Catheter-advancement actuated needle retraction system

A catheter and needle introducer assembly, comprising:

• a barrel having a length defining a barrel lumen and having a proximal end and a distal end, the distal end defining a distal wall with an opening extending therethrough, the barrel including a sidewall with a slot formed therethrough and extending along at least a portion of the length of the barrel;
• a catheter having a proximal end and a distal end;
• a catheter hub affixed to the proximal end of the catheter and located adjacent to the distal end of the barrel;
• an extension tube in fluid communication with the catheter;
• a needle having a sharp distal tip and a proximal end;
• a needle hub having a proximal end and a distal end affixed to the proximal end of the needle, the needle hub being disposed in the barrel lumen such that the sharp distal tip of the needle initially extends distally of the distal wall of the barrel through the opening coaxially within the catheter;
• a spring cooperating with the needle hub to urge the needle hub toward the proximal end of the barrel;
• a latch associated with the barrel to initially contact and hold the needle hub adjacent to the distal end of the barrel and to be movable to a position away from contact with the needle hub;
• and
• a tab affixed to the extension tube and extending through and slidably received in the slot in the barrel to engage the latch when the catheter is moved distally with respect to the barrel.