Blood Pump Gas Detection and Pulsatile Ejection
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Solution Overview
Problem
Centrifugal pumps used in medical technology struggle with air accumulation, which leads to performance issues and potential damage due to air getting trapped in the rotor bearing, especially in blood pumps where increased flow rate regulation can exacerbate the problem.
Innovation Solution
Implementing a method to detect gas accumulation and briefly increasing pump speed to eject air bubbles, using sensors to measure gas presence and adjusting pump output to ensure air is removed without damaging the pump or the medium, with a pulsatile operation mode to facilitate air expulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump flow rate is increased to regulate to a specific flow rate, then the pump performance is improved, but gas bubbles accumulate in the rotor bearing area causing pump damage
Solution Approach 1:
The pump operates in pulsatile mode with periodic acceleration phases. During normal operation, the pump runs at a steady speed. When gas accumulation is detected, the pump briefly accelerates to a higher speed for a short duration (e.g., 1-5 seconds), then returns to normal speed. This periodic action prevents gas accumulation while maintaining overall pump performance and avoiding damage.
Solution Approach 2:
A gas detection system continuously monitors the pump for gas bubbles. When gas is detected in the rotor bearing area, the control system triggers a brief acceleration phase to expel the gas. After acceleration, the system continues monitoring to confirm gas removal before returning to normal operation. This feedback loop ensures reliable operation by responding to gas accumulation in real-time.
2Reliability
If the pump speed is briefly increased to expel air bubbles, then gas removal is achieved, but energy consumption increases
Solution Approach 1:
Instead of continuously operating at high speed to prevent gas accumulation, the pump uses partial action by briefly accelerating only when gas is detected. The acceleration duration is limited (e.g., 1-5 seconds), and the speed increase is applied only to the extent necessary to expel the gas bubbles. This approach achieves gas removal while minimizing energy consumption compared to continuous high-speed operation.
3Reliability
If gas detection is implemented to detect gas bubbles early, then gas accumulation is prevented, but device complexity increases
Solution Approach 1:
A gas detection device serves as an intermediary between the pump system and the control system. The detector monitors for gas bubbles in the rotor bearing area and transmits signals to the control unit, which then triggers appropriate acceleration phases. This intermediary component enables early gas detection and automated response while keeping the overall system architecture relatively simple and modular.
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
Effectively prevents air accumulation by detecting gas early and using brief power increases to expel air bubbles, maintaining pump performance and medium integrity, with a pulsatile operation that ensures air-free operation and reduces risk of damage.
Implementation Method 1
liquid is conveyed from an inlet to an outlet by a rotor
Implementation Method 2
specific centrifugal forces that not only propel the blood but also any gas accumulated in the blood pump radially outwards
Data Source
Figure 1~3
AI summary
The invention relates to a method for conveying blood or priming liquid as a medium using a blood pump, in which gas is measured in the medium in a feed line to the pump, in or on the pump, and the pump power is increased only for a short time as a function of the measured gas. The invention also relates to a blood pump, in particular a centrifugal pump or diagonal pump, comprising a rotor, a housing and a drive, said pump comprising a gas detector which acts upon the drive when gas is detected.