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Levels of Anesthesia Explained
Anesthesia is a spectrum, not an on/off switch. This is not a ranking of safety.
The American Society of Anesthesiologists describes sedation as a continuum, with levels defined by how a patient responds and how well they breathe on their own.
| Level | Responsiveness | Breathing and airway |
|---|---|---|
| Local anesthesia | Fully awake; the area is numb. | Unaffected. |
| Minimal sedation | Responds normally to speech. | Unaffected. |
| Moderate sedation | Responds purposefully to voice or light touch. | Usually adequate without help. |
| Deep sedation | Responds purposefully only after repeated or painful stimulation. | May need help to keep the airway open or to breathe. |
| General anesthesia | Not rousable. | Usually needs airway support, such as a breathing tube or mask device. |
Why it matters
Patients can move along the spectrum without planning to. Sedation that is intended to be moderate can become deeper. This is why an anesthesiologist who is focused on monitoring you is part of the pathway, and why the plan can change during surgery.
Who decides
Your anesthesiologist recommends the level after reviewing your health, the operation and your preferences. For some operations or health conditions, general anesthesia is the safer and more appropriate choice.
Explore your options at a consultation
References
- Law JA, Duggan LV, Asselin M, et al; Canadian Airway Focus Group. Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient. Can J Anaesth. 2021;68(9):1373-1404. PMID 34143394
- American Society of Anesthesiologists. Continuum of depth of sedation: definition of general anesthesia and levels of sedation/analgesia. (Professional society statement; not indexed in PubMed.)