# US 7,147,615 B2 · Needle dislodgement detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,147,615 B2 - Document ID: US7147615B2 - Status: Granted - Kind: B2 - Application number: 09/888,154 - Filed: 2001-06-22 - Published: 2002-12-26 - Granted: 2006-12-12 - Earliest claimed: 2001-06-22 - Assignees: Baxter International Inc. - Inventors: Ramesh Wariar; Thomas P. Hartranft; Norm Cameron; Angel Lasso; Hector Caro - Web page: https://patentgrep.com/patent/US7147615B2 ## CPC - A61M 5/158: Needles {for infusions; Accessories therefor, e.g. for inserting infusion needles, or for holding them on the body} - A61B 5/15003: {for venous or arterial blood} - A61B 5/150503: {Single-ended needles (hollow piercing element tip design A61B5/150396)} - A61B 5/15087: {short range, e.g. between console and disposable (using implanted devices A61B5/150877)} - A61B 5/150961: {Means for the detection of the presence or absence of a module, a component or an abnormal condition; detection of leaks} - A61M 1/3656: {Monitoring patency or flow at connection sites; Detecting disconnections} - G01N 27/121: {for determining moisture content, e.g. humidity, of the fluid (moisture content of the tested material G01N27/048)} - G01N 27/223: {for determining moisture content, e.g. humidity (rain detectors on vehicle windows B60S1/0825)} - A61B 5/153: {Devices} specially adapted for taking samples of venous or arterial blood, e.g. with syringes - A61M 5/16831: {Monitoring, detecting, signalling or eliminating infusion flow anomalies (low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066)} - A61M 2005/1588: {having means for monitoring, controlling or visual inspection, e.g. for patency check or for avoiding extravasation} - A61M 2205/13: with means for the detection of operative contact with patient, e.g. lip sensor - A61M 2205/18: with alarm - 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)} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract An apparatus for detecting dislodgement of a needle inserted into a patient includes a sensor for detecting wetness due to blood and a sensor holder to secure the sensor to the patient such that the sensor detects wetness due to blood loss from the patient upon dislodgement of the needle. Methods and apparatuses for detecting, monitoring and/or controlling blood loss from a patient due to needle dislodgement are also provided. ## Claims ### Claim 1 An apparatus for detecting dislodgement of a needle inserted into a patient comprising: a sensor having a capacitive sensor, the capacitive sensor configured to detect wetness due to blood; and a barrier pad capable of absorbing blood lost from the patient due to the dislodgment of the needle; and a sensor holder configured to secure the sensor and the barrier pad adjacent to the needle, wherein the sensor holder secures the barrier pad between the sensor and the needle such that the sensor detects blood absorbed within the barrier pad. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the capacitive sensor includes one or more electrodes. ### Claim 3 (depends on 1) The apparatus of claim 1 wherein the capacitive sensor is located within the sensor holder such that the sensor detects wetness due to blood loss in the barrier pad. ### Claim 4 (depends on 1) The apparatus of claim 1 wherein the sensor produces a signal upon detection of blood loss. ### Claim 5 (depends on 4) The apparatus of claim 4 further comprising a control device adapted to receive the signal for monitoring and controlling blood loss due to the dislodgement of the needle during hemodialysis. ### Claim 6 (depends on 5) The apparatus of claim 5 wherein the control device is attached to the patient. ### Claim 7 (depends on 1) The apparatus of claim 1 wherein the needle comprises a venous needle. ### Claim 8 An apparatus for detecting needle dislodgement during hemodialysis comprising: a sensor holder having a cavity; a barrier pad configured to absorb blood lost from the patient due to the dislodgment of the needle; and a capacitive sensor comprising an electrode enclosed within the cavity of the sensor holder such that the capacitive sensor is positioned to detect wetness absorbed within the barrier pad from blood due to needle dislodgement during hemodialysis such that the capacitive sensor detects blood absorbed within the barrier pad. ### Claim 9 (depends on 8) The apparatus of claim 8 wherein the electrode comprises a single plate electrode. ### Claim 10 (depends on 8) The apparatus of claim 8 wherein the barrier pad overlies a vascular access region of a venous needle. ### Claim 11 (depends on 10) The apparatus of claim 10 wherein the sensor holder comprises a flexible material that adaptably conforms to the vascular access region such that the capacitive sensor is capable of detecting blood loss due to needle dislodgement. ### Claim 12 An apparatus for controlling blood loss from a patient during hemodialysis comprising: a barrier pad configured