Abstract
Low flow, closed technique for nitrous oxide anesthesia was reported. This technique is distinguished by the idea to supply only nitrous oxide into the anesthesia circuit for a certain minutes ("N2O minutes") to get expected inspiratory oxygen concentration.
Authors invented a theoretical formula to calculate above mentioned "N2O minutes", and compared the actual oxygen concentration at the end of "N2O minutes" with expected value in 138 patients. Oxygen concentration was measured by Gas-Liquid Chromatography.
The actual oxygen concentration was 31.67±8.07%, which agreed with expected value (30.0%) fairly well. Our low flow, closed technique is thought to be practical without specially prepared monitoring equipment.
