Between sevoflurane and halothane, which has the higher vapor pressure based on the provided values?

Between sevoflurane and halothane, which has the higher vapor pressure based on the provided values?

• A. Sevoflurane
• B. Halothane
• C. Isoflurane
• D. Desflurane

Answer: (B)

Vapor pressure is a measure of how readily a liquid evaporates into a vapor at a given temperature—the higher the vapor pressure, the more volatile the agent is. Between sevoflurane and halothane, halothane has the higher vapor pressure (roughly around 240–250 mmHg at room temperature) compared with sevoflurane (about 150–160 mmHg). That means halothane evaporates more readily and can reach a given inspired vapor concentration more easily under the same conditions. Therefore, halothane is the higher vapor pressure. For context, desflurane has an even higher vapor pressure, which is why it requires special vaporizer designs.

Vapor pressure is a measure of how readily a liquid evaporates into a vapor at a given temperature—the higher the vapor pressure, the more volatile the agent is. Between sevoflurane and halothane, halothane has the higher vapor pressure (roughly around 240–250 mmHg at room temperature) compared with sevoflurane (about 150–160 mmHg). That means halothane evaporates more readily and can reach a given inspired vapor concentration more easily under the same conditions. Therefore, halothane is the higher vapor pressure. For context, desflurane has an even higher vapor pressure, which is why it requires special vaporizer designs.