title: Impact of the shape of the needle tip on the efficacy of flushing implantable port chambers.
abstract: BACKGROUND
  To follow international guidelines and protect healthcare workers from needle stick injuries, manufacturers now provide safety non-coring needles.
  
  
  METHODS
  Numerical simulations show the potential efficacy of infusion and flushing flow in straight and curved side wall port chambers from a beveled non-coring needle (BNCN) or a bevel-free cannula (BFC).
  
  
  RESULTS
  In straight and curved side wall port chambers, the stream of flow with a BNCN is determined by the direction of the bevel, whereas the outlet stream from a BFC leads to a cylindrical symmetric flow. This, along with the position of the BFC impacts the wall shear rate of the port chamber, and the hydraulic resistance within the chamber.
  
  
  CONCLUSIONS
  This last factor has never been the subject of extensive hydrodynamic study. Caregiver safety and patient comfort are paramount but physics show that the shape of the needle tip affects the hydrodynamics of the injected flow.
  
  
  CONCLUSIONS
  The presence of a bevel at the needle tip is a key factor for ensuring efficient flushing of the port. The absence of a bevel may increase hydraulic resistance and deposits in the port chamber. Implantable port flushing protocols must take this notion into account if the patency of port chambers is to be maintained. The clinical impact of this study has yet to be determined.
authors.affiliation: Université Paris Diderot - Groupe Biofluidique, UMR CNRS, Paris - France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Guiffant
authors.affiliation: Pulmonary Department and Adult Cystic Fibrosis Centre, Cochin Hospital, Paris - France.
authors.forename: Christian
authors.initials: C
authors.lastname: Dupont
authors.affiliation: Université Paris Diderot - Groupe Biofluidique, UMR CNRS, Paris - France.|University Teaching Hospital Necker-Enfants Malades, Paris - France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Merckx
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D057446:Hydrodynamics; D007263:Infusions, Parenteral; D008422:Materials Testing; D009339:Needles; D009716:Numerical Analysis, Computer-Assisted; D013314:Stress, Mechanical; D007507:Therapeutic Irrigation / Q000379:methods*; D062666:Vascular Access Devices