title: Estimation of heparin leak into the systemic circulation after central venous catheter heparin lock.
abstract: BACKGROUND
  Although most catheter problems in haemodialysis are related to infection or clotting, bleeding associated with the heparin lock is of clinical importance especially during peri-operative conditions. The objective of this in vitro study is to estimate the volume of heparin that may leak into the circulation immediately after performing a catheter lock.
  
  
  METHODS
  Different volumes (ml) of a dextrose solution were used to perform a catheter lock on haemodialysis catheters. The tip of the catheter was placed in a test tube containing water for a pre-specified period. The final concentrations of dextrose in the test tube were used to determine the volume of solution that leaked from the catheter.
  
  
  RESULTS
  When the total lumen volume was filled, the catheter leak was estimated to be 0.59+/-0.03 and 0.71+/-0.04 ml after 15 and 25 s, respectively. There was a continuous leak of 1.23+/-0.41, 2.20+/-0.34 and 3.38+/-0.23 ml at 5, 15 and 30 min, respectively, after performing a catheter lock on a catheter with a total lumen volume of 4.5 ml. The catheter leak was significantly reduced when only 3.7 ml of solution was used to fill the total lumen volume of 4.5 ml.
  
  
  CONCLUSIONS
  The present study demonstrates a significant early and late leakage from the catheter that occurs after performing a catheter lock. When applied to heparin, the volume of the unwanted catheter leak may result in adverse clinical events, especially following haemodialysis sessions and during peri-operative periods. However, these results are hypothesis-generating, and clinical studies are necessary to evaluate the efficacy of underfilling.
authors.affiliation: CHUQ-L'Hôtel Dieu de Québec Hospital, Division of Nephrology, Department of Medicine, Laval University, Québec, Canada. mohsen.agharazii@mail.chuq.qc.ca
authors.forename: Mohsen
authors.initials: M
authors.lastname: Agharazii
authors.forename: Isabelle
authors.initials: I
authors.lastname: Plamondon
authors.forename: Marcel
authors.initials: M
authors.lastname: Lebel
authors.forename: Pierre
authors.initials: P
authors.lastname: Douville
authors.forename: Simon
authors.initials: S
authors.lastname: Desmeules
mesh_terms: D002408:Catheters, Indwelling / Q000009:adverse effects*; D004867:Equipment Design; D005947:Glucose; D011189:Potassium Chloride; D006435:Renal Dialysis / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D011189:Potassium Chloride; D005947:Glucose