Anesthetic uptake: Solubility coefficient

Rate of uptake is dependent on1) alveolar ventilation rate 2) partial pressure of gas(concentration effect)3) breathing system

For poorly soluble anesthetic agents (ex. N₂O, desflurane), anincrease in FA/Fi depends very little on alveolar ventilation. For soluble anesthetic agents (ex. isoflurane), an increase in FA/Fi depends significantly on alveolar ventilation.

Blood Gas Solubility Coefficient

• Halothane: 2.54
• Enflurane: 1.90
• Isoflurane: 1.46 (MAC 1.15%) – relatively dependent of alveolar ventilation rate
• Sevoflurane: 0.69 (MAC 2.1-2.6%)
• Desflurane: 0.42 (MAC 6-7.3%)
• N₂O: 0.46 (MAC > 760 mm Hg) – relatively independent of alveolar ventilation rate