Effect of Nitrous Oxide and Morphine on the Minimum Anesthetic Concentration of Fluroxene

Abstract

Fifty-one surgical patients were studied in 3 groups one anesthetized with fluroxene alone, a second with fluroxene preceded by premedication with morphine, and a third with fluroxene and nitrous oxide. The minimum anesthetic concentration of fluroxene required to prevent an overt muscular movement to a surgical incision was 3.4%. The preoperative use of 10-12 mg morphine reduced the minimum anesthetic concentration of fluroxene to 2.7% (a 20% reduction). Seventy-seven per cent inspired N2O reduced the minimum anesthetic concentration of fluroxene to 0.8% (a 76% reduction). The contribution of morphine in reducing anesthetic requirement was statistically significant (P <0.05). The reduction in fluroxene requirement by N2O to nearly one-fourth the amount when used alone significantly reduced cost and the flammability hazard.