Comparison of the median effective concentration (EC50) and effect of sevoflurane with or without remifentanil in cesarean section with supreme laryngeal mask under narcotrend monitoring: a randomized trial.

BACKGROUND: Remifentanil combined with sevoflurane is a standard protocol for obstetric general anesthesia (GA). METHODS: In this study, we performed a randomized clinical trial to evaluate whether remifentanil has an effect on the median effective concentration (EC50) of sevoflurane and compare anesthetic outcomes of them in cesarean section with Supreme™ laryngeal mask airway (SLMA) under narcotrend monitoring. Ninety parturients with singleton births undergoing elective cesarean delivery (CD) with initial inhaled 1.0 minimum alveolar concentration (MAC) sevoflurane for anesthesia maintenance were assigned to three groups randomly and evenly: Group A (0.05 µg·kg-1·min-1 remifentanil combined with sevoflurane), Group B (0.1 µg·kg-1·min-1 remifentanil combined with sevoflurane), and Group C (normal saline combined with sevoflurane). Narcotrend was used to monitor the depth of anesthesia during the operation, with the level of anesthesia depth controlled within the D-E stage. The EC50 of sevoflurane was determined by Dixon's sequential method. The Narcotrend index, amount of bleeding, neonatal Apgar score, and corresponding treatment measures in the three groups were recorded. RESULTS: The results showed that the estimated EC50 of sevoflurane for obstetric GA was 0.80 MAC (95% CI: 0.63-0.95 MAC) in group A, 0.82 MAC (95% CI: 0.63-0.96 MAC) in group B, and 0.80 MAC (95% CI: 0.63-0.95 MAC) in group C. There was no statistically significant difference in the estimated EC50 of sevoflurane, time to wakefulness, Apgar score, amount of intraoperative bleeding, and postoperative bleeding within 24 hours between the three groups (all P>0.05). CONCLUSIONS: The addition of remifentanil at 0.05-0.1 µg·kg-1·min-1 did not change the EC50 of sevoflurane and anesthetic quality. The concentration of inhaled anesthetics can be minimized with Narcotrend monitoring. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000034512.

[Comparison of hemodynamic responses to orotracheal intubation with laryngeal mask airway CTrach™ and laryngoscope under general anesthesia].

OBJECTIVE: To compare the hemodynamic responses to orotracheal intubation with Laryngeal Mask Airway CTrach™ and Laryngoscope under general anesthesia. METHODS: 60 adult patients, scheduled for the elective gynecologic surgery under general anesthesia requiring the orotracheal intubation, were randomly allocated to either the CTrach (C) group or the Laryngoscope (D) group. After a standard intravenous anesthetic induction, the orotracheal intubation was performed. Noninvasive blood pressures and heart rates were recorded before (the baseline values) and after anesthesia induction(the postinduction values), at intubation and every minute for the first 3 minutes after intubation. RESULTS: The mean intubation time was longer in the C group than in the D group. The tracheal intubations caused significant increases in blood pressures and heart rates in the two groups compared to their postinduction values. In the D group, HR at intubation and after intubation were significantly higher Compared to the baseline values. In the C group, BP and HR at intubation and after intubation were not significantly different from the baseline values. BP and HR at intubation and after intubation were significantly higher in the D group than in the C group. CONCLUSION: The CTrach had advantage of attenuating the hemodynamic responses to the orotracheal intubation compared to the laryngoscope.