title: Axillary/subclavian vein puncture using navigation by parallax with an imaginary target.
abstract: BACKGROUND
  The parallax principles allow the relative positions of two overlapping objects with respect to the receiver of a two dimensional image to be determined, and can reliably navigate an object to a target in three dimensional space. Navigation by parallax can direct axillary/subclavian vein puncture under fluoroscopy with a guide wire inside the vein. The axillary/subclavian vein has a constant relationship with the first rib and an imaginary target just cranial and lateral to the middle part of the first rib may serve as a surrogate position marker for the vein adequate for guiding puncture.
  
  
  METHODS
  Patients requiring axillary/subclavian vein puncture were considered for the new technique. In an appropriate postero-anterior (P-A) caudal projection such that the middle part of the first rib lay outside the second rib concavity, the needle was inserted into the body medial to the coracoid process and advanced dorsally and medially towards an imaginary target cranial and lateral to the middle part of the first rib. Once the needle tip had reached the imaginary target, it was moved ventro-dorsally while staying stationary in the fluoroscopic image until venous blood was aspirated.
  
  
  RESULTS
  Navigation by parallax was successful in 21/24 cases (88%) and 42/45 separate venous punctures (93%) with an imaginary target, and in the remaining three cases with a real guide wire target. There were four insignificant axillary arterial punctures.
  
  
  CONCLUSIONS
  Navigation by parallax with an imaginary or a real target is effective, easy, and simple, and should facilitate axillary/subclavian vein puncture in multiple clinical scenarios.
authors: Royal Victoria Hospital, Belfast, UK. ernest.lau@btinternet.com
authors: Ernest W
authors: EW
authors: Lau
mesh_terms: D001367:Axillary Vein / Q000601:surgery*; D004567:Electrodes, Implanted; D005471:Fluoroscopy; D006801:Humans; D009339:Needles; D011183:Postoperative Complications; D011677:Punctures; D015641:Radiography, Interventional; D013350:Subclavian Vein / Q000601:surgery*