Richmond Agitation-Sedation Scale (RASS)
Depth of sedation and agitation in ICU patients
Sources last checked: 2026-10-13
Richmond Agitation-Sedation Scale (RASS)
Depth of sedation and agitation in ICU patients
Assess in steps: observe for 30 s; if not alert, say the name and ask the patient to open the eyes and look at you; only if there is no response to voice, use physical stimulation (shake shoulder, then sternal rub).
Interpretation
| −5 to −4 — deep sedation / unarousable | Deep sedation or unarousable; delirium screening is not possible at this level. |
|---|---|
| −3 to −1 — moderate to light sedation | Moderate to light sedation. Light sedation (around 0 to −2) is the usual target unless deep sedation is indicated. |
| 0 — alert and calm | |
| +1 to +2 — restless or agitated | Restless or agitated. Common causes include pain, delirium, hypoxaemia, withdrawal and urinary retention. |
| +3 to +4 — very agitated or combative | Very agitated or combative; by the RASS definitions this level includes pulling or removing tubes and catheters and immediate danger to staff. |
What is the Richmond Agitation-Sedation Scale (RASS)?
The Richmond Agitation-Sedation Scale (RASS) is a 10-level scale from +4 (combative) to −5 (unarousable), with 0 meaning alert and calm. Sessler and colleagues developed and validated it in adult ICU patients in Richmond, Virginia, in 2002, and Ely and colleagues confirmed its reliability over time. It is widely used in ICUs and is the entry step for CAM-ICU delirium screening.
When to use it
- Routine sedation assessment in ventilated and non-ventilated ICU patients, typically every few hours
- Titrating sedatives to a prescribed target level
- Before delirium screening, which requires RASS −3 or higher
When not to use it
- Patients receiving neuromuscular blockers — motor responses cannot be assessed
- As a measure of pain — use a dedicated pain scale
How it is calculated
| Criterion | Points |
|---|---|
| Observed level | |
| +4 Combative — overtly combative or violent; immediate danger to staff | 4 |
| +3 Very agitated — pulls or removes tubes or catheters; aggressive | 3 |
| +2 Agitated — frequent non-purposeful movement, fights the ventilator | 2 |
| +1 Restless — anxious, but movements not aggressive or vigorous | 1 |
| 0 Alert and calm | 0 |
| −1 Drowsy — not fully alert, sustained (> 10 s) eye opening and eye contact to voice | -1 |
| −2 Light sedation — briefly (< 10 s) awakens with eye contact to voice | -2 |
| −3 Moderate sedation — movement or eye opening to voice, but no eye contact | -3 |
| −4 Deep sedation — no response to voice, movement or eye opening to physical stimulation | -4 |
| −5 Unarousable — no response to voice or physical stimulation | -5 |
Clinical pearls and limitations
- Assess in steps: observe for 30 s; if not alert, say the name and ask the patient to open the eyes and look at you; only if there is no response to voice, use physical stimulation (shake shoulder, then sternal rub).
- Follow the steps: observation first, then voice, then physical stimulation — the step at which the patient responds defines the level.
- The difference between −1 and −2 is whether eye contact to voice lasts more or less than 10 seconds.
- Light sedation is the usual target unless there is a specific indication for deep sedation (e.g. refractory hypoxaemia, raised intracranial pressure).
- Record the target RASS alongside the actual RASS so the whole team titrates to the same goal.
Frequently asked questions
What is a normal RASS score?
0 — alert and calm. Positive scores indicate agitation and negative scores sedation.
What RASS is deep sedation?
−4 (no response to voice, but movement to physical stimulation) and −5 (unarousable).
What RASS is needed for CAM-ICU?
Delirium can only be screened at RASS −3 or above; at −4 or −5 the patient is reassessed later.
How long does a RASS assessment take?
Usually under a minute: about 30 seconds of observation, followed by verbal and, if needed, physical stimulation.
Evidence and guidelines
- Primary source: Sessler CN, Gosnell MS, Grap MJ, et al. The Richmond Agitation-Sedation Scale: validity and reliability in adult intensive care unit patients. Am J Respir Crit Care Med 2002;166(10):1338-1344.
- Ely EW, Truman B, Shintani A, et al. Monitoring sedation status over time in ICU patients: reliability and validity of the Richmond Agitation-Sedation Scale (RASS). JAMA 2003;289(22):2983-2991.
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