[Perioperative beta-blockers. Part one: fundamentals]

To review the pharmacologic and pathophysiologic information necessary to prescribe beta-blockers (BB) in perioperative medicine.

Manual retrieval and electronic research of the literature using MEDLINE (key-words: anesthesia and beta- blocker; surgery and beta-blocker).

Cardioselective BB inhibit preferentially beta-1 receptors, inducing a decrease in heart rate and cardiac inotropism leading to reduction of oxygen myocardial consumption. Non-cardioselective BB inhibit also beta-2 receptors, increasing bronchial and peripheral vascular resistances and uterine contractions. However, some BB are also vasodilators (carvedilol, celiprolol, labetalol). Contraindications to BB result logically from their pharmacological effects. Treatment with BB increases membrane beta-receptor density; this explains sympathetic overactivity observed during weaning of treatment. Since the discovery of propranolol in 1964, the use of BB has been controversial in anesthesia. Formerly, the adverse effects of partial sympatholysis during anesthesia and surgery were feared. However, since 1973, experimental and clinical data have suggested a protective hemodynamic effect.

Continued administration of BB up to the time of anesthesia has been encouraged except in patients with signs of intolerance such as hypotension or excessive bradycardia.