Pain and sympathetic fibres are blocked first, motor fibres blocked later. So sympathetic blockade is very common with epidurals/spinals and peripheral blocks even with low concentration solutions. Once a threshold is reached, however, no further block occurs. I suspect this threshold is the same for sympathetic fibres as for pain fibres. Ie once you have acheived total analgesia with whatever solution you use, you have probably acheived maximal sympathetic blockade.
Hope this is clear enough. Why do you ask?
Hope this is clear enough. Why do you ask?