The use of epinephrine maybe?
There are also hypothetical problems with using epinephrine in large transplant sessions. One is that when the drug is infiltrated into the scalp over large areas, it may predispose to post-operative telogen effluvium (shedding). Another, potentially more serious problem, is that when adrenaline is added to an area whose blood supply is already compromised by a large number of recipient sites, the tissue may not receive enough oxygen. Although not proven, it is likely that epinephrine infiltration into the recipient area is a contributing factor in the development of the “central necrosis” that has occasionally been reported during hair transplantation. It is also possible that the intense vasoconstrictive action of epinephrine may contribute to decreased graft survival.
Either way if you get a transplant in a particular zone then future treatments could be used on the rest of the head, and a second pass of a transplant could provide enough density where you intially had work. I'm hoping the rest of the head will not be affected