Cardiac Assist Drive Pressure Profiling for Systolic and Diastolic Support
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Solution Overview
Problem
Existing cardiac assist systems face challenges in providing synchronized systolic and diastolic support to the heart, with diastolic assist often compromised by mechanical compression devices, and the need for a pump drive that can adapt to varying heart functions and maintain non-obligatory states for assessment.
Innovation Solution
A cardiac assist system with a displacement pump and variable valves to generate a customized pressure/flow profile, allowing for selective venting and fluid addition to achieve precise force application, and a suction line to maintain contact with the heart, controlled by a computer system to adjust for varying heart conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a direct cardiac compression device mechanically compresses the heart to aid systolic pump function, then systolic support is improved, but diastolic assist is compromised
Solution Approach 1:
The system dynamically switches between compression mode (for systolic support) and expansion mode (for diastolic support) based on the cardiac cycle phase. The direct cardiac compression device transitions from mechanically compressing the heart during systole to allowing expansion or applying outward force during diastole, enabling both functions to be performed effectively
Solution Approach 2:
The device applies periodic compression and expansion forces synchronized with the cardiac cycle. During systole, compression forces are applied to aid ventricular emptying; during diastole, expansion forces or reduced compression allow ventricular filling, creating a rhythmic pattern that supports both phases of cardiac function
2Speed
If pump drive pressure changes rapidly or with too much force to generate cyclic positive and negative pressures, then pumping rhythm control is improved, but device separation from the heart occurs
Solution Approach 1:
The system adjusts pressure parameters dynamically based on device attachment status. When separation is detected or anticipated, the pump drive modifies pressure change rates and magnitude to maintain attachment while still achieving effective cardiac compression and expansion. The vent valve timing and opening degree are adjusted to control pressure rise rates
3Measurement precision
If the heart's natural rhythm is followed for force application, then synchronization with heart pumping is improved, but adaptability to erratic or arrested heart function is reduced
Solution Approach 1:
The control system dynamically adapts the pumping profile based on real-time assessment of heart function. When the heart exhibits regular rhythm, the system synchronizes with the natural rhythm. When erratic or arrested function is detected, the system transitions to a non-synchronized mode with fixed timing and waveform parameters that are optimized for failing hearts
Solution Approach 2:
The system changes operational parameters including timing, duration, and magnitude of compression and expansion forces based on heart function assessment. For arrested hearts, the system applies forces at predetermined intervals with optimized waveforms that account for heart size, volume, and strain characteristics without relying on native rhythm
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
The system provides synchronized systolic and diastolic support, adapts to varying heart functions, and allows for non-obligatory states for assessment, enhancing heart recovery and functionality.
Implementation Method 1
The drive fluid has a pressure/flow profile that is customized to the needs of the heart... The pressure/flow profile is primarily generated by a displacement pump
Implementation Method 2
If the vent valve is vented to atmosphere, the pressure/flow of the drive fluid can be brought to atmospheric pressure
Implementation Method 3
The direct cardiac compression device may have a suction lead that is used to keep the direct cardiac compression device in contact with the heart
Data Source
AI summary
A system and method for assisting a heart in pumping blood, wherein the heart has external force requirements that need to be externally applied to the heart using a cardiac assist device that is powered by a drive fluid. The cardiac assist device is powered by a drive fluid having a pressure/flow profile that is customized to the needs of the heart. The pressure/flow profile is generated by a displacement pump. If the pressure/flow profile requires pressures that cannot be made by the displacement pump, then the pressure/flow profile can be altered by venting pressure and/or adding pressurized fluid into the system. In this manner, a precise pressure/flow profile can be produced that meets the exact needs of a heart being acted upon by a cardiac assist device.