Comparison of intubating conditions and hemodynamic responses to tracheal intubation with different effect-site concentrations of remifentanil without muscle relaxants during target-controlled infusion of propofol / 대한마취과학회지

BACKGROUND: We compared the effects of different remifentanil effect-site concentrations on intubating conditions, and cardiovascular and bispectral index score (BIS) responses to intubation at a fixed effect-site concentration of propofol without muscle relaxants. METHODS: Sixty-four patients were randomly assigned to one of three groups: remifentanil 2 (group R2, n = 22), 4 (group R4, n = 21), or 6 ng/ml (group R6, n = 21). Anesthesia was induced using target-controlled infusion of propofol 5 microgram/ml and each concentration of remifentanil. Laryngoscopy and intubation was attempted at 2.5 min following induction. Intubating conditions were assessed as excellent, good or poor using a standard scoring system. Mean arterial pressure (MAP), heart rate (HR), and BIS values were assessed. RESULTS: Excellent or good intubating conditions were obtained in 91% of group R4 and 95% of R6, both of which are higher compared with 32% of R2 (P < 0.01). MAP and HR decreased significantly after induction in all groups. After intubation, they recovered to baseline value in group R2 and R4 but were significantly less than baseline values in R6. BIS response to intubation was attenuated in group R4 and R6 but not R2. Hypotension was more frequent in group R6 than R2. CONCLUSIONS: Remifentanil target concentrations of 4 or 6 ng/ml combined with 5 microgram/ml propofol provided good or excellent conditions for tracheal intubation and prevented cardiovascular and BIS response during induction without muscle relaxants. However, the use of 6 ng/ml dose was associated with frequent occurrence of hypotension and bradycardia requiring treatment.

Maternal and neonatal effects of remifentanil used during induction of general anesthesia in preeclamptic patients undergoing cesarean delivery / 대한마취과학회지

BACKGROUND: Endotracheal intubation elicits cardiovascular and arousal responses. The present study was aimed to determine whether remifentanil affects these responses in patients with preeclampsia. METHODS: Thirty preeclamptic women who were scheduled to undergo cesarean delivery under general anesthesia were randomly assigned to receive either remifentanil 1 microgram/kg (n = 15) or saline (n = 15) before induction of anesthesia. Systolic arterial pressure (SBP), heart rate (HR) and bispectral index (BIS) value as well as plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar score and umbilical cord blood gas analysis. RESULTS: Induction with thiopental caused a reduction in SBP and BIS (P < 0.01) in both groups. Following the tracheal intubation SBP and HR increased in both groups, the magnitude of which was lower in the remifentanil group. BIS values also increased, of which magnitude did not differ between the groups. Norepinephrine concentrations increased significantly following the intubation in the control, while remained unaltered in the remifentanil group. The neonatal Apgar scores (5 min), and umbilical gas values were similar in the two groups except for higher incidence of Apgar score < 7 at 1 min in the remifentanil group. CONCLUSIONS: Remifentanil 1 microgram/kg effectively attenuates hemodynamic and catecholamine but not BIS responses to tracheal intubation in preeclamptic patients undergoing cesarean delivery. However, remifentanil may cause mild neonatal depression and thus should be used when adequate facilities for neonatal resuscitation are available.