Marliss

I'm an older RN in Home Health. I initially worked in a hospital for 7 months, then in a SNF for 6 yrs before landing in my current job, which I love. The problem is that my infrequent blood draws (maybe one every 6 months) are only partially successful. I didn't do a lot of IV starts in any of my jobs, but at least I COULD start them without infiltration. I seem to be hitting the vein in the AC using either a butterfly or regular collection needle of either 21 or 22 gauge on the 1st attempt at least 75% of the time. But when I switch out the collection tube for a new one, the flow stops after only an inch or so. I have tried raising and lowering the angle of the needle. After that, I can't seem to start a new draw anywhere unless it is on a man with good veins. Information that would be helpful: 1) Should I remove the tourniquet before switching out the tubes or leave it on even if it takes more than one minute? 2) Any reference materials you can suggest? Thanks for any other suggestions.