[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anaesthesia and ICU](https://durgical.com/en/anaesthesia/) › [Recovery and pain](https://durgical.com/en/anaesthesia/areas/recovery/) › The recovery unit: monitoring and discharge criteria

# The recovery unit: monitoring and discharge criteria

- Concept

After an operation, patients wake up in a recovery unit where nurses and doctors watch breathing, circulation, pain and nausea until it is safe to move on.

Updated Nov 13, 2026

## Key points

- The most common serious recovery problems are airway obstruction and hypoxaemia; continuous pulse oximetry and an immediately available anaesthetist are standard.
- Handover from anaesthetist to recovery nurse is structured: patient, procedure, anaesthetic, events, fluids and losses, and the plan for pain, nausea and oxygen.
- Modified Aldrete score: activity, respiration, circulation, consciousness and oxygen saturation, each scored 0 to 2; a total of 9 or more usually allows leaving phase I.
- Discharge is based on criteria, not a fixed time; day-case patients go home with a responsible adult and written instructions.
- Residual neuromuscular blockade causes weakness, airway obstruction and aspiration; it is prevented by quantitative monitoring and full reversal before extubation.

On this page

- The basics Key points
- What it is
- Key points
- Components
- How it works
- Step by step
- Modified Aldrete score (each item 0 to 2)
- In practice
- Next step
- Elsewhere in DurgiPedia

- Study Test yourself

- Connections Connections

## What it is

The post-anaesthesia care unit (PACU), or recovery room, is where patients are watched closely while the effects of anaesthesia and surgery wear off. Emergence is a time of real risk: residual anaesthetic, opioids and muscle relaxant can depress breathing and airway tone, and pain, nausea, shivering, bleeding and changes in blood pressure all tend to appear in the first hour. Care begins with a structured handover from the anaesthetist to the recovery nurse, covering the patient, the operation, the anaesthetic, problems met, fluids and blood loss, and the plan for pain, nausea and oxygen. The patient then has continuous pulse oximetry and frequent checks of airway, breathing rate, heart rate, blood pressure, consciousness, temperature, pain, nausea and the wound, with an anaesthetist available at once. Phase I recovery lasts until vital functions are stable and protective reflexes have returned; phase II, for day-case patients, prepares the patient to go home. Discharge follows written criteria rather than a fixed time: scoring systems such as the modified Aldrete score (for leaving phase I) and the post-anaesthesia discharge scoring system (for going home) check activity, breathing, circulation, consciousness, oxygen saturation, pain, nausea and bleeding.

## Key points

- Phase I recovery covers the immediate period until vital signs are stable and airway reflexes have returned; phase II prepares day-case patients for home.
- Supplemental oxygen is given to most patients on arrival because hypoventilation and atelectasis are common after general anaesthesia.
- Sedation is checked together with breathing: opioid-induced respiratory depression is usually preceded by rising sleepiness.
- Pain and nausea are scored regularly with a simple scale and treated before discharge, because both delay recovery and prolong the stay.
- Voiding before discharge is required mainly when the risk of urinary retention is high, for example after spinal anaesthesia, pelvic or hernia surgery, or a previous retention.

## Components

- A bed space with oxygen, suction, a self-inflating bag and continuous monitoring (pulse oximetry, ECG, non-invasive blood pressure, capnography when needed).
- Airway equipment and emergency drugs at hand, including reversal agents for opioids and for muscle relaxants.
- Trained recovery nurses, usually one to one until the patient is awake and maintaining the airway.
- An anaesthetist responsible for the unit and immediately available, and a written policy with discharge criteria.

## How it works

- Anaesthetic agents wear off as they redistribute and are eliminated; until then they blunt the ventilatory response to carbon dioxide and to low oxygen.
- Upper airway muscles lose tone in the drowsy patient, so the tongue and soft tissues can obstruct the airway, especially in obstructive sleep apnoea or obesity.
- Hypotension in recovery comes mainly from hypovolaemia (bleeding, too little fluid), vasodilation (neuraxial block, drugs) or, less often, the heart.
- Hypertension and tachycardia are often due to pain, a full bladder, hypercapnia or hypoxaemia, which must be ruled out before treating the number.

## Step by step

- Receive a structured handover at the bedside — information lost at handover is a common cause of avoidable harm.
- Check airway, breathing and oxygen saturation first — obstruction and hypoxaemia are the commonest early dangers.
- Record heart rate, blood pressure, temperature and consciousness, and repeat them at set intervals — trends show deterioration earlier than single values.
- Score pain, nausea and sedation, and treat by the agreed plan — untreated pain and nausea delay discharge and cause harm.
- Check the wound, drains, urine output and limb sensation after a block — surgical and block complications show here first.
- Apply the discharge score and written criteria before transfer — a fixed time in recovery does not guarantee safety.
- Hand over to the ward or to the escort with written instructions — the next team must know the plan for pain, nausea and warning signs.

