Inhaled anesthetics are frequently used to induce general anesthesia, particularly in certain patient populations like pediatric patients and adults with difficult airway conditions. In pediatric patients, inhalation induction is often preferred over intravenous induction to avoid the anxiety and pain associated with needles. This is particularly effective with agents like sevoflurane, which has a pleasant odor and fast onset, making it ideal for children. For adults, inhalation induction may be selected when maintaining spontaneous breathing is important, such as in patients with difficult IV access, tracheal stenosis, or masses that obstruct the airway. Although inhalation induction is less commonly used in adults due to the unpleasant odor of some anesthetics and a higher rate of postoperative nausea and vomiting (PONV), newer agents like sevoflurane have made this approach more tolerable.
During inhalation induction, the concentration of the anesthetic is gradually increased over 30 to 60 seconds to minimize airway irritation and avoid complications like laryngospasm or bronchospasm. Sevoflurane, with its smooth induction profile, is the agent of choice, while desflurane, which is more irritating to the airway, is usually avoided. The technique of overpressurization or co-administration of nitrous oxide can be used to speed up induction. However, due to the slower onset of inhalation induction, it is not suitable for rapid sequence induction and intubation, which requires quicker control of the airway.
