Second Chance Automated External Defibrillator Pads

1. Second Chance Automated External Defibrillator Pads Defib Task Force (defibtaskforce@gmail.com) Lisa Jiang, Justin Lin, Joanna Nathan, Carl Nelson, Brad Otto Department of Bioengineering, Rice University Motivation Claiming 300,000 lives annually, sudden cardiac arrest (SCA) is among the leading causes of death in the US. SCAcan be caused by cardiac fibrillation, which is treated using Automated External Defibrillators (AEDs). AEDs administer an electric shock that resets the heart, returning it to its regular rhythm. This treatment option is only effective if administered within the first 10 minutes of SCA onset. Effective defibrillation depends on quick and accurate padplacement. Incorrectly placed pads do not deliver the electrical shock through the victim’s heart, and will fail to resuscitate the patient. Substituting the used pads with a new set placed in a different area can fix this problem, but most AED users will not know to do this, and the process itself requires too much time to complete. This increase in time to defibrillate the heart greatly decrease survival in SCA victims. Objective Defib Task Force aims to create the Second Chance AED Pads to allow untrained AED users to quickly change the shock vector if the initial AED shock fails. The design criteria are displayed below. Design Criteria • Testing and Modeling Vector Change • Purpose • Determine if device appliesthe desired • change in vector angle • Testing • Used six-electrode system, similar to an ECG • Measured voltage along two different vectors on porcine specimen • Matlab model inputs dimensions and distances between the electrodes and determines the three-dimensional angle change between the cardiac vectors for human and porcine models • Results • The porcine trial produced a 4° change in vector. • The Matlab program predicted a 5.8° change for the human model. • Conclusions • Second Chance AED Pads meet or exceed all design criteria. • Total cost: $83 to produce • Design significantly improves on control pad application success rate (100% vs. 60%) • Future Work • Test and optimize design • Animal trials • Clinical trials • Integrate switch design into AED systems • Include switch in verbal commands • Improved instructions • Acknowledgements • Defib Task Force would like to thank Dr. Renata Ramos, Dr. Mehdi Razavi, Dr. Maria Oden, Carlos Amaro, the Rice University OEDK, the Texas Heart Institute, and St. Luke’s Episcopal Hospital. • References • Deakin, Charles D. "European Resuscitation Council Guidelines for Resuscitation 2005 Section 3. Electrical Therapies: Automated External Defibrillators, Defibrillation, Cardioversion and Pacing." Resuscitation 67 (2005): S25-37. Print. • Bridy, Marie A., Thomas R. Burklow. “Understanding the newer automated external defibrillator devices: electrophysiology, biphasic waveforms, and technology”. J EmergNurs 2002;28:132-7. • Gundry, et al. "Comparison of Naive Sixth-Grade Children With Trained Professionals in the Use of an Automated External Defibrillator." Circulation 100 (1999): 1703-707. Print. Second Chance AED Pads • Dual electrode pad • Secondary cardiac vector in single pad unit • Decreases severity of skin burns • TwoElectrodes • 3 inches between centers of electrodes. • Each electrode on pad conducts. electricity only when manually selected by switch. Figure A: Pad Back The back of the pad consists of conducting electrode gel and metal plating. • Switch • Withstands high voltage and current • Resistant enough to prevent accidental flips • 101 Figure B: Switch Details The switch inside of the project box. The white wire is the main lead from the AED. The blue and green wires lead to the dual electrode pad. • Instructional Insert • Color-coded: • Aids placement • Orients pads/switch • Includes body landmarks to aid pad placement • Easy-to-follow Blue wire to electrode A Green wire to electrode B • Wiring • Plug connector is compatible with standard AED units. • Determining Pad Placement • Purpose • Determine optimal electrode separation distance on the dual pad • Test • Figure C: Pad placement survey. • Seven cardiologists completed surveys to determine optimal placement of the secondary electrodewith respect to the first pad. • Results • 3 inch displacement between electrode centers was determined to be the best displacement. • Testing Ease of Application • Purpose • Compare Second Chance AED pads to contemporary pads • Test • 65 untrained volunteers applied the Second Chance AED pads onto a mannequin, using pre-recorded voice instructions that simulate a realistic AED operation scenario. • Operation times and placement accuracy were recorded. • Results • Statistical analysis shows that the there is no significant difference between the times to first shock (α = 0.1, p = 0.3). Pad Orientation Pad Placement Pad Displacement