# US 7,611,483 B2 · Indicator metrics for infection monitoring > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,483 B2 - Document ID: US7611483B2 - Status: Granted - Kind: B2 - Application number: 11/737,180 - Filed: 2007-04-19 - Published: 2008-10-23 - Granted: 2009-11-03 - Earliest claimed: 2007-04-19 - Assignees: Medtronic, Inc. - Inventors: Martin T. Gerber; John C. Rondoni - Web page: https://patentgrep.com/patent/US7611483B2 ## CPC - A61B 5/01: Measuring temperature of body parts {; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue} (clinical contact thermometers G01K13/20) - A61B 5/0031: {Implanted circuitry} - A61B 5/076: {Permanent implantation} - A61B 5/145: Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06) - A61B 5/14539: {for measuring pH} - A61B 5/6846: {specially adapted to be brought in contact with an internal body part, i.e. invasive} - A61M 5/14276: {specially adapted for implantation} - A61M 5/16836: {by sensing tissue properties at the infusion site, e.g. for detecting infiltration} - A61N 1/37258: {Alerting the patient} - A61B 5/053: Measuring electrical impedance or conductance of a portion of the body - A61M 2205/18: with alarm - A61M 2205/3368: Temperature - A61M 2205/3523: using telemetric means - A61M 2205/3561: local, e.g. within room or hospital - A61N 1/36521: {the parameter being derived from measurement of an electrical impedance} - A61N 1/3756: {Casings with electrodes thereon, e.g. leadless stimulators} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A method for monitoring an infection in proximity to an implantable medical device includes monitoring an indicator of infection in proximity to an implanted medical device; determining whether the indicator crosses a first threshold indicative of infection for a first period of time; and issuing a first alert if the indicator crosses the first threshold for the first period of time. The method further includes determining whether the indicator crosses a second threshold indicative of infection for a second period of time. A value associated with the second threshold is less indicative of an infection than a comparable value associated with the first threshold. The second period of time is greater than the first period of time. The method further includes issuing a second alert if the indicator crosses the second threshold for the second period of time. The first and second alert may be the same or different. ## Claims ### Claim 1 A method for alerting that an infection is likely to be present in proximity to an implanted medical device, the method comprising: using the implanted medical device to monitor an indicator of infection in proximity to the implanted medical device; determining whether a metric of the indicator crosses a first threshold indicative of infection for a first period of time; determining whether the metric of the indicator crosses a second threshold indicative of infection for a second period of time, the second threshold being less indicative of an infection than the first threshold and the second period of time being greater than the first period of time; and issuing an alert if (i) the metric of the indicator crosses the first threshold indicative of infection for the first period of time, or (ii) the metric of the indicator crosses the second threshold indicative of infection for the second period of time. ### Claim 2 (depends on 1) The method of claim 1, wherein the first or second threshold is an absolute value metric. ### Claim 3 (depends on 1) The method of claim 1, wherein the first or second threshold is a percent deviation from a mean value metric. ### Claim 4 (depends on 1) The method of claim 1, wherein monitoring the indicator of infection comprises monitoring the indicator in discrete time intervals at a first frequency range. ### Claim 5 (depends on 4) The method of claim 4, further comprising: determining whether the metric of the monitored indicator crosses a third threshold for a third period of time; and increasing the frequency with which the indicator is monitored if the metric of the monitored indicator crosses the third threshold for the third period of time. ### Claim 6 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator of infection crosses the second threshold comprises comparing information regarding the indicator obtained in discrete time intervals. ### Claim 7 (depends on 6) The method of claim 6, wherein issuing the alert comprises issuing the alert if the indicator crosses the second threshold in consecutive discrete time intervals. ### Claim 8 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the first threshold for the first period of time comprises determining whether the metric of the indicator crosses the threshold for a predetermined percentage of the first time period, and wherein the alert is issued if the indicator crosses the first threshold for the predetermined percentage of the first time period. ### Claim 9 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the second threshold for the second period of time comprises determining whether the metric of the indicator crosses the threshold for a predetermined percentage of the second time period, and wherein the alert is issued if the metric of the indicator crosses the threshold for a predetermined percentage of the second time period. ### Claim 10 (depends on 1) The method of claim 1, wherein monitoring the indicator of infection comprises monitoring temperature in proximity to the implanted medical device. ### Claim 11 (depends on 10) The method of claim 10, wherein determining whether the metric of the indicator crosses the first threshold for the first period of time comprises determining whether the temperature at any given time is greater than 101° F. ### Claim 12 (depends on 11) The method of claim 11, wherein determining whether the metric of the indicator crosses the second threshold for the second period of time comprises determining whether the temperature is above 100° F. for two hours or more. ### Claim 13 (depends on 1) The method of claim 1, wherein monitoring the indicator of infection comprises monitoring pH in proximity to the implanted medical device. ### Claim 14 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the first threshold comprises determining whether the pH has deviated from a mean value by greater than 10%. ### Claim 15 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the second threshold comprises determining whether the pH has deviated from a mean value by greater than 5%. ### Claim 16 (depends on 1) The method of claim 1, wherein monitoring the indicator of infection comprises monitoring impedance in proximity to the implanted medical device. ### Claim 17 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the first threshold comprises determining whether the impedance has deviated from an average impedance value more than 30%. ### Claim 18 (depends on 1) The method of claim 1, wherein determining whether the metric of the indicator crosses the second threshold comprises determining whether the impedance has deviated from an average impedance value more than 20%. ### Claim 19 A computer readable medium comprising instructions that when implemented cause an implantable medical device to: monitor an indicator of infection in proximity to an implanted medical device; determine whether a metric of the indicator crosses a first threshold indicative of infection for a first period of time; determine whether the metric of the indicator crosses a second threshold indicative of infection for a second period of time, the second threshold being less indicative of an infection than the first threshold and the second period of time being greater than the first period of time; and issue an alert if (i) the metric of the indicator crosses the first threshold indicative of infection for the first period of time, or (ii) the metric of the indicator crosses the second threshold indicative of infection for the second period of time. ### Claim 20 (depends on 19) An implantable medical device comprising: the computer readable medium of claim 19; electronics capable of executing instructions of the computer readable medium; a sensor capable of detecting the indicator of infection and providing the electronics with information regarding the indicator; and an alarm operably coupled to the electronics and configured to provide the alert. ### Claim 21 (depends on 4) The method of claim 4, further comprising: increasing the frequency with which the indicator is monitored if the metric of the monitored indicator crosses the second threshold.