And yet, every day, thousands of surgery patients get IV's inserted with no problems...
A few years back I read an article on the subject of inserting IV lines for execution. It seems these folks have collapsed veins from drug use, making it quite difficult to get the needle in.
The problem I see with this is if they were in prison for 10 to 20 years awaiting appeals, they should not have collapsed veins because they should not be getting drugs.
One person spent hours of agonizing torture where they tried every vein they could find. The governor then granted him life in prison instead of execution. Before he could get the news he died of a heart attack while they were still poking him.