What is the RASS scale?

The RASS (Richmond Agitation-Sedation Scale) is a 10-point scale that measures the level of sedation and agitation in ICU patients. It ranges from −5 (unarousable) to +4 (combative), with 0 representing an alert and calm state. It is the recommended sedation assessment tool by SCCM guidelines.

How do you assess RASS?

Step 1: Observe the patient. If alert and calm (or agitated), score 0 to +4. Step 2: If not alert, call the patient's name and ask them to open their eyes. Score −1 to −3 based on response. Step 3: If no response to verbal stimulation, physically stimulate (trapezius squeeze). Score −4 to −5 based on response.

What RASS target is recommended for ICU patients?

The SCCM PADIS guidelines recommend a target RASS of −2 to 0 (light sedation) for most ICU patients, as deep sedation (RASS −4 to −5) is associated with longer mechanical ventilation, delirium, and increased mortality. Exceptions include specific situations like neuromuscular blockade or refractory intracranial hypertension.

How does RASS relate to CAM-ICU?

RASS must be assessed before CAM-ICU. If RASS is −4 or −5 (deeply sedated/unarousable), the patient cannot be assessed for delirium. If RASS is −3 or higher, proceed with CAM-ICU assessment. This two-step approach (RASS → CAM-ICU) is part of the standard ICU sedation and delirium monitoring protocol.

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RASS — Richmond Agitation-Sedation Scale

Standardized sedation assessment for ICU patients. Score range: −5 (unarousable) to +4 (combative). Target is typically 0 to −2.

Select RASS Level

Observation

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Select a RASS level to see interpretation.

+4 to +1Agitated — consider causes (pain, delirium, anxiety)

0Alert and calm — ideal for most patients

−1 to −2Light sedation — typical ICU target

−3 to −5Deep sedation — evaluate for over-sedation

Disclaimer: For educational purposes only. Not a substitute for clinical judgment.

When to use

RASS is used in every ICU assessment to standardize sedation monitoring. It is the first step in the CAM-ICU delirium assessment (CAM-ICU requires RASS ≥ −3 to be evaluable).

Clinical pearls

Target RASS 0 to −2 for most mechanically ventilated patients (PADIS guidelines 2018).
RASS −3 to −5 is associated with increased mortality, longer ICU stay, and higher delirium rates.
Assess RASS before giving sedation — many "agitated" patients have undertreated pain.
Daily sedation interruption and spontaneous awakening trials (SAT) should target RASS 0 to −1.
RASS must be ≥ −3 to perform CAM-ICU delirium assessment.

How to Score

Observe patient for 30 seconds. If alert/restless/agitated → score +1 to +4.
If not alert, call patient's name and ask to open eyes/look at you. Score based on response duration.
If no response to voice, physically stimulate (shoulder shake/sternal rub). Score −4 or −5.

References

Sessler CN, et al. The Richmond Agitation-Sedation Scale: validity and reliability in adult ICU patients. Am J Respir Crit Care Med. 2002;166(10):1338-1344.
Devlin JW, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption (PADIS). Crit Care Med. 2018;46(9):e825-e873.

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About This Tool

What Is the RASS?

The Richmond Agitation-Sedation Scale (RASS) is a validated 10-point scale developed at Virginia Commonwealth University for measuring sedation level in ICU patients. Published by Sessler et al. in 2002, it ranges from −5 (unarousable) through 0 (alert and calm) to +4 (combative). RASS has become the most widely used sedation scale in critical care and is a core component of the ABCDEF ICU liberation bundle.

Why It Matters

Over-sedation (RASS −3 to −5) is independently associated with increased mortality, prolonged mechanical ventilation, and higher delirium rates. The 2018 PADIS guidelines recommend targeting light sedation (RASS 0 to −2) over deep sedation for most critically ill adults. RASS-targeted sedation protocols reduce sedative exposure and improve patient outcomes.

🔑 Clinical Pearls

RASS is step 1 of the ABCDEF bundle: Assess, both SAT & SBT, Choice of sedation, Delirium monitoring, Early mobility, Family engagement.
If RASS is −4 or −5, the patient cannot be assessed for delirium with CAM-ICU — document "unable to assess."
Agitation (RASS +1 to +4) should trigger a differential: pain, delirium, anxiety, ventilator dyssynchrony, full bladder, ETT malposition.
RASS has excellent inter-rater reliability (κ = 0.91) between nurses and physicians.

Key References

Sessler CN, et al. The Richmond Agitation-Sedation Scale. Am J Respir Crit Care Med. 2002;166(10):1338-1344.
Ely EW, et al. Monitoring sedation status over time in ICU patients: reliability and validity of the RASS. JAMA. 2003;289(22):2983-2991.

Formula last verified: February 2026