title: Effect of ethanol/trisodium citrate lock on the mechanical properties of carbothane hemodialysis catheters.
abstract: OBJECTIVE
  The objective of this study was to investigate the effect of three locking solutions on the mechanical properties of carbothane hemodialysis catheters.
  
  
  METHODS
  Catheters were exposed in vitro to one of three locking solutions (heparin 5000 U/ml; 4% trisodium citrate (TSC) or 30% ethanol/4% TSC). Each solution was locked in six catheters and bathed at 37 degrees C for 9 weeks. Changes in the mechanical properties namely, force at break, elongation at break and elastic modulus of the catheters were determined by tensile testing.
  
  
  RESULTS
  The ethanol/TSC lock has an effect on the properties of carbothane hemodialysis catheters. The force at break was significantly lower in the ethanol/TSC group compared to the heparin and TSC groups (113.26 N, 191.97 N and 229.72 N, respectively, p < 0.01). Similarly, elongation at break was lower in the ethanol/TSC group, compared to the heparin and TSC groups (stretched 21.97, 38.29, and 42.42 times original length respectively, p < 0.01). The elastic modulus was not significantly different.
  
  
  CONCLUSIONS
  The effect of the ethanol/TSC lock on the catheters is unlikely to prohibit clinical use. After 9 weeks of exposure to the solution, the catheter segments could still be stretched to 22 times their length and withstand 11.5 kg (113 N) of force. Clinically produced forces during dialysis are many times smaller than the force required to break the catheters examined in this study. Therefore, the ethanol/TSC lock shows promise as a new catheter locking solution for the treatment of catheter-related infections. Further clinical studies are required.
authors.affiliation: Faculty of Pharmacy, University of Manitoba, Winnipeg, Canada.
authors.forename: A L
authors.initials: AL
authors.lastname: Bell
authors.forename: R
authors.initials: R
authors.lastname: Jayaraman
authors.forename: L M
authors.initials: LM
authors.lastname: Vercaigne
mesh_terms: D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D002408:Catheters, Indwelling / Q000009:adverse effects; D002951:Citrates; D000431:Ethanol; D006493:Heparin; D006801:Humans; D066298:In Vitro Techniques; D017053:Infection Control; D007239:Infections / Q000188:drug therapy / Q000209:etiology; D008422:Materials Testing; D011076:Polycarboxylate Cement; D011140:Polyurethanes; D006435:Renal Dialysis / Q000009:adverse effects / Q000295:instrumentation*; D000077559:Sodium Citrate; D012996:Solutions; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D002951:Citrates; D011076:Polycarboxylate Cement; D011140:Polyurethanes; D012996:Solutions; D000077559:Sodium Citrate; C005506:polycarbonate; D000431:Ethanol; D006493:Heparin