Patients on ventilators and in intensive care often need sedation for comfort and safety. But too much sedation prolongs ventilation, increases delirium and slows recovery; too little causes distress and risks dislodging tubes and lines. International guidelines (such as the Society of Critical Care Medicine’s PADIS guideline) recommend light sedation for most patients, assessed regularly with a validated tool. The most widely used is the Richmond Agitation-Sedation Scale (RASS).
The RASS
| Score | Term | Description |
|---|---|---|
| +4 | Combative | Overtly combative, violent, danger to staff |
| +3 | Very agitated | Pulls or removes tubes or catheters; aggressive |
| +2 | Agitated | Frequent non-purposeful movement, fights ventilator |
| +1 | Restless | Anxious but movements not aggressive |
| 0 | Alert and calm | |
| −1 | Drowsy | Not fully alert, but sustained awakening (eyes open, eye contact) to voice for 10 seconds or more |
| −2 | Light sedation | Briefly awakens with eye contact to voice (under 10 seconds) |
| −3 | Moderate sedation | Movement or eye opening to voice, but no eye contact |
| −4 | Deep sedation | No response to voice, but movement or eye opening to physical stimulation |
| −5 | Unrousable | No response to voice or physical stimulation |
How to assess
- Observe the patient. If alert, restless or agitated, score 0 to +4.
- If not alert, say the patient’s name and ask them to open their eyes and look at you. Score −1 to −3 based on the response.
- If no response to voice, physically stimulate (shake shoulder, then rub sternum if needed). Score −4 or −5.
A common target for most ventilated patients is RASS 0 to −2 (calm to lightly sedated), unless deeper sedation is clinically needed (e.g. severe respiratory failure, raised intracranial pressure, neuromuscular blockade). The target should be prescribed and reviewed daily.
Analgesia first
Agitation is often caused by pain. Assess pain with a tool such as the Critical-Care Pain Observation Tool (CPOT) or Behavioral Pain Scale (BPS), and treat pain before adding sedatives (“analgesia-first” sedation). See our pain assessment guide.
Daily sedation interruption and breathing trials
Many ICUs use daily spontaneous awakening trials (pausing or reducing sedation) paired with spontaneous breathing trials, which can shorten time on the ventilator. Nurses play a central role: checking safety criteria, monitoring the patient closely, and communicating with the team.
Screen for delirium
If the RASS is −3 or higher (i.e. the patient responds to voice), screen for delirium with the CAM-ICU or ICDSC at least once per shift. Delirium in ICU is common and linked to worse outcomes. See our delirium guide.
The ABCDEF bundle
- Assess, prevent and manage pain.
- Both spontaneous awakening and breathing trials.
- Choice of analgesia and sedation.
- Delirium: assess, prevent and manage.
- Early mobility and exercise.
- Family engagement and empowerment.
Implementing the bundle has been associated with better survival and less delirium in large studies.
Based on the Richmond Agitation-Sedation Scale (Sessler et al., 2002), the SCCM PADIS guideline (2018) and the ICU Liberation ABCDEF bundle. Educational content: follow your unit’s protocol.