Surgical Cassette Intraocular Pressure Control
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Solution Overview
Problem
Maintaining optimal intraocular pressure during ophthalmic surgery is challenging due to fluctuations caused by infusion and aspiration, leading to over-pressurization when aspiration lowers pressure, which is not clinically ideal.
Innovation Solution
A surgical cassette with dual infusion chambers, fluid level sensors, flow sensors, and a microprocessor that controls the infusion system to maintain desired intraocular pressure by switching between chambers and adjusting air pressure, ensuring consistent fluid supply and minimizing pressure drops during aspiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher dead head pressure is applied to compensate for pressure drops during aspiration, then intraocular pressure is maintained during aspiration, but the eye becomes over-pressurized when aspiration is not occurring
Solution Approach 1:
The system dynamically adjusts the infusion pressure in real-time based on whether aspiration is active. The microprocessor monitors aspiration flow and automatically modifies infusion pressure parameters, transitioning from a static high pressure setting to a dynamic adaptive pressure control system that optimizes for current surgical conditions.
Solution Approach 2:
The system implements feedback control by monitoring aspiration flow rates and using this information to adjust infusion pressure. The microprocessor receives data from flow sensors and continuously modifies infusion parameters to maintain optimal intraocular pressure, creating a closed-loop control system that prevents both over- and under-pressurization.
2Device complexity
If a single infusion chamber is used, then the device structure is simple, but the system fails when the chamber or fluid line becomes occluded
Solution Approach 1:
The infusion system is divided into multiple independent chambers (first and second infusion chambers) with separate fluid lines. This segmentation allows one chamber to remain operational while another is being flushed or replaced, ensuring continuous fluid supply and improving system reliability without requiring complete system shutdown.
Solution Approach 2:
The system prepares backup infusion chambers in advance that can be quickly activated if the primary chamber fails. The microprocessor monitors chamber status and automatically switches to备用 chambers or initiates flushing procedures before complete failure occurs, providing a safety buffer against fluid supply interruption.
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
The system effectively stabilizes intraocular pressure by dynamically adjusting the infusion rate and switching between chambers, preventing over-pressurization and ensuring continuous fluid supply, even when one chamber fails, thus enhancing surgical conditions.
Implementation Method 1
the enclosure is connected to a source of pressurized air by means of an adjustable valve and a pressure regulator, so that the pressure of the liquid contained in the cavity remains constant, independently of the flow-rate in the outlet pipe
Implementation Method 2
a flow sensor coupled to the enclosure and adapted to sense a flow-rate of the liquid through the outlet pipe
Implementation Method 3
a microprocessor coupled to the pressure sensor, the flow sensor and the pressure regulator and adapted to control the pressure regulator, the valve and the pump in order to maintain a desired pressure in the liquid supplied to the treatment site
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An improved surgical cassette for controlling intraocular pressure during ophthalmic surgery.