Nitrous oxide uptake in man: a new concept of uptake of inhalation anesthetics
Lin, C.-Y.
Acta Anaesthesiologica Taiwanica Official Journal of the Taiwan Society of Anesthesiologists 42(3): 127-134
2004
ISSN/ISBN: 1875-4597 PMID: 15551889 Document Number: 582633
With proper recognition of the functional residual capacity (FRC) and the existence of the alveolar membrane in consideration of gas uptake, the uptake of nitrous oxide does not follow the previously described power function of time, 1,000 ml x t(-1/2). By use of a simple subtraction method, nitrous oxide uptake was measured in patients undergoing anesthesia with nitrous oxide in oxygen and a high-dose narcotic for cardiac surgery. When FRC washin was considered separately, the uptake of nitrous oxide which started from zero, reached its peak value at the end of washin, and then diminished slowly. In contrast to previous publications, in which the time course of FA/FI was used to express the uptake of nitrous oxide, in spite of the area under the curve of FA/FI should not be used to express uptake, instead, the area above the curve, (1-FA/FI), fits the results and should be considered as representing uptake.