Syringe Pump Occlusion Control with Volume-Aware Pressure Reduction
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Solution Overview
Problem
Syringe pumps face challenges in safely reducing internal pressure during occlusion events, particularly when the remaining medicinal solution volume is low, which can lead to unintended withdrawal of blood from patients.
Innovation Solution
Incorporating syringe diameter detection means and an occlusion management system that stores normal infusion pressures for different syringe volumes and types, displaying warnings for potential occlusions and stopping pressure reduction when the remaining volume is insufficient to prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal syringe pressure is reduced by driving the syringe plunger in a direction opposite to infusion, then the occlusion state is resolved, but blood may be drawn from the patient when the remaining medicinal solution volume is small
Solution Approach 1:
The syringe pump dynamically adjusts the occlusion detection level and pressure reduction control based on the real-time position of the syringe plunger and remaining medicinal solution volume. When the plunger position indicates low remaining volume, the system prevents aggressive pressure reduction that would cause blood withdrawal, while still resolving occlusions when sufficient volume remains.
Solution Approach 2:
The system changes the occlusion detection parameter (pressure threshold) based on the syringe plunger position and remaining volume. By adjusting the detection level dynamically according to volume conditions, the system distinguishes between normal pressure variations and true occlusions, preventing false occlusion detection and inappropriate pressure reduction that would harm the patient.
2Measurement precision
If the occlusion detection level is lowered to detect occlusions earlier, then occlusion detection sensitivity is improved, but false occlusion detection increases
Solution Approach 1:
The occlusion detection level is changed dynamically based on the syringe plunger position. When the plunger is at positions indicating sufficient remaining volume, a lower detection threshold enables sensitive occlusion detection. When the plunger position indicates low remaining volume, the detection threshold is raised to prevent false positives, thus resolving the contradiction between sensitivity and reliability.
Solution Approach 2:
The system transitions from static occlusion detection to dynamic detection that adapts to the current infusion state. The detection parameters are continuously updated based on plunger position feedback, enabling the system to maintain high sensitivity when appropriate while avoiding false detections during critical low-volume phases.
3Measurement precision
If the syringe pump continuously monitors internal pressure to detect occlusions, then occlusion detection accuracy is improved, but energy consumption increases
Solution Approach 1:
Instead of continuous pressure monitoring, the system uses periodic detection triggered by specific events (occlusion events detected during infusion). The pressure sensor monitors internal syringe pressure at intervals during infusion, and the control unit processes these periodic readings to detect occlusions, reducing energy consumption while maintaining detection accuracy.
Solution Approach 2:
The system uses the existing pressure sensor and infusion mechanism to self-diagnose occlusion conditions. The same components that drive the infusion also provide the data needed for occlusion detection, eliminating the need for separate continuous monitoring systems and reducing overall energy requirements.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
A syringe pump includes a syringe diameter detection means (103) for detecting a syringe volume, an accumulated quantity calculation means for calculating the accumulated quantity of infusion at the start of infusion, and an occlusion reduction means (116) for reducing the internal syringe pressure by driving a slider assembly (6) in a direction opposite to the infusing direction when an occluded state is greater than or equal to a specified value. When the syringe volume at the start of infusion is less than or equal to the accumulated quantity of infusion, the internal pressure reduction means is caused to stop reducing the internal syringe pressure.