Circulatory effects of volatile anesthetic agents.

Modern general anesthesia includes the use of multimodal techniques, mixing volatile or intravenous agents with opioids and/or regional anesthesia. Therefore, most circulatory side effects of inhaled agents are seldom observed. They all produce dose-dependent decrease of systolic and diastolic function and depress baroreflexes to a varying degree. Desflurane, and to a much lesser degree, isoflurane, may cause sympathetic nervous system activation when inhaled concentration is rapidly increased to above 1.5 MAC. This appears to be the result of central activation rather than airway irritation. The older volatile anesthetics halothane and enflurane have no or minimal effect on coronary vascular tone. In contrast, the more recent agents all limit coronary vasodilator reserve by direct effect upon coronary resistance vessels, sevoflurane less than isoflurane and desflurane at equipotent anesthetic dose. Although isoflurane and desflurane appear to produce myocardial ischemia by non-hemodynamically related mechanisms more frequently than halothane or fentanyl in patients at risk, no particular agent has been identified to carry greater risk for adverse cardiac outcome than others.