title: Elimination of infusion bubbles and uncontrolled reflux in the alcon constellation vitrectomy vision system.
abstract: OBJECTIVE
  To identify the sources and management of 2 problems associated with the Alcon Constellation Vitrectomy (Alcon Laboratories, Inc) System: 1) infusion bubbles and 2) uncontrolled reflux.
  
  
  METHODS
  Surgical and analytical videos were evaluated to identify the source of intraoperative bubbles, which localized to the duckbill valve (DV). Intraoperatively, the authors modified the infusion tubing and its control by removing the DV. The DV was repurposed as a one-way valve to block reflux originating from the vitrectomy console.
  
  
  RESULTS
  Twenty consecutive 23-gauge vitrectomies in 20 eyes of 20 subjects from 2 surgeons (S.R.R. and E.H.S.) were reviewed. Infusion bubbles at the DV developed with each transitory tubing pressure drop upon opening of the infusion clamp. Removal of the DV from the infusion line eliminated infusion bubbles in 20 consecutive 23-gauge cases. Adding a one-way valve, which was fashioned from the DV, to the aspiration tubing, resulted in elimination of infusion bubbles and console-originated reflux in 20 eyes. Placement of the DV to block reflux eliminated both uncontrolled and purposeful console-originated reflux.
  
  
  CONCLUSIONS
  Intraoperative modification of Constellation tubing may eliminate two potentially harmful problems until manufacturer correction is instituted. Because the authors' modified connections represent off-label connectivity, the manufacturer cannot contact potentially affected surgeons or suggest temporary alternative connectivity improvements.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa 52242, USA. stephenrussell@uiowa.edu
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Russell
authors.forename: Elliott H
authors.initials: EH
authors.lastname: Sohn
authors.forename: H Culver
authors.initials: HC
authors.lastname: Boldt
authors.forename: James C
authors.initials: JC
authors.lastname: Folk
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Tarantola
authors.forename: Christine N
authors.initials: CN
authors.lastname: Kay
authors.forename: Vinit B
authors.initials: VB
authors.lastname: Mahajan
mesh_terms: D005740:Gases; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D045423:Microbubbles / Q000009:adverse effects*; D012167:Retinal Perforations / Q000209:etiology / Q000517:prevention & control*; D014741:Video Recording; D014821:Vitrectomy / Q000295:instrumentation*; D057586:Vitreoretinal Surgery
chemical_list: D005740:Gases