The circulatory effects of intravenously administered ephedrine during epidural blockade.

The changes in central circulation following a small dose of intravenously administered ephedrine were studied in middle-aged and elderly patients during high epidural blockade with bupivacaine 0.5% with adrenaline, etidocaine 1% with adrenaline, and etidocaine 1% plain. Itravenously injected ephedrine restored the mean, systolic and diastolic arterial blood pressures to the preanalgesic value independent of the degree of hypotension, and was not followed by marked hypertension in any case. Although the heart rate did not change, the cardiostimulatory effects were more pronounced than after subcutaneous premedication, resulting in increased stroke volume and cardiac output in all groups. Peripheral vascular resistance increased to the preanalgesic value in the groups receiving bupivacaine adrenaline and etidocaine plain. In the etidocaine adrenaline group, peripheral vascular resistance was little changed, as the cardiostimulatory effects were more pronounced than in the other groups.