Objective Comparison of Phacoemulsification Vacuum Systems
Modern phacoemulsification machines generate flow and vacuum via two mechanisms. Peristaltic systems use rollers to create flow-based vacuum especially when the tip is occluded. Venturi systems use vacuum to create flow and are not dependent on tip occlusion for vacuum, which may improve efficiency and chatter with decreased complication risk.
This is a laboratory-based in vitro comparative study of phacoemulsification vacuum systems. Porcine lenses were hardened with formalin and cut into 2 mm cubes. Pieces were randomly chosen and time to fragment removal (efficiency) and fragment bounces off the tip (chatter) were measured. Testing was undertaken using an Abbott Medical Optics Signature machine with the ability to switch between peristaltic and venturi-based vacuum. Multiple runs were performed using micropulsed longitudinal as well as transversal ultrasound.
Venturi statistically significantly improved efficiency over peristaltic vacuum with the transversal arm at all vacuum levels tested and decreased chatter at the higher vacuum levels. In the micropulsed longitudinal ultrasound arm, venturi was significantly more effective than peristaltic in terms of both efficiency at 300mmHg and 400mmHg and chatter at 300mmHg with the results at 500mmHg not significant for both efficiency and chatter. Aspiration flow rates for the transversal and longitudinal ultrasound were similar for the peristaltic runs. The flow rates were not statistically different for each ultrasound mode in venturi. Overall flow rates with venturi were much higher than measured for peristaltic.
Utilization of venturi-based vacuum, when available, may result in reduced clearance time of lens material and mitigate chatter especially at lower vacuum settings.