Extracorporeal Circulator Motor Speed Control and Backflow Prevention
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Solution Overview
Problem
During extracorporeal circulation in cardiac surgery, the rotation speed of the motor in an extracorporeal circulator can inadvertently drop to a lower limit rotation speed or lower, leading to potential backflow of blood and posing a risk to the patient, as current counter devices do not effectively prevent such erroneous settings.
Innovation Solution
An extracorporeal circulator with a control unit and manipulation section that allows for changeable lower limit rotation speed settings, accompanied by a rotation speed display section to visually confirm and prevent the motor from dropping below the safe rotation speed, including a rotary manipulation section with an erroneous manipulation prevention mechanism to prevent accidental setting changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the lower limit rotation speed setting is made changeable to allow flexible adjustment, then the adaptability of the device is improved, but the risk of erroneous manipulation causing the rotation speed to drop to dangerous levels increases
Solution Approach 1:
The device applies preliminary anti-action by implementing a confirmation mechanism before allowing the lower limit rotation speed to be changed. When the rotation speed approaches the lower limit, the system requires explicit confirmation from the operator before permitting further reduction, thereby preventing erroneous manipulation that could cause the speed to drop to dangerous levels. This proactive measure counteracts potential human error before it can cause harm.
Solution Approach 2:
The device employs feedback by providing real-time display of the current rotation speed and the lower limit setting, along with visual or auditory warnings when the speed approaches the lower limit. This continuous feedback loop enables the operator to monitor the system state and take corrective action before erroneous manipulation occurs, while still allowing legitimate adjustments when needed.
2Ease of operation
If the rotation speed display section is provided to visually confirm the rotation speed, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The display section serves multiple functions: it shows the current rotation speed, displays the lower limit setting, provides visual warnings when approaching the limit, and confirms successful adjustments. By consolidating these multiple functions into a single display interface, the device achieves improved ease of operation without proportionally increasing complexity.
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
[Problem] Provided is an extracorporeal circulator in which extracorporeal circulation manipulation can be safely performed during a surgical operation while erroneous manipulation causing a rotation speed of a motor to drop to a lower limit rotation speed or lower is prevented in the extracorporeal circulator. [Solution] An extracorporeal circulator 1 includes a control unit 100, a manipulation section (for example, a rotary manipulation section 51) that is able to set a lower limit rotation speed setting value of a motor in a changeable manner, a rotation display section 60 that is able to display the lower limit rotation setting value of a motor 4 in accordance with a command of the control unit 100, and a display section 30. The lower limit rotation speed setting value is a minimum rotation speed for preventing backflow of blood inside a circulation circuit 1R when a manipulator performs a manipulation so as to operate the motor 4 and to cause the blood to return from an artificial lung 2 to an inside of a body of a patient P that is a patient while a command is applied to the control unit 100 so that a rotation speed of the motor 4 can be changed.