Nitrous oxide (N₂O) is often used for procedural sedation in settings such as dental offices, labor and delivery rooms, and outpatient surgical centers. Nitrous oxide is favored for its ability to relieve pain, ease of use, and rapid onset and recovery, which make it ideal for shorter, less invasive procedures. Its use is especially beneficial in situations where minimal airway manipulation is required, as it preserves spontaneous breathing and cardiovascular function, unlike deeper sedation methods that rely on intravenous agents. Nitrous oxide is frequently self-administered by patients during labor, allowing them to control their pain relief in real time.
However, nitrous oxide has its limitations, including an inability to deliver concentrations higher than 75% MAC under standard clinical conditions, which limits its effectiveness for more painful or invasive procedures. In locations without appropriate scavenging systems, the buildup of nitrous oxide may pose environmental and health risks. Despite these limitations, nitrous oxide remains a valuable tool for procedural sedation, thanks to its safety profile and ease of use.
| Clinical task | Agent or approach | Reason given |
|---|---|---|
| Inhalation induction in children | Sevoflurane | Pleasant odor and fast onset; avoids the anxiety and pain of intravenous induction; concentration is raised gradually over 30 to 60 seconds to minimize airway irritation and avoid laryngospasm or bronchospasm |
| Inhalation induction in adults | Sevoflurane | Chosen when spontaneous breathing must be preserved, such as difficult intravenous access, tracheal stenosis, or an obstructing airway mass |
| Agent to avoid for induction | Desflurane | More irritating to the airway and usually avoided for inhalation induction because of laryngospasm and bronchospasm risk |
| Rapid sequence induction | Not suited to inhalation induction | Onset is too slow for the quick airway control the technique requires |
| Supplementing intravenous agents | Volatile agents | Deepen anesthesia, blunt airway reflexes and the sympathetic response to laryngoscopy, and give dose-dependent muscle relaxation |
| Maintenance of general anesthesia | Sevoflurane, desflurane, or isoflurane | Dosed against minimum alveolar concentration and often combined with nitrous oxide, opioids, or sedative-hypnotics for a balanced technique |
| Rapid emergence | Desflurane or sevoflurane | Low blood-gas solubility allows faster elimination and recovery |
| Procedural sedation | Nitrous oxide | Analgesia with rapid onset and recovery while preserving spontaneous breathing and cardiovascular function |
