Heart rate and blood pressure effects of esmolol after ketamine induction and intubation

Abstract

Both ketamine and tracheal intubation are associated with increased heart rate (HR) and systolic blood pressure (SBP). Beta blockers prevent or attenuate this increase. Esmolol (E) is a new, intravenous, rapidly metabolized beta blocker. An open-label study was performed in 41 ASA Class II and III patients divided into groups 1-4: control, 100, 200, and 300 micrograms X kg-1 X min-1 (n = 10, 10, 11, and 10, respectively). E was infused over 10 min, the first one-fourth of which was a loading dose of 500 micrograms X kg-1 X min-1; at 4 min, ketamine was followed by succinylcholine, intubation, and enflurane-N2O-O2. HR, SBP, blood E, and plasma catecholamine levels were obtained during the 40 min of study. The control group had a baseline HR of 83 +/- 5 beats/min while esmolol groups 2-4 had an HR of 73 +/- 3, 72 +/- 3, and 68 +/- 4 beats/min, respectively (P less than 0.05). After ketamine, the control group HR increased to 93 +/- 6 beats/min and groups 2-4 remained at the baseline level, 73 +/- 3, 73 +/- 3 and 67 +/- 4 beats/min, respectively (P less than 0.05). Postintubation, the control increased further to 113 +/- 5 beats/min while groups 2-4 were significantly less, 91 +/- 5, 84 +/- 3, and 78 +/- 4 beats/min, respectively. The mean SBP in most E groups was less than the control within groups, but only in group 4 between groups was the SBP less at postintubation (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)