Effect of high vacuum and aspiration on phacoemulsification efficiency and chatter using a transversal ultrasound machine

Abstract

To examine the role of high vacuum and aspiration settings on efficiency using a transversal ultrasound (US) machine. John A. Moran Eye Center Laboratory, University of Utah, Salt Lake City, Utah, USA. Experimental study. Porcine lens nuclei were incubated in formalin for 2hours and then cut into 2.0mm cubes. Phacoemulsification was performed using the Whitestar Signature machine. Settings were bottle height 50cm, on-time 6milliseconds, and off-time 6milliseconds. One hundred percent power was used for all 240 runs. Tested parameters were aspiration of 50mL/min and 60mL/min and vacuum of 500, mm Hg, 600mm Hg, and 650mm Hg. With continuous US, increasing aspiration from 50mL/min to 60mL/min significantly increased efficiency (23%). Increasing vacuum from 500mm Hg to 650mm Hg and from 600mm Hg to 650mm Hg significantly increased efficiency (20.2% and 13.6%, respectively). Higher vacuum and aspiration parameters did not influence the incidence of chatter events. In the micropulse US group, there was no significant efficiency increase with increasing vacuum or aspiration levels. There was a significant efficiency increase of continuous over micropulse US at an aspiration setting of 60mL/min and vacuum settings of 600mm Hg and 650mm Hg. As aspiration and vacuum increased, efficiency increased under continuous transverse US. No significant efficiency improvement occurred at high aspiration and vacuum settings under micropulse US. At 60mL/min aspiration and more than 600mm Hg vacuum, continuous power was significantly more efficient than micropulse transverse US.