Effect of remifentanil at various target plasma concentrations on hemodynamics during induction of general anesthesia with propofol

Objective To compare the effects of remifentanil at various target plasma concentrations on hemodynamics during induction of general anesthesia with propofol. Methods Sixty patients undergoing elective surgery were randomized to receive target-controlled infusion (TCI) of remifentanil of 2,4,or 6 ng / mL (group R2,R4,or R6,respectively; n = 20). After the blood-effect site concentrations of remifentanil were equilibrated,all the patients received TCI of propofol,with an increment of 0.50 μg / mL each time,until they were unconscious and received endotracheal intubation. In each group,SBP,DBP,and HR were monitored at pre-induction (T0); blood-effect site equilibration (T1); loss of eyelash reflex (T2); loss of consciousness (T3); the moment before intubation (T4); 1 min (T5),3 min (T6),and 5 min (T7) after intubation. Results As compared with T0,HR,SBP,and DBP in group R2 were decreased at T2 to T4 and increased at T5 significantly; HR in groups R4 and R6 was declined at T1 to T4 and T7,so were SBP and DBP at T2 to T7 (P 0.05 or P 0.01). As compared with group R2,HR at T1 to T2 and T5 to T7 was decreased in groups R4 and R6 (P 0.05),so were SBP and DBP at T5 to T7 (P 0.01). The incidence rates of bradycardia and muscle rigidity were more frequent in groups R4 and R6 than in group R2. Conclusions A remifentanil target concentration of 4 ng / mL in combination with propofol for induction of anesthesia can maintain stable hemodynamics and reduce responses to intubation and it has fewer adverse events.