Blood Pump Control Synchronizing Pulsatile Flow with Cardiac Cycle
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Solution Overview
Problem
Existing blood pump arrangements for extracorporeal circulatory support (ECLS) fail to effectively enhance coronary perfusion and systemic perfusion pressure, particularly in patients with cardiogenic shock or heart failure, where a pulsatile flow that synchronizes with the cardiac cycle is needed to improve oxygen supply to the heart.
Innovation Solution
A system that generates a wave-like pump output by converting a control signal into a pump drive signal, using a clock generator and EKG to synchronize pulsatile flow with the cardiac cycle, and optionally employing a second pump with a time-delayed wave output to superimpose pressure waves, ensuring both laminar and pulsatile flows to enhance perfusion pressure and oxygen supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a constant pump output is used for extracorporeal circulatory support, then systemic perfusion pressure is maintained with laminar baseline flow, but coronary perfusion and oxygen supply to the heart are insufficient
Solution Approach 1:
The patent applies periodic action by superimposing a pulsatile flow component on the constant baseline flow. The pump output varies periodically according to the formula Q(t) = Q_base + Q_pulse * sin(2*pi*f*t), where Q_base is the baseline flow and Q_pulse is the pulsatile component. This periodic variation synchronizes with the cardiac cycle to enhance coronary perfusion during diastole while maintaining overall systemic perfusion pressure.
2Reliability
If a pulsatile pump output is used to improve coronary perfusion, then oxygen supply to the heart is enhanced, but the complexity of the pump control system increases
Solution Approach 1:
The patent implements feedback control by using an ECG signal as input to dynamically adjust the pump's pulsatile output. The control system processes the ECG signal to detect R-waves and uses this information to modulate the pump motor drive signal, creating a feedback loop that synchronizes pump operation with the patient's native cardiac cycle. This reduces the need for complex mechanical modifications to the pump itself.
Solution Approach 2:
The patent replaces complex mechanical pulsatile pump mechanisms with a simpler rotary pump driven by a modulated motor. Instead of using mechanical valves, pistons, or other complex mechanical components to generate pulsatile flow, the invention uses electronic control of the motor drive signal to achieve the desired flow pattern, thereby reducing mechanical complexity and improving reliability.
3Stress or pressure
If the pump is synchronized with the cardiac cycle using ECG signal, then diastolic pressure is increased to improve coronary perfusion, but the precision of pulse timing control must be high
Solution Approach 1:
The system uses real-time ECG signal processing to provide feedback for precise timing control. The control unit continuously monitors the ECG signal, detects R-waves, and adjusts the pump activation timing based on the measured interval since the last R-wave. This feedback mechanism ensures that pulses are delivered at the optimal moment in the cardiac cycle, maximizing diastolic pressure enhancement while adapting to variations in heart rate.
Data Source
AI summary
An extracorporeal circulatory support device is further developed such that the pump drive signal causes a wave-like increase and decrease in pump output for a pulsatile flow. The pump is preferably a non-occlusive blood pump, such as a diagonal pump. In a preferred embodiment, the control signal is provided by an ECG. This makes it possible to increase the diastolic pressure to improve the oxygen supply to the heart muscle.