J Anesth Perioper Med. 2018;5(4):275-280. https://doi.org/10.24015/ebcmed.japm.2018.0115

Intravenous Administration of Ropivacaine Reduces Minimal Alveolar Concentration of Sevoflurane in Rats

Er-Ya Chen1, Hai Chen1, Cyrus Rastegar2, Chan Chen1, and Jin Liu1

From the 1Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; 2The Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA.

Correspondence to Dr. Chan Chen at xychenchan@gmail. com or Dr. Jin Liu at scujinliu@gmail.com.

EBCMED ID: ebcmed.japm.2018.0115 DOI: 10.24015/ebcmed.japm.2018.0115


Whether intravenous infusion of ropivacaine at a constant rate can affect the minimum alveolar concentration (MAC) of sevoflurane in rats and different concentration can produce different effects.

We used the Dixon “up-and-down” method to determine the MAC of sevoflurane in three groups (20 subjects per group). After a 30-minute equilibration, the medications (saline, 0.5% ropivacaine or 1.0% ropivacaine) were continuously infused at a rate of 0.5 mL/h/kg for 30 minutes, and the response to the supramaximal noxious stimulus was recorded (movement versus no movement).

The MAC was 2.34 ± 0.26% (95% confidence interval [CI], 2.22-2.46) in the saline group, 1.22 ± 0.31% (95%CI, 1.07-1.37) in the 0.5% ropivacaine group, and 1.06 ± 0.42% (95%CI, 0.86-1.26) in the 1.0% ropivacaine group. The MAC of the 0.5% ropivacaine (mean difference of 1.12% sevoflurane [95% adjusted CI, 0.86-1.38]; P < 0.01) and 1.0% ropivacaine groups (mean difference of 1.28% sevoflurane [95% adjusted CI, 1.02-1.54]; P < 0.01) were significantly lower than that of the saline group.

Intravenous administration of 0.5% and 1.0% ropivacaine both decreased the MAC of sevoflurane in rats, and 1.0% ropivacaine showed more decline. (Funded by the Distinguished Professorships Awards from the China Medical Board.)

Article Type
Original Article

Declaration of Interests
The authors have no other potential conflicts of interest for this work.

This study was supported by the Distinguished Professorships Awards (0082827601157, to Dr. Jin Liu) from the China Medical Board.

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