It has long been an admonition to students, residents, and practicing clinicians that epinephrine should never be used in areas of the body supplied by the fine terminal end arterioles such as the fingers and toes, penis, and nose. Theoretically, the epinephrine could cause prolonged spasm leading to ischemia and even necrosis of the tissue. This effect would be potentially magnified if the vessels were already diseased and narrowed, as occurs in smokers and patients with diabetes, peripheral vascular disease, and similar conditions. Hence, in the past, it was literally seen as substandard care to use epinephrine in these areas, especially when there was potential vascular disease or diminished blood supply.
In 2000, a series of articles began appearing in the literature to refute this “theoretical” adverse effect (see Bibliography). A paper by Denkler published in 2001 reviewed the literature from 1880 through 2000. The conclusion was: “An extensive literature review failed to provide consistent evidence that our current preparations of local anesthesia with epinephrine cause digital necrosis, although not all complications are necessarily reported. However, as with all techniques, caution is necessary to balance the risks of this technique.…”
Digits can withstand prolonged periods of ischemia. Successful reimplantations have been reported 42 hours after traumatic amputations.
The usual concentration of epinephrine in local anesthetics is 1 : 100,000. Studies have been conducted using concentrations of 1 : 1000 with virtually no adverse consequences.
A multicenter prospective study of 3110 consecutive cases of elective epinephrine use in the fingers and hands (concentration ≤1 : 100,000) found that “the true incidence of finger infarction in elective low-dose-epinephrine injection into the hand and finger is likely to be remote, particularly with the possible rescue with phentolamine. Phentolamine was not required to reverse the vasoconstriction in any patients” (Lalonde et al, 2005).
“Phentolamine rescue” or reversal of epinephrine is not discussed in this text. Nitroglycerin ointment has also been suggested to reverse any apparent ischemia, however rare (or even possible) this event is.
It would seem acceptable then to use local anesthetics with epinephrine to control bleeding for optimal wound repair and also to prolong needed anesthesia in areas supplied by end arteries. It would appear that an age-old caveat has been disproven. The prudent physician would still observe at-risk patients closely and use epinephrine sparingly.
