Hypertension after epidural meperidine.

The use of epidural opiates, unlike the use of epidural local anaesthetics, is considered to have little, if any, effect on the cardiovascular system. A 76-year-old man with a flail chest injury was given a lumber epidural injection of meperidine. During the injection he suddenly complained of feeling cold, shivered vigorously and became tachypneic. His arterial blood pressure rose from 170/70 to 300/100; his pulse rate rose to 150/min. The patient was severely hypertensive for 40 minutes until treated with intravenous phentolamine. There is increasing evidence in the literature implicating the involvement of endogenous opiates in the central control mechanisms of blood pressure control.