Conditions under which subcutaneously injected epinephrine gives a hemodynamic effect.

Abstract

The statements in the literature regarding the hemodynamic effects of epinephrine injected hypodermically are few and conflicting. Some investigators 1 report feeble pressor effects; others 2 are as certain that there is no effect unless perchance epinephrine is injected quite directly and accidentally into a small venule. Even those who report feeble positive effects (Meltzer and Auer) were probably mistaken in the facts and interpretation, as we will point out more specifically in our detailed report.

In the course of some work in which epinephrine was administered subcutaneously in dogs under light paraldehyde (and morphine) anesthesia an appreciable rise of blood pressure was noted during the 3 to 4 minutes following the injection. Repetition of the experiments yielded questionable results; for there was either no immediate rise in blood pressure following such injection or the progressive rise in blood pressure could be readily explained on the basis of recovery from the light paraldehyde anesthesia of the animals. However, it was soon noticed that gentle massage of the injected area effected an appreciable hemodynamic effect and this led to a systematic investigation of the phenomenon.

Four to twelve kg. dogs were used for the most part under light paraldehyde anesthesia (1 to 1.5 cc. per kg.) reinforced as found necessary by subcutanecus injections of morphine sulphate (1/4 to 3/4 gr.). Blood pressure records were taken from the carotid artery. Hypodermic injections of epinephrine were made in a great many regions of the body in doses of 1/2 to 6 cc. (Parke Davis & Co.) in original dilution or more or less diluted with distilled water. In most instances the area so injected was gently or vigorously massaged immediately after injection and at various time intervals following injection.