## Modified Aldrete score (each item 0 to 2)

| Item | 2 points | 1 point | 0 points |
| --- | --- | --- | --- |
| Activity | Moves all four limbs on command | Moves two limbs | Moves no limbs |
| Respiration | Breathes deeply and coughs freely | Short or limited breathing | Apnoeic |
| Circulation | Blood pressure within 20% of the pre-anaesthetic value | Within 20% to 50% | More than 50% away |
| Consciousness | Fully awake | Rousable on calling | Not responding |
| Oxygen saturation | Above 92% on room air | Needs oxygen to stay above 90% | Below 90% even with oxygen |

## In practice

- Snoring, paradoxical chest movement or falling saturation: open the airway with jaw thrust or an airway adjunct, give oxygen and look for the cause.
- Persistent weakness or a floppy, shallow-breathing patient after muscle relaxants suggests residual block: check with a nerve stimulator and reverse.
- Excessive sleepiness with slow breathing after opioids: stimulate, support breathing and give an opioid antagonist if needed, then watch for re-sedation.
- Emergence agitation, especially in children and the elderly: rule out hypoxaemia, pain and a full bladder before giving sedatives.
- Bleeding, a tense wound or rising drain output with tachycardia: tell the surgeon early.

## Next step

- If the airway obstructs or saturation falls despite simple manoeuvres, call the anaesthetist at once.
- Do not move a patient on until the discharge score and the written criteria are met; record the score.
- Day-case patients go home only with a responsible adult, written instructions and a number to call.
- Report unexpected events (reintubation, unplanned admission, prolonged block) to the anaesthetist and record them for audit.
- Ward staff should continue regular checks of breathing, sedation, pain and nausea, with clear triggers for calling a doctor.

## Test yourself

Think of the answer, then tap the question to see it.

## What are the five items of the modified Aldrete score?

Activity, respiration, circulation, consciousness and oxygen saturation, each scored 0 to 2; 9 or more usually allows leaving phase I recovery.

## Why is rising sleepiness important in a patient receiving opioids in recovery?

Sedation usually comes before opioid-induced respiratory depression, so increasing drowsiness is an early warning to reduce opioids and support breathing.

## What should be ruled out before treating hypertension and tachycardia in recovery?

Pain, a full bladder, hypoxaemia and hypercapnia, which commonly cause them and need their own treatment.

## How does residual neuromuscular blockade show itself after surgery?

Weakness, a weak cough, shallow breathing, airway obstruction and risk of aspiration; it is confirmed with a nerve stimulator and treated with reversal.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/the-recovery-unit-monitoring-and-discharge-criteria/)

## Elsewhere in DurgiPedia

- [Immediate recovery after anaesthesia: monitoring and discharge criteria](https://durgical.com/en/nursing/immediate-recovery-after-anaesthesia-monitoring-and-discharge-criteria/)
- [Postoperative care on the ward: the first 24–48 hours](https://durgical.com/en/nursing/postoperative-care-on-the-ward-the-first-24-48-hours/)
- [Recognising deterioration and calling the rapid response team](https://durgical.com/en/nursing/recognising-deterioration-and-calling-the-rapid-response-team/)
- [Vital signs: what they are and how to record them](https://durgical.com/en/clinical-exam/vital-signs-what-they-are-and-how-to-record-them/)
- [The causes of hypoxemia](https://durgical.com/en/physiology/the-causes-of-hypoxemia/)

## Connections

## Related 8

- [Postoperative nausea and vomiting](https://durgical.com/en/anaesthesia/postoperative-nausea-and-vomiting/)
- [Postoperative pain: multimodal analgesia](https://durgical.com/en/anaesthesia/postoperative-pain-multimodal-analgesia/)
- [Postoperative delirium](https://durgical.com/en/anaesthesia/postoperative-delirium/)
- [Perioperative hypothermia and shivering](https://durgical.com/en/anaesthesia/perioperative-hypothermia-and-shivering/)
- [Postoperative oliguria and fluids](https://durgical.com/en/anaesthesia/postoperative-oliguria-and-fluids/)
- [Extubation: when and how](https://durgical.com/en/anaesthesia/extubation-when-and-how/)
- [Standard intraoperative monitoring](https://durgical.com/en/anaesthesia/standard-intraoperative-monitoring/)
- [Bronchospasm and laryngospasm](https://durgical.com/en/anaesthesia/bronchospasm-and-laryngospasm/)

## Related conditions 4

- [Atelectasis](https://durgical.com/en/conditions/atelectasis/)
- [Opioid overdose](https://durgical.com/en/conditions/opioid-overdose/)
- [Acute urinary retention](https://durgical.com/en/conditions/acute-urinary-retention/)
- [Obstructive sleep apnoea](https://durgical.com/en/conditions/obstructive-sleep-apnoea/)

## In Pharmacology 6

- [Naloxone](https://durgical.com/en/pharmacology/naloxone/)
- [Neuromuscular block reversal agents](https://durgical.com/en/pharmacology/classes/neuromuscular-block-reversal-agents/)
- [Sugammadex](https://durgical.com/en/pharmacology/sugammadex/)
- [Neostigmine](https://durgical.com/en/pharmacology/neostigmine/)
- [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)
- [5-HT3 receptor antagonists (setrons)](https://durgical.com/en/pharmacology/classes/5-ht3-receptor-antagonists/)

[← All of anaesthesia](https://durgical.com/en/anaesthesia/)

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Postoperative Pain Control](https://www.ncbi.nlm.nih.gov/books/NBK544298/) (StatPearls (NCBI Bookshelf), 2024); [Postoperative Nausea](https://www.ncbi.nlm.nih.gov/books/NBK500029/) (StatPearls (NCBI Bookshelf), 2022).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anaesthesia/the-recovery-unit-monitoring-and-discharge-criteria/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/the-recovery-unit-monitoring-and-discharge-criteria/