Which inhalation agent has a blood gas partition coefficient of 0.42?

The inhalation agent characterized by a blood gas partition coefficient of 0.42 is desflurane. The blood gas partition coefficient is a critical factor that indicates how soluble a gas is in blood compared to the alveolar gas. A lower coefficient suggests that the agent is less soluble in blood, leading to faster induction and recovery times due to quicker transfer between the alveoli and the bloodstream.

In the case of desflurane, a lower blood gas solubility results in rapid onset and offset of anesthesia. This makes it particularly advantageous for outpatient surgery scenarios where quick recovery is essential. As desflurane has the lowest blood gas partition coefficient among the commonly used inhalation anesthetics, it allows for faster adjustments to anesthesia levels.

Other agents mentioned, like sevoflurane (with a higher blood gas partition coefficient), isoflurane, and halothane, have greater solubility in blood, resulting in longer induction and recovery times, thus serving different clinical purposes compared to desflurane.