Donna,
I had the 2 most experienced nurses in the place looking/patting/trying--in the end, they gave me all the advice about keeping warm etc. and said to go home, rest, drink water and try again today!
It worked--first poke and I was 'up and running'---the cocktail was anyway!--and I feel more confident about next week's final 'bag' if I can just get this same vein we found back into good enough condition!
Sometimes it's the little things that get you down.......
Brenda