System for providing blood glucose measurements to an infusion device

This application claims priority from U.S. Provisional Applications No. 60/398,199 filed Jul. 24, 2002 and No. 60/412,998 filed Sep. 23, 2002, which are herein incorporated by reference.

This invention relates generally to infusion systems that are used for infusing a fluid into a user, and in particular, to apparatuses and methods for providing blood glucose measurements to an infusion device.

Patients with Type 1 diabetes and some patients with Type 2 diabetes use insulin to control their blood glucose (BG) level. Typically, if a patient\'s BG level is too high, the patient can inject a “bolus” (dose) of insulin to lower his/her BG level from its present level to a desired target level. Furthermore, patients may inject a bolus of insulin in anticipation of ingesting carbohydrates, thus heading off a sharp rise in their BG level. Patients employ various calculations to determine the amount of insulin to inject. Bolus estimation software is available for calculating an insulin bolus. Patients may use these software programs on an electronic computing device, such as a computer, the Internet, a personal digital assistant (PDA), or an insulin delivery device. Insulin delivery devices include infusion pumps, injection pens, and IV meters. The best bolus estimation software takes into account the patient\'s present BG level. Presently, a patient must measure his/her blood glucose using a BG measurement device, such as a test strip meter, a continuous glucose measurement system, or a hospital hemacue. BG measurement devices use various methods to measure the BG level of a patient, such as a sample of the patient\'s blood, a sensor in contact with a bodily fluid, an optical sensor, an enzymatic sensor, or a fluorescent sensor. When the BG measurement device has generated a BG measurement, the measurement is displayed on the BG measurement device. Then the patient may visually read the BG measurement and physically enter the BG measurement into an electronic computing device to calculate a bolus estimate. Finally, once the bolus estimate is calculated, the patient must inject the insulin bolus or program an insulin delivery device to deliver the bolus into their body. Unfortunately, this process is cumbersome and is subject to transcribing errors—for example, the patient may inaccurately enter the BG measurement that is displayed on the BG measurement device into the electronic computing device. Thus, if the BG measurement is not entered correctly, the bolus estimate is not accurate, which may lead to the delivery of an inappropriate insulin dose.

In preferred embodiments of the present invention, an infusion system for infusing a fluid into a body of a user includes a characteristic determining device and an infusion device. The characteristic determining device includes a housing adapted to be carried by the user, a receptacle coupled to the housing for receiving and testing an analyte from the user to determine a concentration of the analyte in the user, a processor contained in the housing and coupled to the receptacle for processing the determined concentration of the analyte from the receptacle, and a communication system contained in the housing and coupled to the processor for transmitting a communication including data indicative of the determined concentration of the analyte in the user. In particular embodiments, the characteristic determining device may also include a lancing device coupled to the receptacle for obtaining the analyte from the user. In preferred embodiments, the infusion device includes a housing adapted to be carried by the user, a drive mechanism contained in the housing and operatively coupled with a reservoir containing the fluid for infusing the fluid into the body of the user, a communication system contained in the housing for receiving the communication including the data indicative of the determined concentration of the analyte in the user from the determining device, and a processor contained in the housing and coupled to the communication system for processing the data indicative of the determined concentration of the analyte in the user and controlling the infusion device. The infusion device further includes a bolus estimator used in conjunction with the processor for calculating an estimated amount of fluid to be infused into the body of the user based upon the received data indicative of the determined concentration of the analyte in the user and a target concentration of the analyte in the user, and an indicator to indicate when the estimated amount of fluid to be infused has been calculated. Additionally, the infusion device may include a user input device for inputting an estimate of a material to be ingested by the user, and the bolus estimator may include the capability to calculate the estimated amount of fluid to be infused into the body of the user based upon the inputted estimate of the material to be ingested by the user. The infusion device may also include a memory for storing the data indicative of the determined concentration of the analyte in the user received by the infusion device communication system from the determining device communication system.

