Purpose: To review the pharmacologic and pathophysiologic information neces
sary to-prescribe beta-blockers (BB) in perioperative medicine.
Data source: Manual retrieval and electronic research of the literature usi
ng MEDLINE (key-words: anesthesia and beta- blocker; surgery and beta-block
er).
Data synthesis: Cardioselective BB inhibit preferentially beta-1 receptors,
inducing a decrease in heart rate and cardiac inotropism leading to reduct
ion of oxygen myocardial consumption. Non-cardioselective BB inhibit also b
eta-2 receptors, increasing bronchial and peripheral vascular resistances a
nd uterine contractions. However, some BB are also vasodilators (carvedilol
, celiprolol, labetalol). Contraindications to BB result logically from the
ir pharmacological effects. Treatment with BB increases membrane beta-recep
tor density; this explains sympathetic overactivity observed during weaning
of treatment. Since the discovery of propranolol in 1964, the use of BB ha
s been controversial in anesthesia. Formerly, the adverse effects of partia
l sympatholysis during anesthesia and surgery were feared. However, since 1
973, experimental and clinical data have suggested a protective hemodynamic
effect.
Conclusion: Continued administration of BB up to the time of anesthesia has
been encouraged except in patients with signs of intolerance such as hypot
ension or excessive bradycardia.