to absorb blood lost from the patient due to the dislodgment of the needle; a capacitive sensor configured to detect wetness due to blood; a sensor holder configured to secure the sensor and the barrier pad adjacent to the patient such that the sensor produces a signal indicative of wetness detected within the barrier due to blood loss from the patient upon dislodgement of a venous needle inserted into the patient wherein the capacitive sensor detects blood absorbed within the barrier pad; and a controller capable of processing the signal to prevent blood flow through the venous needle such that blood loss from the patient due to dislodgement of the venous needle is minimized. ### Claim 13 (depends on 12) The apparatus of claim 12 wherein the sensor holder comprises a pad configuration overlying an access region of the venous needle. ### Claim 14 (depends on 12) The apparatus of claim 12 wherein the barrier pad overlies an access region of the venous needle. ### Claim 15 (depends on 14) The apparatus of claim 14 wherein the sensor detects a change in a dielectric constant of the barrier pad. ### Claim 16 (depends on 14) The apparatus of claim 14 wherein the sensor is located inside of the sensor holder such that the sensor does not contact the sterile pad upon detecting wetness therein. ### Claim 17 (depends on 12) The apparatus of claim 12 wherein the controller is in communication with a hemodialysis machine via an electrical communication cable or a cordless interface to minimize blood loss due to venous needle dislodgement. ### Claim 18 (depends on 17) The apparatus of claim 17 wherein the controller is adapted to monitor one or more hemodialysis treatment parameters including wetness due to blood loss, change in blood flow and detection of arterial air bubbles during hemodialysis. ### Claim 19 (depends on 18) The apparatus of claim 18 wherein the controller is attached to the patient for electrical connection to the sensor. ### Claim 20 (depends on 18) The apparatus of claim 18 wherein the controller comprises a display for monitoring each of the parameters. ### Claim 21 A method of detecting needle dislodgement comprising the steps of: providing a barrier pad to absorb blood lost from the patient due to the dislodgment of the needle; and providing a capacitive sensor configured to detect wetness due to blood wherein the sensor detects blood absorbed within the barrier pad; inserting a needle into a patient; and securing the sensor and the barrier pad to the patient such that the sensor detects blood absorbed within the barrier pad on the patient upon dislodgement of the needle. ### Claim 22 (depends on 21) The method of claim 21 wherein the needle comprises a venous needle inserted into the patient for hemodialysis. ### Claim 23 A method of controlling blood loss from a patient due to needle dislodgement comprising the steps of: providing a capacitive sensor configured to detect wetness due to blood; providing a barrier pad to absorb blood lost from the patient due to the dislodgment of the needle; and inserting a needle into the patient; securing the sensor and the barrier pad adjacent to the patient such that the sensor produces a signal indicative of wetness within the barrier pad due to blood loss from the patient upon dislodgement of the needle and detects blood absorbed within the barrier pad; and processing the signal to prevent blood flow through the venous needle such that blood loss from the patient due to needle dislodgement is minimized. ### Claim 24 (depends on 23) The method of claim 23 wherein the needle comprises a venous needle inserted into the patient for hemodialysis. ### Claim 25 (depends on 24) The method of claim 24 wherein the signal is processed for communicating with a hemodialysis machine to minimize blood loss to the patient due to needle dislodgement. ### Claim 26 (depends on 25) The method of claim 25 wherein the signal is processed to shut-off a blood pump of the hemodialysis machine. ### Claim 27 (depends on 25) The method of claim 25 wherein the signal is processed to activate a venous line clamp for preventing blood flow via the venous needle. ### Claim 28 A method of providing dialysis to a patient comprising the steps of: providing a barrier pad; providing a capacitive sensor to detect wetness due to blood wherein the sensor does not contact blood upon detection thereof; inserting a venous needle into the patient; securing the sensor and the barrier pad in juxtaposition to the venous needle; passing blood through the venous needle via a hemodialysis machine; and detecting wetness within the barrier pad indicative of blood loss from the patient upon dislodgement of the venous needle such that the sensor detects blood absorbed within the barrier pad. ### Claim 29 (depends on 28) The method of claim 28 wherein blood flow through the venous needle is stopped upon detecting dislodgement of the venous needle such that blood loss from the patient is minimized.