When you get a blood return, advance the needle just a tiny tiny bit, then thread the catheter over the needle. The needle is longer than the catheter. The catheter may not be in the vein yet when you retract the needle. Never get in a hurry and use plenty of saline, 10 cc's, to flush. Some shifts I hit them all and some shifts I hit them all. Try a warm blanket or washcloth over the site for a few minutes before you attempt. It's 2 sticks and you're out at our facility. Hope this helps.