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Concentration effect

In the study of inhaled anesthetics, the concentration effect is the increase in the rate that the Fa(alveolar concentration)/Fi(inspired concentration) ratio rises as the alveolar concentration of that gas is increased. In simple terms, the higher the concentration of gas administered, the faster the alveolar concentration of that gas approaches the inspired concentration. In modern practice is only relevant for nitrous oxide since other inhaled anesthetics are delivered at much lower concentrations due to their higher potency.

See also


  • Korman B, Mapleson WW (May 1997). "Concentration and second gas effects: can the accepted explanation be improved?". Br J Anaesth. 78 (5): 618–25. doi:10.1093/bja/78.5.618. PMID 9175984.
  • Taheri S, Eger EI 2nd (September 1999). "A Demonstration of the Concentration and Second Gas Effects in Humans Anesthetized with Nitrous Oxide and Desflurane". Anesthesia and Analgesia. 89 (3): 774–80. doi:10.1213/00000539-199909000-00047. PMID 10475324.