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Retractable Needle


Patients with end-stage renal disease are largely dependent on dialysis as renal replacement therapy. In haemodialysis, blood is passed through a membrane called a dialyzer, or artificial kidney ~3 times a week in order to filter out excess waste and water. The filtered blood is then returned to the body through the second needle. A hematoma (localized bleeding outside of blood vessels) resulting from incorrect needle cannulation if a very frequent problem. Major fistula infiltration occurs with ~5.2% of hemodialysis patient each year. Additionally, incorrect cannulation requires re-cannulation, which is both bad for the vessel, and results in discomfort for the patient. Moreover, 0.4% of all dialysis deaths are due to hematoma (Jose et al, 2017).

Technology Overview

A needle within a cannulation sheet has been designed that automatically retracts to a safe position when contact is made with the bloodstream. When the needle enters the vessel and blood enters the needle, a mechanism is activated which causes the needle to retract ‑ whilst leaving the sheet in place. Therefore, there is no opportunity to puncture the opposing vessel wall.


  • Hemodialysis access cannulation. 
  • Arterial line placement.
  • Pediatric venous cannulation.

Key benefits

  • The retractable needed would reduce the risk of hematoma, and the need of re-cannulation. 
  • The user doesn't have to retract the needle manually, resulting in more control over the needle in the blood stream.

Patent status

Patent filed.