Adjustable Biphasic Defibrillator Waveform Tilt Control
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Solution Overview
Problem
External defibrillators face challenges in delivering effective biphasic shock waveforms across a range of patient impedances and myocardial cell responses, as they must be designed to work with various patient physiologies without prior specific adjustments, leading to inefficiencies and potential residual charges that can impede heart rhythm resumption.
Innovation Solution
An external defibrillator with adjustable biphasic pulse parameters, including energy, initial voltage, phase duration, and pulse tilt, utilizing a single capacitance and H-bridge circuit to dynamically adjust the second phase tilt by bypassing current during the second phase, ensuring the waveform terminates near zero volts, thus accommodating varying patient impedances and cell responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external defibrillators use fixed biphasic waveform parameters to work with various patients, then the device can be used on any patient without prior adjustments, but the treatment effectiveness decreases for patients with non-average impedance or cell response characteristics
Solution Approach 1:
The patent implements dynamic adjustment of the second phase tilt parameter based on real-time measurement of patient impedance and estimated myocardial cell response characteristics. The controller modifies the waveform parameters during operation rather than using fixed parameters, allowing the defibrillator to adapt to individual patient physiology while maintaining treatment effectiveness.
Solution Approach 2:
The system measures patient impedance during therapy and uses this feedback to adjust the second phase tilt parameter. This closed-loop control ensures that the waveform is optimized for the specific patient being treated, resolving the contradiction between universal applicability and treatment effectiveness.
2Reliability
If external defibrillators deliver high energy shocks to ensure effectiveness across all patients, then treatment effectiveness improves, but energy consumption increases and may cause unnecessary tissue damage
Solution Approach 1:
The patent dynamically changes the second phase tilt parameter based on measured patient impedance and estimated cell response characteristics. This allows optimization of energy delivery for each patient's specific physiology, delivering sufficient energy for effectiveness while minimizing excessive energy consumption and potential tissue damage.
3Device complexity
If external defibrillators use standard biphasic waveforms, then device complexity is reduced, but residual charges remain that can impede heart rhythm resumption
Solution Approach 1:
The system dynamically adjusts the second phase tilt parameter to optimize waveform termination. By controlling the tilt based on patient-specific measurements, the waveform can be shaped to terminate more effectively near zero volts, reducing residual charges while maintaining reasonable device complexity through software-based control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for effective defibrillation across a broad range of patient impedances and cell responses, minimizing residual charges and extending the range of effective waveform durations, thereby improving treatment efficacy and safety.
Implementation Method 1
utilizing a single capacitance and H-bridge circuit to dynamically adjust the second phase tilt by bypassing current during the second phase
Data Source
AI summary
A defibrillator produces a biphasic defibrillation pulse waveform with adjustable tilt for the second phase. The tilt of the second phase of the biphasic waveform can be controllably adjusted by selectively switching a current path which bypasses the patient during delivery of the second phase of the pulse. The inventive biphasic waveform can be delivered by a defibrillator with a single capacitance.