Question
Rapid induction of anesthesia occurs with which of the following inhalation anesthetics?
| A. |
Isoflurane |
| B. |
Halothane |
| C. |
Desflurane |
| D. |
Sevoflurane |
Show Answer
|
Correct Answer » D Explanation |
 |
- The speed of induction with inhalational anesthetics primarily depends on the blood–gas partition coefficient.
- An anesthetic with a lower blood–gas partition coefficient equilibrates more rapidly between the alveoli and blood, resulting in faster induction and recovery.
- Sevofluranehas:
- A low blood–gas partition coefficient (~0.65).
- A non-pungent odor, making it well tolerated for inhalational induction, especially in children.
- Minimal airway irritation.
- Therefore, Sevoflurane is the inhalational agent of choice for rapid mask induction of anesthesia.
Why Other Options are Incorrect
A. Isoflurane
- Blood–gas partition coefficient ≈ 1.4.
- Slower induction than sevoflurane and desflurane.
- Pungent odor limits its use for inhalational induction.
B. Halothane
- Blood–gas partition coefficient ≈ 2.4.
- Slow induction due to higher blood solubility.
- Although non-pungent, it has largely been replaced because of its adverse effect profile.
C. Desflurane
- Blood–gas partition coefficient ≈ 0.42 (lowest among commonly used volatile agents).
- Has the fastest onset and recovery.
- However, it is highly pungent and irritates the airway, causing coughing, breath-holding, and laryngospasm.
- Therefore, it is not suitable for inhalational induction, especially in children.