Effects of propofol on the minimum alveolar concentration of sevoflurane for immobility at skin incision in adult patients.
OBJECTIVE
To determine the effect of propofol on skin incision at target plasma concentrations of one to 6 μg/mL on the minimum alveolar concentration (MAC) of sevoflurane.


METHODS
Prospective, randomized, single-blinded study.


METHODS
Operating room of a university hospital.


METHODS
122 adult, ASA physical status I and II patients with cholecystitis and gastric cancer, presenting for elective abdominal surgery.


METHODS
Each group received propofol at different target-controlled plasma concentrations of 0, 1, 2, 3, 4, 5 and 6 μg/mL, respectively. The end-tidal concentration of sevoflurane was stable at a predetermined value for at least 15 minutes. Skin incision was performed after return of neuromuscular function.


METHODS
Patients were observed for gross purposeful movement for one minute after skin incision. Heart rate and mean arterial pressure were recorded before induction of anesthesia, before incision, and after incision.


RESULTS
The MAC of sevoflurane when used alone was 2.2% ± 0.11%. Propofol decreased the MAC of sevoflurane by 12.3% at one μg/mL, 30.5% at two μg/mL, 35% at three μg/mL, 46.8% at 4 μg/mL, 57.7% at 5 μg/mL, and 72.7% at 6 μg/mL. The linear regression equation of the interaction between sevoflurane and propofol was Y = 2.1679 - 0.256 X, R(2) = 0.9407, where X = plasma propofol concentration, Y = sevoflurane concentration, and R(2) = correlation coefficient.


CONCLUSIONS
Propofol decreases the MAC of sevoflurane in a concentration-dependent manner in adult patients.
Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, P. R. China.
Lin-Li
LL
Luo
Liang-Xue
LX
Zhou
Jian
J
Wang
Ru-Rong
RR
Wang
Wei
W
Huang
Jun
J
Zhou
D000328:Adult; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000493:pharmacokinetics*; D018686:Anesthetics, Intravenous / Q000493:pharmacokinetics / Q000494:pharmacology; D002764:Cholecystitis / Q000601:surgery; D004347:Drug Interactions; D017558:Elective Surgical Procedures / Q000379:methods; D005260:Female; D006785:Hospitals, University; D006801:Humans; D016014:Linear Models; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008875:Middle Aged; D015742:Propofol / Q000493:pharmacokinetics / Q000494:pharmacology*; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000378:metabolism*; D000077149:Sevoflurane; D016037:Single-Blind Method; D013274:Stomach Neoplasms / Q000601:surgery; D055815:Young Adult
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D000077149:Sevoflurane; D015742:Propofol