Mechanical CPR Compression Timing for Better Cardiac Filling
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Solution Overview
Problem
Existing CPR systems and devices adhere to a 50:50 duty cycle without sufficient scientific evidence, leading to potential worsening of patient outcomes due to prolonged compression phases that prevent heart filling with blood during diastole.
Innovation Solution
Implementing a duty cycle with a shorter compression phase and a longer decompression phase, such as 35:65 to 45:55, to optimize blood ejection and filling times, using mechanical chest compression devices and feedback systems to adjust the duty cycle based on physiological criteria like aortic valve closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a 50:50 duty cycle is used in CPR systems, then the compression and decompression phases are equal in duration, but the compression phase is prolonged which prevents the heart from filling with blood during diastole
Solution Approach 1:
The patent changes the duty cycle parameter from the conventional 50:50 ratio to a 45:55 ratio, where the compression phase is 45% of the total cycle duration and the decompression phase is 55%. This parameter modification allows the heart to fill with blood during the extended decompression phase, improving cardiac output while maintaining effective compression.
2Force
If the compression phase is prolonged to ensure adequate compression depth, then blood ejection is improved, but the heart cannot fill with blood during diastole
Solution Approach 1:
The patent implements a dynamic duty cycle adjustment mechanism that monitors physiological parameters during CPR. The system dynamically adjusts the compression and decompression timing to optimize both compression force and blood filling, transitioning from a static 50:50 duty cycle to an adaptive 45:55 duty cycle that responds to real-time cardiac conditions.
3Quantity of substance
If a shorter compression phase is used to allow heart filling, then blood filling time is improved, but compression effectiveness may be reduced
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor cardiac output and physiological parameters during CPR. Based on this feedback, the system adjusts the duty cycle to maintain optimal compression effectiveness while ensuring adequate heart filling time. The feedback loop continuously optimizes the balance between compression force and blood filling.
4Reliability
If the decompression phase is extended to improve blood filling, then cardiac output is improved, but the overall CPR cycle time increases
Solution Approach 1:
The patent implements periodic action by maintaining a consistent 45:55 duty cycle rhythm that alternates between compression and decompression phases. This periodic pattern ensures that the heart fills with blood during each decompression phase while maintaining an efficient overall cycle time. The periodic action is optimized to balance blood filling with CPR effectiveness.
Data Source
AI summary
CPR systems and/or CPR devices that are configured to operate in association with a particular duty cycle are disclosed. An example mechanical chest compression device includes a processor(s) and a chest compressing mechanism configured to be disposed on a chest of a subject and to move for administering chest compressions to the subject. The processor(s) is configured to cause the chest compressing mechanism to move for administering the chest compressions to the subject over a series of compression-decompression cycles, wherein a compression-decompression cycle of the series of compression-decompression cycles includes a compression phase that is shorter than a decompression phase. The processor(s) is further configured to determine, during the compression phase, that a criterion is satisfied, and to cause the chest compressing mechanism to transition to movement that corresponds to the decompression phase in response to determining that the criterion is satisfied.