Impedance-Based Needle Dislodgment Detection in Dialysis

The patent replaces visual monitoring (mechanical observation) with an electrical sensing system that uses electrical contacts and impedance measurement to detect needle dislodgment. This substitution enables automatic, continuous monitoring with high sensitivity and immediate response capability, resolving the contradiction between simple detection methods and precise detection requirements.

The patent uses blood itself as an intermediary conductor. Electrical contacts are placed in direct contact with the blood within the vascular access, allowing the blood to serve as the conductive medium that transmits electrical signals. This approach maintains patient safety while achieving high detection sensitivity, as the electrical pathway is established through the natural conductive properties of blood rather than requiring external contact with the needle.

The patent employs a single-use, disposable electrical contact device that is discarded after one use. The device is designed to be used once and then discarded, eliminating the need for sterilization and reprocessing. This self-service approach ensures that each device is sterile when new and is disposed of before any potential contamination can occur, thereby maximizing detection sensitivity while minimizing pathogen transmission risk.

The patent implements a feedback-based monitoring system where electrical contacts continuously measure impedance across the vascular access. The system automatically compares measured impedance values against baseline values and triggers an alarm when significant changes indicate needle dislodgment. This feedback mechanism enables continuous monitoring with immediate response capability while maintaining relatively simple device architecture, as the system only requires basic impedance measurement and comparison logic.