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RASS

Richmond Agitation-Sedation Scale for ICU sedation assessment

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Why use it

Standard sedation assessment tool in ICUs worldwide. Required before CAM-ICU delirium screening. Guides sedation titration to target levels. Simple, reliable, inter-rater agreement > 0.9.

About

The Richmond Agitation-Sedation Scale (RASS) is a 10-point scale used to assess the level of sedation and agitation in ICU patients. It ranges from -5 (unarousable) to +4 (combative), with 0 being alert and calm. RASS is used to titrate sedation to target levels and is a prerequisite for delirium assessment with CAM-ICU.

When to use

  • ICU sedation monitoring (every 2-4 hours, or with medication changes)
  • Before CAM-ICU delirium assessment (requires RASS ≥ -3)
  • Sedation titration for mechanically ventilated patients
  • Assessment of agitation level for safety interventions

Formula

Assessment steps: 1. Observe patient (30 seconds) 2. If not alert: call name, ask to open eyes/make eye contact 3. If no response to voice: physically stimulate (shoulder shake) Score from +4 (combative) to -5 (unarousable)

Pearls & pitfalls

  • Lighter sedation targets (RASS 0 to -2) are associated with shorter ICU stays and fewer ventilator days.
  • CAM-ICU can only be performed if RASS ≥ -3 (anything deeper = assessment not possible).
  • RASS +1 to +4: First assess for REVERSIBLE causes (pain, full bladder, ETT displacement, hypoxia).
  • Daily sedation interruption (awakening trial) is recommended for most mechanically ventilated patients.
  • RASS has excellent inter-rater reliability (κ = 0.91-0.94).
  • Document RASS with every nursing assessment and sedation dose change.

Next steps

Target RASS 0 to -2 for most ICU patients (light sedation strategy). RASS +1 to +4: Assess for pain, delirium, hypoxia before increasing sedation. RASS -4 to -5: Hold sedation, daily awakening trial. Perform CAM-ICU when RASS ≥ -3.

Evidence

Developed and validated by Sessler et al. (Am J Respir Crit Care Med, 2002). Inter-rater reliability κ > 0.9. Adopted worldwide as primary ICU sedation tool. PAD guidelines (SCCM 2018) recommend light sedation (RASS 0 to -2) for most patients.

References

  1. Sessler CN et al. The Richmond Agitation-Sedation Scale. Am J Respir Crit Care Med. 2002;166(10):1338-1344. — link
  2. Devlin JW et al. Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU. Crit Care Med. 2018;46(9):e825-e873. — link