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Procedural sedation and day surgery
Sedation is a continuum from minimal to general anaesthesia; whoever gives sedation must be able to rescue the patient from one level deeper than planned, and must monitor including capnography in moderate and deep sedation.
Why it matters in the exam
The exam asks about the definitions of the sedation levels (minimal, moderate, deep, general anaesthesia) by response, breathing and cardiovascular function, the monitoring required, the synergy between midazolam and an opioid and their reversal, and the selection of patients for day surgery and discharge criteria — including an escort, driving and passing urine.
Under moderate sedation there is a purposeful response to voice or light touch, and the airway and breathing are adequate. In deep sedation the patient responds only to repeated or painful stimulation, and the airway may need support. In general anaesthesia there is no response even to pain. The combination of midazolam and fentanyl is stronger than the sum of its parts in depressing breathing; reversal: naloxone and flumazenil, with observation because their action is short. Propofol can quickly take a patient into deep sedation or anaesthesia, so it is given by someone who can manage the airway.
Most stable patients — ASA I to controlled III — suit day surgery when an adult escort is present for the first 24 hours. Age alone and BMI alone are not contraindications. Discharge requires stable vital signs, orientation, walking, pain and nausea under control and minimal bleeding; passing urine is not required for most patients, except after some spinal blocks and urological or pelvic surgery. After anaesthesia the patient does not drive or make important decisions for the first 24 hours. The common causes of unplanned admission after day surgery are pain, nausea and vomiting, bleeding and surgical complications — so an analgesia and antiemetic plan is set in advance.
Key points
- Four levels: minimal, moderate, deep, general anaesthesia.
- The provider must be able to rescue from one level deeper.
- Capnography in moderate and deep sedation.
- Midazolam and fentanyl — synergy in respiratory depression; short-acting reversal.
- Day surgery: a stable patient, an escort for 24 hours, no driving.
Summary table
| Level | Response | Airway and breathing | Circulation |
|---|---|---|---|
| Minimal | Normal response to voice | Unaffected | Unaffected |
| Moderate | Purposeful response to voice or light touch | No intervention needed | Usually maintained |
| Deep | Purposeful response only to repeated or painful stimulation | Support may be needed | Usually maintained |
| General anaesthesia | No response even to pain | Support often needed | May be impaired |
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Sources
- ASA Practice Guidelines for Moderate Procedural Sedation and Analgesia, 2018 — Levels of sedation, monitoring and reversal
- Association of Anaesthetists / British Association of Day Surgery guideline: Day case and short stay surgery, 2019 — Selection and discharge
- Miller's Anesthesia, 9th edition (2020) — Ambulatory (Outpatient) Anesthesia; Sedation and Monitoring
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.