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Richmond Agitation Sedation Scale (RASS)

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The Richmond Agitation Sedation Scale (RASS) is an instrument designed to assess the level of alertness and agitated behavior in critically-ill patients.

Richmond Agitation Sedation Scale (RASS)


The scale was developed by a team of critical care physicians, nurses, and pharmacists with the aim of achieving the following:

  1. Establish simple and discrete criteria for assessing arousal and agitation;
  2. Guide sedation therapy to better meet patients’ titration needs; and
  3. Improve communication regarding sedation and agitation among healthcare providers.


The RASS is a 10-point scale ranging from -5 to +4. Levels -1 to -5 denote 5 levels of sedation, starting with “awakens to voice” and ending with “unarousable.” Levels +1 to +4 describe increasing levels of agitation. The lowest level of agitation starts with apprehension and anxiety, and peaks at combative and violent. RASS level 0 is “alert and calm.” The full scale can be found below:

Richmond Agitation and Sedation Scale


The RASS is mostly applied in mechanically-ventilated patients, but may be used for any individual who is hospitalized. Regular administration and assessment is particularly useful for patients who are critically-ill, are receiving sedative medications, and/or demonstrate fluctuating levels of consciousness.


The RASS can be administered in a little as 30-60 seconds. Scoring is based on observation, and response to auditory and physical stimulation. Sessler et al. describe the testing procedure as follows:

Scoring and Interpretation

RASS scoring and interpretation should be based on the sedation protocol being used. For minimal sedation protocols (RASS -2 to 0), sedation should be modified or decreased for a RASS score of -3 or less. Scores of 2 to 4 may indicate under-sedation. At minimum, the patient should be assessed for pain, delirium, and anxiety. In addition, other underlying causes of agitation should be investigated and treated as appropriate.

In select cases, a deep sedation protocol (RASS -4 and -5) may be used. For scores of -3 or higher, sedation should be modified to achieve the desired range.

Psychometric information

The RASS demonstrates strong validity and reliability across a range of critical care populations. Inter-rater reliability has been found to be good to excellent in adult ICU patients on surgical, medical, coronary, cardiac surgery, and neuroscience ICUs. This includes patients with and without mechanical ventilation and sedative medications. Although most studies were conducted in the United States, inter-rater reliability remained high in Swedish and Portuguese ICU settings as well.

In adult ICU patients in the U.S., the RASS demonstrates good criterion, construct, and face validity. Kerson et al. also found high criterion validity in critically-ill children.


The RASS has many advantages compared to other sedation-agitation scales. Aside from strong inter-rater reliability and ease of administration, use of the RASS improves discrimination between different levels of mild to moderate sedation (+1 to -4). Moreover, the scale is applicable to multiple disciplines, has been heavily studied, and is referenced as a key assessment tool for clinical guidelines related to pain, agitation, and delirium.


In patients with severe auditory and visual deficits, the RASS is not a suitable instrument for assessing arousal and agitation. Although the scale is well-researched in the U.S., studies assessing validity and reliability are limited in other geographical locations and languages other than English.

Physical Therapy Implications

For physical therapy clinicians, the RASS can be used to streamline communication regarding sedation and agitation with other healthcare providers. Resulting scores can guide decision making regarding the appropriateness of physical therapy intervention, and treatment priority. The RASS may also identify patients in need of further assessment and management for pain, agitation, and delirium.


The RASS is freely available online.

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