title: Effect of bottle height and aspiration rate on postocclusion surge in Infiniti and Millennium peristaltic phacoemulsification machines.
abstract: OBJECTIVE
  To assess how flow and bottle height affect postocclusion surge in the Infiniti (Alcon, Inc.) and Millennium (Bausch & Lomb) peristaltic machines.
  
  
  METHODS
  John A. Moran Eye Center Clinical Laboratories, University of Utah, Salt Lake City, Utah.
  
  
  METHODS
  Postocclusion anterior chamber depth changes were measured in human eye-bank eyes using A-scan. Surge was simulated by clamping the aspiration tubing and releasing it at maximum vacuum. In both machines, surge was measured (1) with aspiration held constant at 12 mL/min and bottle heights at 60, 120, and 180 cm and (2) with bottle height held constant at 60 cm and aspiration rates at 12, 24, and 36 mL/min.
  
  
  RESULTS
  Surge decreased approximately 40% with each 60 cm increase in bottle height in the Infiniti. It was constant at all bottle heights in the Millennium. At 12 and 24 mL/min aspiration rates, surge in the Millennium was less than half that in the Infiniti (P<.001).
  
  
  CONCLUSIONS
  Postocclusion surge decreased linearly with increasing bottle height in the Infiniti system and was relatively constant with increasing bottle height in the Millennium system. The Millennium may offer a more stable phacoemulsification platform with respect to surge at a higher aspiration rate.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Ward
authors.forename: Dan
authors.initials: D
authors.lastname: Georgescu
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Olson
mesh_terms: D004322:Drainage; D006801:Humans; D006874:Hydrostatic Pressure; D018918:Phacoemulsification / Q000295:instrumentation*; D011312:Pressure; D014619:Vacuum Curettage