The blood-gas partition coefficient

A partition coefficient (lambda) 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 (lambda(B/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.