J Korean Pain Soc.  1994 Nov;7(2):181-187.

MAC of Enflurane Nalbuphine-Enflurane and ED50 of Fentanyl under 65% N20 in Rats

• Oh JG
• Lee WH
• Kim HJ

Abstract

The MAC (ED50)values of enflurane, fentanyl, and nalbuphine-enflurane under 65% N2O were determined in 76 Sprague-Dawley rats using the tail-clamp technique to compare the equipotent effects of intravenous and inhaled anesthetics. The rats were divided into 3 groups enfluarne, fentanyl, and nalbuphine-enflurane. Results were as follows: 1) The MAC value of enflurane under 65% NO was l.l6+/-0.05% and after subcutaneous nalbuphine 20 mg/kg injection, the values were I.08% at 60min and 0.99% at 90min. 2) The lowest ED50 for fentanyl was 26.8 microgram/kg at 15 min, and the ED 30, 45, and 60min after the injection were 36.2, 39.7, and 44.7 microgram/kg, respectively. 3) On arterial blood gas analysis under 65% N2O-1MAC (ED50), fentanyl and nalbuphine-enflurane groups showed mild increase in PaCO2, but there were no significant differences among 3 groups. Fentanyl group showed significant difference in pH compared with enfluarane and nalbuphine-enflurane groups. 4) Rats injected with high dose fentanyl (above 40 microgram) displayed rigidity and respiratory depression.

Keyword

MAC; ED50; Enfluarane; Fedtanyl; Nalbuphine; N2O

MeSH Terms

Anesthetics
Animals
Blood Gas Analysis
Enflurane*
Fentanyl*
Hydrogen-Ion Concentration
Nalbuphine
Rats*
Rats, Sprague-Dawley
Respiratory Insufficiency
Anesthetics
Enflurane
Fentanyl
Nalbuphine