RASS Scale Calculator

RASS Scale Calculator for Critical Care. A RASS of 0 is a calm, alert patient. Positive scores flag agitation needing evaluation for pain, delirium, hypoxia, or under-sedation, with +3/+4 demanding immediate safety intervention. Scores of -1 to -2 represent the light-sedation target endorsed by current guidelines and associated with shorter ventilation and ICU stay. Scores of -3 to -5 indicate progressively deeper sedation; -4 and -5 mean the patient responds only to physical stimulation or not at all, cannot be delirium-screened, and generally warrant reducing sedatives unless deep sedation is clinically mandated (e.g., refractory intracranial hypertension, severe ARDS, neuromuscular blockade).

How this calculator works

The Richmond Agitation-Sedation Scale is a single-observation ordinal scale that grades a patient's arousal and agitation across ten discrete levels, from +4 (overtly combative, danger to staff) through 0 (alert and calm) down to -5 (unarousable, no response to voice or physical stimulation). Scoring follows a fixed stepwise procedure: first observe the patient, then use graded voice, then physical stimulation, and classify the response by whether eye opening and eye contact are sustained and for how long. The positive scores (+1 to +4) capture escalating agitation; the negative scores split into light sedation (-1 to -3, some response to voice) and deep sedation or coma (-4 to -5, response only to physical stimulation or none).

When to use this calculator

Use RASS at the bedside in mechanically ventilated and non-ventilated adult ICU patients to set and titrate a sedation target, most often a light-sedation goal of 0 to -2, and to trigger daily sedation interruption. It is the arousal gateway for the CAM-ICU delirium assessment: a patient must be at RASS -3 or above to be assessable. It should not be used to grade coma etiology or as a substitute for the Glasgow Coma Scale in primary neurologic injury, nor is it validated for procedural sedation outside critical care or for pediatric patients.

Inputs used

  • Observation of agitation
  • Response to voice
  • Response to physical stimulation

Clinical interpretation

A RASS of 0 is a calm, alert patient. Positive scores flag agitation needing evaluation for pain, delirium, hypoxia, or under-sedation, with +3/+4 demanding immediate safety intervention. Scores of -1 to -2 represent the light-sedation target endorsed by current guidelines and associated with shorter ventilation and ICU stay. Scores of -3 to -5 indicate progressively deeper sedation; -4 and -5 mean the patient responds only to physical stimulation or not at all, cannot be delirium-screened, and generally warrant reducing sedatives unless deep sedation is clinically mandated (e.g., refractory intracranial hypertension, severe ARDS, neuromuscular blockade).

Worked example

A ventilated post-operative patient opens the eyes and makes brief eye contact for under 10 seconds when addressed by name, then drifts off. Sustained-to-voice would be -2; because eye contact is present but not sustained, this is RASS -3 (moderate sedation). If the target is 0 to -2, the score of -3 signals slightly deeper sedation than intended, prompting a downward adjustment of the infusion; note the patient at -3 is still above the -4 cutoff, so a CAM-ICU delirium screen can proceed.

Limitations and safety notes

RASS measures arousal, not the cause of altered mental status: a low score from oversedation looks identical to one from an evolving stroke, seizure, or metabolic coma, so a new or unexplained drop demands neurologic workup rather than a sedation adjustment alone. It is unreliable in patients with fixed sensory deficits (deafness), receiving neuromuscular blockade, or with baseline cognitive impairment or dementia, and it was validated in adults only. Because scoring depends on the response to escalating stimulation, inconsistent technique between assessors degrades reproducibility despite otherwise high inter-rater agreement.

Frequently asked questions

What RASS score should I target for most ICU patients?

For most mechanically ventilated adults, a light-sedation target of 0 to -2 is recommended and is linked to shorter ventilation and ICU length of stay. Deeper sedation (-3 to -5) is reserved for specific indications such as raised intracranial pressure, severe ARDS, or during neuromuscular blockade.

How does RASS relate to the CAM-ICU delirium assessment?

RASS is the arousal prerequisite for CAM-ICU. A patient must score -3 or higher (that is, respond to voice) to be assessable. At RASS -4 or -5 the patient responds only to physical stimulation or not at all, so delirium screening is deferred and rechecked when arousal improves.

How is RASS different from the Glasgow Coma Scale?

RASS is a purpose-built sedation and agitation scale that spans agitation (positive scores) as well as sedation, and in validation studies showed superior inter-rater reliability to the GCS for tracking sedation over time. The GCS was designed to grade depth of coma in neurologic injury and does not capture agitation.

How do I actually assign a score at the bedside?

Observe first: if the patient is alert and calm, score 0; agitated behaviors score positive. If not fully alert, call the name and judge how long eye contact is sustained (sustained over ~10 seconds is -1, briefer is -2, movement or eye opening without contact is -3). If there is no response to voice, apply physical stimulation: movement to touch is -4, no response at all is -5.

Can RASS tell me why a patient is oversedated or comatose?

No. RASS quantifies the depth of arousal but not its cause. An unexpectedly low score could reflect drug accumulation, hepatic or renal impairment, or a new neurologic event, so a new or unexplained decline should prompt a workup rather than assuming it is medication effect.

References

  • 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. PMID: 12421743.
  • 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. PMID: 12799407.
  • Devlin JW, Skrobik Y, Gelinas C, 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. PMID: 30113379.

Editorial review and citation methodology

Reviewed by the Quick Medical Calculator Editorial Team. Last reviewed: June 25, 2026. The review checks calculator inputs, intended population, interpretation, limitations, and source alignment.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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