Esmolol attenuates tachycardia caused by tracheal intubation: a double-blind study

A new cardioselective and rapidly metabolized beta-blocker, esmolol (E), was given to prevent post-intubation tachycardia in 40 ASA Class PS I-II patients induced with thiopental, succinylcholine, N2O: O2 and enflurane sequence. The control group (A, n = 10) received 5% D/W. Three study groups received E loading doses of 500 micrograms/kg/min for 1 min (B, n = 8), 2 min (C, n = 10) and 4 min (D, n = 12); the continuous i.v. maintenance doses were 100, 200 and 300 micrograms/kg/min for a total of 10 min, respectively. The pre-esmolol heart rates were 85 +/- 4 in group A, 80 +/- 5 in B, 77 +/- 5 in C, 83 +/- 5 in D; at anesthetic induction and at 4 min after E-infusion, heart rates were 93 +/- 5, 65 +/- 4, 71 +/- 4, 70 +/- 5, respectively; three min post-intubation heart rates were in the control group 111 +/- 4 and 82 +/- 5, 93 +/- 5, 85 +/- 4, respectively, in the E-treated groups. Group A showed marked tachycardia (p less than or equal to 0.001) not observed in the treated groups B, C, D. A significant blockade of HR increases at all infusion rates of E (p less than or equal to 0.05) was found. E at all doses reduced the significant increase in BP observed in Group A. Catecholamine increases were identical and not significantly different among the groups. No adverse effects e.g. bradycardia, arrhythmias and hypotension caused by E or intubation were seen.(ABSTRACT TRUNCATED AT 250 WORDS)