title: Current induction in a fiberglass guidewire compared to conventional wires during simulated papillotomy.
abstract: BACKGROUND
  Current induced in a guidewire during papillotomy poses a danger of injury to the bile duct. We measured currents induced in three commercially available guidewires and a prototype fiberglass wire during simulated sphincterotomy under standard and nonstandard conditions.
  
  
  METHODS
  Blended current at 55 W was applied to a double-lumen papillotome grounded through a 1000 omega resistor. For extreme conditions, power was increased to 70 W using a single-lumen papillotome. Fault conditions were created with a break in the insulation at the distal end of each wire. Guidewire-induced current was measured, and safety calculations performed for adherence to accepted standards for electrosurgical devices.
  
  
  RESULTS
  Induced current was within safety limits for all wires tested under standard conditions. With insulation faults, one of the commercially available wires was unsafe. Under extreme conditions, with or without faults, the three commercial wires produced currents ranging from 9% to 225% above acceptable levels, while only the prototype wire remained safe.
  
  
  CONCLUSIONS
  Most guidewires contain metal cores that function as capacitors. Because its core is primarily fiberglass, the prototype wire generates less induced current under nonstandard conditions, thus achieving a greater margin of safety during wire-guided sphincterotomy.
authors.affiliation: Department of Medicine, Tufts University, School of Medicine, Boston, Massachusetts, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: O'Brien
authors.forename: S L
authors.initials: SL
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Connolly
authors.forename: E D
authors.initials: ED
authors.lastname: Libby
mesh_terms: D001652:Bile Ducts / Q000601:surgery*; D020698:Duodenoscopes; D004384:Duodenoscopy / Q000379:methods; D005898:Glass; D006801:Humans; D008953:Models, Anatomic; D012449:Safety; D016717:Sphincterotomy, Endoscopic / Q000295:instrumentation*
chemical_list: C009753:fiberglass