In particular embodiments, the characteristic determining device automatically transmits the communication including the data indicative of the determined concentration of the analyte in the user to the infusion device. In other particular embodiments, the characteristic determining device further includes a user input device for inputting commands, and transmits the communication including the data indicative of the determined concentration of the analyte in the user to the infusion device in response to a command from the user input device. In additional embodiments, the characteristic determining device further includes an indicator to indicate a status of the communication including the data indicative of the determined concentration of the analyte in the user being transmitted from the determining device communication system to the infusion device communication system.

In some embodiments, the communication transmitted from the characteristic determining device to the infusion device further includes a time at which the concentration of the analyte in the user was determined. In additional embodiments, the processor of the characteristic determining device determines an amount of time that has elapsed since the concentration of the analyte in the user was determined, and the communication transmitted from the determining device to the infusion device further includes the elapsed amount of time. Further, the processor of the characteristic determining device may cause the communication system of the characteristic determining device not to transmit the communication including the data indicative of the determined concentration of the analyte in the user if the elapsed amount of time exceeds a predetermined amount of time. In other embodiments, the infusion device processor determines an amount of time that has elapsed since the data indicative of the determined concentration of the analyte in the user was received, and causes the bolus estimator not to calculate the estimated amount of fluid to be infused based upon the determined concentration of the analyte if the elapsed amount of time exceeds a predetermined amount of time. In still other embodiments, the processor of the infusion device determines an amount of time that has elapsed since the concentration of the analyte in the user was determined, and causes the bolus estimator not to calculate the estimated amount of fluid to be infused based upon the determined concentration of the analyte if the elapsed amount of time exceeds a predetermined amount of time.

In further embodiments, the determining device communication system is capable of being deactivated and reactivated. The characteristic determining device includes a user input device for inputting commands, and the communication system of the characteristic determining device is capable of being deactivated in response to a first command from the user input device and being reactivated in response to a second command from the user input device. Alternatively, the communication system of the characteristic determining device may be automatically reactivated after a predetermined amount of time has elapsed or at a predetermined time of day. Additionally, the characteristic determining device may include a memory for storing data indicative of the determined concentration of the analyte in the user that is determined when the determining device communication system is deactivated, and the determining device communication system may transmit a communication including the stored data to the infusion device communication system when the determining device communication system is reactivated.

In still other embodiments, the processor of the characteristic determining device has unique identification information, and the communication transmitted from the characteristic determining device to the infusion device further includes the unique identification information of the determining device processor such that the infusion device is capable of discerning whether the communication is intended for receipt by the infusion device. In yet other embodiments, the processor of the infusion device has unique identification information, and the communication transmitted from the characteristic determining device to the infusion device further includes the unique identification information of the infusion device processor such that the infusion device is capable of discerning whether the communication is intended for receipt by the infusion device.

In preferred embodiments, the processor of the infusion device uses power cycling whereby power is periodically supplied to the communication system of the infusion device until a communication is received from the characteristic determining device. When a communication is received from the characteristic determining device, the processor of the infusion device discontinues using power cycling whereby the power is continuously supplied to the infusion device communication system. The infusion device processor may then resume using power cycling upon completing the receipt of the communication including the data indicative of the determined concentration of the analyte in the user from the determining device communication system.

In particular embodiments, the infusion system further includes a connector for coupling the characteristic determining device to a computer and downloading data from the characteristic determining device to the computer. The communication system of the infusion device is further capable of transmitting a communication including infusion device data to be downloaded, and the communication system of the characteristic determining device is further capable of receiving the communication including the infusion device data to be downloaded from the infusion device. The received infusion device data is then downloaded from the characteristic determining device through the connector to the computer. Alternatively, the characteristic determining device may further include a memory for storing data, and the received infusion device data may be stored in the memory of the characteristic determining device for subsequent downloading through the connector to the computer.

In other particular embodiments, the characteristic determining device further includes a user input device for inputting remote control commands for controlling the infusion device. The communication system of the characteristic determining device further transmits a communication including the remote control commands, and the communication system of the infusion device further receives the communication including the remote control commands from the characteristic determining device. The processor of the infusion device then controls the infusion device in accordance with the received remote control commands.

