Determining Flow Rate in Venturi-Based System of Phacoemulsification
Purpose
Contemporary phacoemulsification (phaco) systems utilize two primary methods of generating vacuum, either peristaltic- or venturi-based vacuums. Venturi-based systems use vacuum to create flow. Unlike peristalic-based systems, the flow rates per vacuum level have yet to be determined venturi-based systems. This project set out to determine the flow rate in a venturi-based phaco system.
Methods
We conducted phaco experimentation with an Abbott Medical Optics (AMO, Santa Ana, CA, USA) Signature machine, which has the ability to switch between peristaltic and vacuum based outflow systems. For the first arm of the study, we used the Ellips FX handpiece to test flow using transversal ultrasonic modulation. For the second arm of the study, we utilized micropulsed longitudinal ultrasound with a duty cycle of 6ms on and 6ms off. Flow measurements were made by weighing the BSS bottle before and after runs in both peristaltic and venturi modes. Vacuum levels were set to either 300, 400, or 500mmHg.
Results
Flow rates were calculated by measuring the amount of BSS drained from the bottle after each run. At 300mmHg, flow rates averaged 77.7 ± 0.76 mL/min and 74.13 ± 0.8 mL/min in longitudinal and transversal arms, respectively. When increased to 400mmHg, flow rates increased to 90.4 ± 0.91 mL/min and 86.93 ± 0.12 mL/min in the longitudinal and transversal arms, respectively. Finally, increasing the vacuum to 500mmHg in venturi mode increase flow rates to 102.16 ± 2.25 mL/min and 96.6 ± 0.69 mL/min in the longitudinal and transversal arms, respectively.
Conclusion
This is the first study, to our knowledge, to quantify flow rates in venturi-based vacuum system. We have quantitatively demonstrated much higher flow rates in venturi mode compared to peristaltic mode using the AMO Whitestar machine.