Anesthetic uptake: Solubility coefficient

Pharmacology

Rate of uptake is dependent on 1) alveolar ventilation rate 2) partial pressure of gas  (concentration effect) **3) breathing system**

For poorly soluble anesthetic agents (ex. N2O, desflurane), an increase 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

66%

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2010

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