Enflurane cardiovascular effects

Cardiovascular effects Most inhaled anesthetics decrease arterial blood pressure moderately. Enflurane and halothane are myocardial depressants that decrease cardiac output, while isoflurane causes peripheral vasodilation. Nitrous oxide is less likely to lower blood pressure than are other inhaled anesthetics. Blood flow to the liver and kidney is decreased by most inhaled agents. Halothane may sensitize the myocardium to the arrhythmogenic effects of catecholamines. 

In a study during open heart surgery, the cardiovascular effects of halothane, enflu-rane, methoxyflurane and fluroxene were compared (22C). The strongest cardiovascular depression was found after the use of halothane and enflurane. In a comparison of the 2 latter agents in equipotent dosages (23C) it was found that although the blood pressure decreased more markedly with enflurane, halothane caused significantly more myocardial depression. 

Karliczek, G., Hempelmann, G. and Piepen-brock, S. (1975) A comparison of tlic cardiovascular effects of enflurane, halothane, methoxy-flurane and fluroxene during open cardiac surgery./I efa ana est/r. belg., 26, 81. 

Unlike enflurane, isoflurane does not produce a seizurelike EEG pattern. Furthermore, the metabolic transformation of isoflurane is only one-tenth that of enflurane, so fluoride production is quite low. Among the halogenated hydrocarbons, isoflurane is one of the most popular, since it preserves cardiovascular stability and causes a low incidence of untoward effects. 

Inhaled anesthetics change heart rate either directly by altering the rate of sinus node depolarization or indirectly by shifting the balance of autonomic nervous system activity. Bradycardia is often seen with halothane, probably through vagal stimulation. In contrast, enflurane, and sevoflurane have little effect, and both desflurane and isoflurane increase heart rate. In the case of desflurane, cardiovascular responses include a transient sympathetic activation that can lead to marked increases in heart rate and blood pressure when high inspired gas concentrations are administered. 

Despite conflicting results, enflurane is generally considered to have httle effect on the cardiovascular system. Cardiac output was mildly influenced in healthy men and the negative inotropic effects of enflurane (2) were more pronounced in patients with congestive heart failure (3). Myocardial damage was suggested to be an unhkely comphcation of enflurane anesthesia, even in patients with ischemic heart disease (4). 

Cardiovascular System Enflurane causes a concentration-dependent decrease in arterial blood pressure, due, in part, to depression of myocardial contractility and peripheral vasodilation. Enflurane has minimal effects on heart rate. 

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