Venturi Vacuum Control for Oscillation-Free Surgical Suction
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Solution Overview
Problem
Venturi vacuum generators used in minimally invasive surgeries, such as vitrectomy, experience unstable vacuum pressure oscillations near maximum vacuum pressure, which can affect the efficiency, efficacy, and safety of surgical procedures by causing Intraocular Pressure (IOP) fluctuations.
Innovation Solution
A surgical system that includes a pressure source, shutoff valve, pressure regulator, venturi vacuum generator, throttle control proportional valve, vacuum pressure transducer, venturi inlet pressure transducer, and bleed control proportional valve, which work together to control flow and bleed vacuum pressure, thereby substantially preventing vacuum oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum pressure is increased to maximum level (670 mmHg), then suction power is maximized for efficient vitreous removal, but vacuum pressure oscillation occurs in the range of 550-670 mmHg causing IOP fluctuations
Solution Approach 1:
The system employs a vacuum pressure transducer to continuously monitor the vacuum pressure at the outlet of the venturi vacuum generator. The system controller receives this feedback signal and compares it with the desired vacuum level. When oscillation is detected or vacuum level deviates from the setpoint, the controller automatically adjusts the throttle control proportional valve to stabilize the vacuum pressure, ensuring continuous operation at maximum suction power without oscillation-induced interruptions.
Solution Approach 2:
The system dynamically changes the throttle valve opening parameter based on real-time vacuum pressure conditions. By adjusting the throttle control proportional valve, the system modifies the airflow parameter to the venturi vacuum generator, enabling operation at maximum vacuum pressure (670 mmHg) while preventing entry into the oscillation range (550-670 mmHg). This parameter adjustment allows maintaining optimal suction power without experiencing pressure oscillations.
2Reliability
If vacuum pressure is kept below the oscillation region (below 550 mmHg), then vacuum pressure stability is maintained, but suction power is reduced affecting surgical efficiency
Solution Approach 1:
The vacuum pressure transducer continuously monitors outlet pressure and provides feedback to the system controller. When the vacuum pressure approaches the oscillation region (550 mmHg), the controller receives this feedback and proactively adjusts the throttle control proportional valve to maintain pressure just below the oscillation threshold or stabilize it within the safe operating range, ensuring continuous stable operation without sacrificing necessary suction power.
Solution Approach 2:
The system performs preliminary action by detecting when vacuum pressure approaches the oscillation region and preemptively adjusting the throttle valve before oscillation occurs. This prevents the system from entering the unstable 550-670 mmHg range while maintaining vacuum pressure as high as possible below the oscillation threshold, thereby preserving suction power while avoiding oscillation.
3Productivity
If the surgeon ramps up vacuum prior to surgery to pass through the oscillation region, then maximum vacuum can be achieved, but surgical maneuvering must be halted during throttling through the oscillation region
Solution Approach 1:
The vacuum pressure transducer provides continuous feedback to the system controller during vacuum ramp-up. When the vacuum pressure approaches the oscillation region (550 mmHg), the controller automatically adjusts the throttle control proportional valve to stabilize pressure or maintain it just below the oscillation threshold. This allows the surgeon to ramp up vacuum continuously without halting surgical maneuvering, as the system autonomously manages the transition through the critical pressure range.
Solution Approach 2:
The system performs self-service by autonomously managing the vacuum pressure during ramp-up and operation. The system controller, using feedback from the vacuum pressure transducer, automatically adjusts the throttle valve to prevent oscillation without requiring surgeon intervention. This allows continuous surgical maneuvering while the system independently maintains stable vacuum pressure through the oscillation region.
4Device complexity
If a venturi vacuum generator is used to provide vacuum suction, then the system structure remains simple, but vacuum pressure oscillation occurs near maximum vacuum pressure
Solution Approach 1:
The system adds minimal complexity by incorporating a vacuum pressure transducer and system controller that provide real-time monitoring and automatic adjustment of the throttle valve. This feedback mechanism detects vacuum pressure oscillation and automatically corrects it by adjusting the throttle control proportional valve, maintaining stable vacuum pressure without requiring complete system redesign or complex mechanical modifications to the venturi vacuum generator.
Solution Approach 2:
The system replaces complex mechanical oscillation damping mechanisms with an electronic control system. Instead of using mechanical devices to physically dampen oscillations, the patent uses electronic sensors (vacuum pressure transducer) and controllers to detect and correct oscillation through automated throttle valve adjustment. This substitution maintains relative system simplicity while effectively eliminating vacuum pressure oscillation.
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 maintains stable vacuum pressure throughout the surgical procedure, preventing IOP fluctuations and ensuring continuous, efficient suction power without the need to halt the procedure.
Implementation Method 1
A venturi vacuum generator is provided in communication with the supply pressure to provide vacuum pressure to a suction port of the surgical system
Data Source
AI summary
Control methods for generating a venturi vacuum in a substantially oscillation-free manner for a surgical system. The control methods generally include utilizing real-time readings from a venturi vacuum generator inlet pressure transducer and a vacuum pressure transducer on the vacuum side of the venturi vacuum generator. These values may be employed in real-time to ascertain the emergence of an oscillation region on the vacuum side which may then be addressed by way of a bleed control proportional valve. When employed in combination with a throttle control proportional valve at the inlet side of the venturi vacuum generator, pressures may be manipulated in light of one another and/or individually as directed through a central controller. Thus, the presentation of oscillations on the vacuum side may be avoided to provide for a more stable vacuum supported surgical procedure.