being adapted for qualification according to the method comprising: 
 placing said sensor assembly in data communication with said host system;    reading at least a portion of said first plurality of data from said storage device;    creating a test condition within said sensor assembly;    determining at least one value relating to the operation of said sensor assembly relating to said test condition; and    determining whether said sensor assembly is qualified for measuring said at least one parameter based at least in part on said act of measuring.    
     
     
         72 . Replaceable sensor apparatus adapted for use with a host device and configured to prevent use thereof beyond a prescribed period of time according to the method comprising: 
 encoding first data within said sensor apparatus, said first data being representative of a first time;    placing said sensor apparatus in data communication with said host system;    measuring a second time using said host system;    comparing said first and second times using an acceptance criterion; and    disabling said sensor apparatus from further use if said criterion is not satisfied.    
     
     
         73 . Replaceable tonometric sensor apparatus adapted to preserve data integrity according to the method comprising: 
 collecting first data relating to at least one parameter associated with a living subject using said sensor apparatus;    analyzing said first data to generate a first estimate of said at least one parameter;    collecting second data relating to said at least one parameter using said sensor apparatus;    analyzing said second data to generate a second estimate of said at least one parameter;    comparing said first estimate and said second estimate using at least one acceptance criterion; and    storing at least one of said first data and said second data in a storage device if said at least one criterion is met.    
     
     
         74 . Tonometric disposable medical sensor apparatus adapted for use with a host device and having at least one pressure sensor and storage device associated therewith, said storage device containing both identifying and parametric information, said identifying and parametric information being used in cooperation by said sensor apparatus and host device to ensure that (i) said sensor apparatus is compatible with said host device; (ii) said sensor apparatus is functioning properly, and (iii) said sensor apparatus has not expired.  
     
     
         75 . The apparatus of  claim 74 , wherein said apparatus is further adapted to verify use on only one patient.