In yet other particular embodiments, the infusion device further includes a user input device for inputting remote control commands for controlling the characteristic determining device. The communication system of the infusion device further transmits a communication including the remote control commands, and the communication system of the characteristic determining device further receives the communication including the remote control commands from the infusion device. The processor of the characteristic determining device then controls the characteristic determining device in accordance with the received remote control commands.

In additional embodiments, the characteristic determining device further includes a determining device clock, and the infusion device further includes an infusion device clock. The infusion device communication system further transmits a communication including a time of the infusion device clock, and the determining device communication system further receives the communication including the time of the infusion device clock from the infusion device communication system. The determining device clock is then set to the received time of the infusion device clock. Alternatively, the determining device communication system further transmits a communication including a time of the determining device clock, and the infusion device communication system further receives the communication including the time of the determining device clock from the determining device communication system. The infusion device clock is then set to the received time of the determining device clock.

In accordance with another embodiment of the present invention, an infusion device infuses a fluid into a body of a user and is capable of communicating with a characteristic determining device, which is adapted for determining a concentration of an analyte in the user. The infusion device includes a housing adapted to be carried by the user, a drive mechanism contained in the housing and operatively coupled with a reservoir containing the fluid for infusing the fluid into the body of the user, a communication system contained in the housing for receiving a communication including data indicative of the determined concentration of the analyte in the user from the characteristic determining device, and a processor contained in the housing and coupled to the communication system for processing the data indicative of the determined concentration of the analyte in the user and controlling the infusion device. The infusion device also includes a bolus estimator used in conjunction with the processor for calculating an estimated amount of fluid to be infused into the body of the user based upon the received data indicative of the determined concentration of the analyte in the user and a target concentration of the analyte in the user. The infusion device further includes an indicator to indicate when the estimated amount of fluid to be infused has been calculated.

In accordance with still another embodiment of the present invention, a characteristic determining device determines a concentration of an analyte in a body of a user and is capable of communicating with an infusion device, which is adapted for infusing a fluid into the body of the user and calculating an estimated amount of the fluid to be infused into the body of the user based upon the determined concentration of the analyte in the user and a target concentration of the analyte in the user. The characteristic determining device includes a housing adapted to be carried by the user, a receptacle coupled to the housing for receiving and testing an analyte from the user to determine the concentration of the analyte in the user, a processor contained in the housing and coupled to the receptacle for processing the determined concentration of the analyte from the receptacle, and a communication system contained in the housing and coupled to the processor for transmitting a communication including data indicative of the determined concentration of the analyte in the user to the infusion device.

According to yet another embodiment of the present invention, an infusion system includes a characteristic determining device and an infusion device, and a method for infusing a fluid into a body of a user is provided. The method includes the steps of: receiving and testing an analyte from the user to determine a concentration of the analyte in the user, transmitting with the characteristic determining device a communication including data indicative of the determined concentration of the analyte in the user, and receiving with the infusion device the communication including the data indicative of the determined concentration of the analyte in the user. The data indicative of the determined concentration of the analyte in the user received by the infusion device from the characteristic determining device may then be stored in a memory of the infusion device. The method further includes the steps of calculating an estimated amount of fluid to be infused into the body of the user based upon the received data indicative of the determined concentration of the analyte in the user and a target concentration of the analyte in the user, and indicating when the estimated amount of fluid to be infused has been calculated. Additionally, the method may include the step of inputting an estimate of a material to be ingested by the user, and the estimated amount of fluid to be infused into the body of the user is calculated further based upon the inputted estimate of the material to be ingested by the user.

In some embodiments, the communication including the data indicative of the determined concentration of the analyte in the user is automatically transmitted from the characteristic determining device to the infusion device. In other embodiments, the communication including the data indicative of the determined concentration of the analyte in the user is transmitted from the characteristic determining device to the infusion device in response to an inputted command. In still other embodiments, the system indicates a status of the communication including the data indicative of the determined concentration of the analyte in the user being transmitted from the characteristic determining device to the infusion device.