The blood–gas partition coefficient

Keywords: blood-gas partition coefficient, Ostwald coefficient, volatile anaesthetic, solubility


A partition coefficient (λ) describes the relative affinity of a volatile anaesthetic for two phases and how that anaesthetic distributes itself between the two phases when equilibrium has been achieved. The blood–gas partition coefficient (λb/g), or Ostwald coefficient for blood–gas, is a pharmacological term used to describe the solubility of a volatile anaesthetic agent. Volatile agents with a low blood–gas partition coefficient (less soluble) will exert a high partial pressure and produce a more rapid onset and offset of anaesthetic action.

Author Biography

E Bezuidenhout, University of the Witwatersrand

Department of Anaesthesiology, Charlotte Maxeke Johannesburg Academic Hospital, University of the Witwatersrand, South Africa

FCA 1 Anaesthetic Refresher Course 2020