second chance automated external defibrillator pads
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Second Chance Automated External Defibrillator Pads. Defib Task Force ([email protected]) Lisa Jiang, Justin Lin, Joanna Nathan, Carl Nelson, Brad Otto. Department of Bioengineering, Rice University. Motivation - PowerPoint PPT PresentationTRANSCRIPT
Second Chance Automated External Defibrillator Pads
Defib Task Force ([email protected])
Lisa Jiang, Justin Lin, Joanna Nathan, Carl Nelson, Brad OttoDepartment of Bioengineering, Rice University
MotivationClaiming 300,000 lives annually, sudden cardiac arrest (SCA) is among the leading causes of death in the US. SCA can 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 pad placement. 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.
ObjectiveDefib 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 CriteriaCriterion Test MetricPlacement Accuracy
Ease of Application Test
> 86% of pads placed correctly
Operation Time Ease of Application Test
<10 second increase in average application time
Switch Operation
Ease of Application Test
> 75% of participants flip switch
Durable Under High Voltage
Switch Durability Test
Switch can withstand 200J without malfunction
Secondary Pad Success
Vector Change Analysis
Switch successfully changes vector circuit
Significant Vector Change
Vector Change Analysis
>3 degree change in vector
Cost Effective Cost Analysis < $130 to produce
Second Chance AED Pads
Determining Pad PlacementPurpose 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 electrode with respect to the first pad.
Results 3 inch displacement between electrode centers
was determined to be the best displacement.
Testing Ease of ApplicationPurpose 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).
Testing and Modeling Vector Change
PurposeDetermine if device applies the desired change in vector angleTesting
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
o Animal trialso Clinical trials
Integrate switch design into AED systemso Include switch in verbal commandso Improved instructions
AcknowledgementsDefib 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 Emerg Nurs 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.
Test Group
Correct Placement
Switch Flipped
Time to 1st Shock
Time from Shocks 2-3
Control 60% N/A 79.2 s 149 s
SC Pads 100% 90% 88.0 s 149 s
Pad Placement
Pad Orientation
Pad Displacement
Switch Withstands high voltage and current Resistant enough to prevent accidental
flips
101
Wiring Plug connector is compatible
with standard AED units.
Figure A: Pad BackThe back of the pad consists of conducting electrode gel and metal plating.
Green wire to electrode B
Blue wire to electrode A
Figure B: Switch DetailsThe 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.
Dual electrode pad Secondary cardiac vector in single pad unit Decreases severity of skin burns Two Electrodes
o 3 inches between centers of electrodes.o Each electrode on pad conducts.
electricity only when manually selected by switch.
Instructional Insert Color-coded:
o Aids placemento Orients pads/switch
Includes body landmarks to aid pad placement
Easy-to-follow