Ultrasound tracking of medication delivery by medication injection devices

Abstract

A medication injection device includes a plunger head having an elastomer housing that fits within a barrel. The plunger head includes an ultrasonic transducer that sends and receives ultrasonic signals in the form of ultrasonic waves, an antenna, a microcontroller that interfaces with the ultrasonic transducer and the antenna, and a power source that powers the microcontroller and the ultrasonic transducer. The ultrasonic transducer, the antenna, the microcontroller, and the power source may be at least partially encapsulated in the elastomer housing. The microcontroller may be programmed to measure echo times of the ultrasonic waves, compare consecutive echo times, and apply a compensation factor. The microcontroller may also be programmed to calculate a volume of medication dispensed from the barrel.

1 . A machine-accessible storage medium providing instructions that, when executed by a medication injection device, will cause the medication injection device to perform operations comprising:
 sending ultrasonic signals as ultrasonic waves from a plunger head into a barrel of the medication injection device;   receiving reflections of the ultrasonic waves from the barrel;   measuring echo times of ultrasonic waves;   comparing consecutive echo times of the ultrasonic waves to determine a change in distance travelled by the plunger head;   assessing whether the change in distance is deemed to be indicative of an error;   applying a compensation factor to the change in distance when the change in distance is deemed to be indicative of the error; and   calculating a volume of medication dispensed from the barrel based on the change in distance of the plunger head, as compensated by the compensation factor when the change in distance is deemed to be indicative of the error.   
     
     
         2 . The machine-accessible storage medium of  claim 1 , wherein assessing whether the change in distance is deemed to be indicative of the error comprises:
 identifying when the change in distance is greater than or equal to about one wavelength of the ultrasonic waves.   
     
     
         3 . The machine-accessible storage medium of  claim 2 , wherein the compensation factor is equal to about one wavelength of the ultrasonic waves. 
     
     
         4 . The machine-accessible storage medium of  claim 1 , further providing instructions that, when executed by the medication injection device, will cause the medication injection device to perform further operations, comprising:
 determining that the change in distance is not indicative of the error when the change in distance is less than one wavelength of the ultrasonic waves.   
     
     
         5 . The machine-accessible storage medium of  claim 1 , wherein the ultrasonic signals have a frequency between about 2 Mhz and about 3 Mhz. 
     
     
         6 . The machine-accessible storage medium of  claim 1 , further providing instructions that, when executed by the medication injection device, will cause the medication injection device to perform further operations, comprising:
 starting to assess whether the change in distance is deemed to be indicative of the error only after the plunger head reaches a last 20% of a total available travel distance of the plunger head within the barrel.   
     
     
         7 . The machine-accessible storage medium of  claim 1 , further providing instructions that, when executed by the medication injection device, will cause the medication injection device to perform further operations, comprising:
 transmitting data indicative of the volume of medication dispensed from the barrel to a remote device via an antenna.   
     
     
         8 . The machine-accessible storage medium of  claim 7 , further providing instructions that, when executed by the medication injection device, will cause the medication injection device to perform further operations, comprising:
 registering a date and time the volume of medication is dispensed; and   transmitting the date and time to the remote device along with the data indicative of the volume of medication dispensed.   
     
     
         9 . The machine-accessible storage medium of  claim 1 , further providing instructions that, when executed by the medication injection device, will cause the medication injection device to perform further operations, comprising:
 measure a temperature of the volume of medication with a temperature sensor; and   compensating for changes in the temperature of the volume of medication when calculating the volume of medication dispensed.   
     
     
         10 . The machine-accessible storage medium of  claim 1 , wherein the medication injection device is at least one of a disposable syringe, an auto-injector, or an insulin pen. 
     
     
         11 . A method of tracking administration of a medication delivered by a medication injection device, the method comprises:
 depressing a plunger of the medication injection device;   sending and receiving ultrasonic signals in the form of ultrasonic waves from a plunger head installed within a barrel of the syringe;   measuring the echo times of the ultrasonic waves, wherein the echo time is the time it takes for an ultrasonic wave to travel through the medication to an end of a barrel, reflect, and return to the plunger head;   comparing consecutive echo times and if a change in distance corresponding to a change in the consecutive echo times is indicative of an error, the microcontroller applies a compensation factor to the change in distance; and   calculating a volume of the medication dispensed based on a distance the plunger head travels.   
     
     
         12 . The method of  claim 11 , wherein the change in distance corresponding to the change in the consecutive echo times is indicative of an error when the change in distance is greater than or equal to about one wavelength of the ultrasonic waves. 
     
     
         13 . The method of  claim 12 , wherein the compensation factor is equal to about a wavelength of the ultrasonic waves. 
     
     
         14 . The method of  claim 11 , further comprising identifying the change in distance corresponding to the change in the consecutive echo times as actual movement of the plunger head if the change in distance is less than one wavelength of the ultrasonic waves. 
     
     
         15 . The method of  claim 11 , further comprising selectively transmitting wirelessly the volume of the medication dispensed to a remote device. 
     
     
         17 . The method of claim  16 , further comprising registering the date and time the medication is dispensed and transmitting the date and time to the remote device along with the volume of medication dispensed. 
     
     
         18 . The method of  claim 11 , wherein the medication injection device is a standard disposable syringe, and the method further comprises installing the plunger head into the syringe prior to filing the barrel of the syringe with a medication. 
     
     
         10 . The method of  claim 11 , wherein the medication injection device is at least one of a disposable syringe, an auto-injector, or insulin pen. 
     
     
         20 . The method of  claim 11 , further comprising starting the comparing of consecutive echo times when the plunger head reaches the last 20% of a total available travel distance.