What is the Standard Sedation Scale?

October 13, 2025 •

4 min read

In adult intensive care units, over one-third of mechanically ventilated patients may experience over-sedation during the first 48 hours, demonstrating a critical need for accurate assessment tools. A standardized sedation scale, most prominently the Richmond Agitation-Sedation Scale (RASS), is the fundamental tool healthcare providers use to objectively evaluate a patient's level of consciousness and agitation.

Quick Summary

Standard sedation scales, particularly the validated RASS and SAS, provide a consistent method for evaluating a patient's consciousness level. This assessment guides precise medication adjustments, helps maintain targeted sedation goals, and improves patient outcomes in critical care settings.

Key Points

Richmond Agitation-Sedation Scale (RASS): The most widely used and validated tool for assessing adult sedation and agitation, especially in the ICU.
Riker Sedation-Agitation Scale (SAS): Another reliable 7-point scale, often used interchangeably with RASS, for assessing agitation and sedation levels.
Clinical Procedure: RASS assessment follows a standardized 3-step process: observe the patient, stimulate with voice, and stimulate with touch, if necessary.
Importance of Objective Assessment: Standardized scales reduce subjective interpretation, leading to safer, more precise medication titration and better patient outcomes.
Light Sedation Targets: Using validated scales to maintain light sedation has been shown to reduce a patient's time on mechanical ventilation and hospital stay.
Pediatric Assessment: Specialized scales, like the COMFORT-B scale, are used for assessing pain and sedation in pediatric patients.
Delirium Management: Proper sedation assessment is the crucial first step before evaluating for delirium with other tools like the CAM-ICU.

The Dominant Standard: Richmond Agitation-Sedation Scale (RASS)

In modern critical care, the Richmond Agitation-Sedation Scale (RASS) is widely regarded as the standard assessment tool for measuring a patient's level of sedation and agitation. Developed by a multidisciplinary team at Virginia Commonwealth University, RASS provides a reliable and reproducible method for evaluating patient status with a high degree of inter-rater reliability. Its ease of use and quick administration, often taking less than a minute, have made it the preferred scale in many clinical settings.

How to Perform a RASS Assessment

The RASS assessment is performed in three simple, sequential steps to determine a patient's score on a 10-point scale ranging from +4 (combative) to -5 (unarousable).

Observation: The healthcare provider first observes the patient. Is the patient alert and calm? If so, the score is 0. If the patient appears restless or agitated, a score from +1 to +4 is assigned based on their behavior.
Verbal Stimulation: If the patient is not alert, the provider speaks their name in a loud voice and instructs them to open their eyes. The response determines if the patient is drowsy (-1), lightly sedated (-2), or moderately sedated (-3) based on the duration of eye contact.
Physical Stimulation: If there is no response to verbal commands, the provider physically stimulates the patient by gently shaking their shoulder or rubbing their sternum. Any movement in response results in a -4 (deep sedation), while no response at all indicates a -5 (unarousable).

The Clinical Importance of Using Standardized Scales

The use of validated sedation scales is critical for ensuring patient safety and optimizing care in the intensive care unit (ICU). Standardized assessment provides a clear, objective metric that informs several aspects of patient management.

Guiding Medication Titration

With a precise score, clinicians can effectively titrate sedative and analgesic medications to achieve a specific target level of sedation. This prevents both under-sedation, which can lead to patient distress, anxiety, and self-harm, and over-sedation, which can cause prolonged mechanical ventilation and extended hospital stays. Research has shown that targeting light sedation with scales like RASS can reduce a patient's time on a ventilator and shorten their overall ICU and hospital length of stay.

Interplay with Delirium Assessment

Accurate sedation scoring is a prerequisite for reliable delirium screening. A patient's level of consciousness must first be established before they can be assessed for delirium using tools like the Confusion Assessment Method for the ICU (CAM-ICU). The RASS helps confirm a patient is adequately arousable for a valid delirium test, distinguishing a decreased consciousness from an active delirium state.

Comparison of Common Sedation Scales

While RASS is often considered the gold standard, other scales are also used in clinical practice, each with distinct features. The Riker Sedation-Agitation Scale (SAS) is another well-validated and reliable tool, particularly in critical care. An older but still referenced scale is the Ramsay Sedation Scale (RSS).


Feature	Richmond Agitation-Sedation Scale (RASS)	Riker Sedation-Agitation Scale (SAS)	Ramsay Sedation Scale (RSS)
Score Range	10 points (+4 to -5)	7 points (1 to 7)	6 points (1 to 6)
Agitation Levels	4 levels (+1 to +4)	3 levels (5 to 7)	1 level (agitated/restless)
Sedation Levels	5 levels (-1 to -5)	3 levels (1 to 3)	3 levels (4 to 6)
Key Distinction	Uses eye contact duration as key metric for verbal stimulation response	Separates agitation levels with specific behavioral descriptions	Less discriminating between different levels of sedation
Validation	Extensive validation in adult ICU populations	Well-validated in critical care settings	Less validated than RASS and SAS
Primary Use	Adult critical care, research	Adult critical care	Older scale, less common today

Pediatric Sedation Assessment

For pediatric patients, specific assessment tools are used to account for developmental differences. The COMFORT Behavior Scale (COMFORT-B) is one such instrument, validated for use in pediatric intensive care units (PICUs). It evaluates a child's pain and distress based on several behavioral indicators, including alertness, calmness, movement, and muscle tone, without relying on physiological variables that can be influenced by medications. The RASS has also been validated for use in critically ill children, offering an alternative for assessing agitation and sedation levels.

The Role of Technology and Future Directions

Despite the reliability of subjective scales like RASS, research continues to explore objective measures of sedation, including processed electroencephalography (EEG) and bispectral index (BIS) monitoring. While promising for certain applications, these objective methods have not yet replaced subjective scales as the standard for routine sedation management due to variability and a lack of widespread validation in general critical care populations. Ultimately, the goal is to continuously refine assessment tools to provide the most personalized and safe care possible for sedated patients. The Society of Critical Care Medicine (SCCM) advocates for the use of validated scales like RASS and SAS as part of a comprehensive, goal-directed strategy for pain, sedation, and delirium management. For more information, refer to the ICU Delirium website.

Conclusion

In summary, knowing what is the standard sedation scale and how to use it is a cornerstone of best practice in modern critical care pharmacology. The Richmond Agitation-Sedation Scale (RASS) is the most widely validated and recommended tool for adults, providing a simple yet robust method for assessing a patient's state. It, along with other specialized scales like SAS for adults and COMFORT-B for pediatrics, enables healthcare teams to effectively manage patient comfort, titrate medications precisely, and improve clinical outcomes. By consistently and accurately assessing sedation and agitation, providers can prevent the complications of over- or under-sedation, ensuring a safer and more effective treatment journey for patients in their most vulnerable state.

Frequently Asked Questions

The RASS score is determined in three steps: observe the patient's behavior, use verbal stimulation by calling their name, and if needed, use physical stimulation by shaking their shoulder or rubbing their sternum.

RASS is a 10-point scale, while SAS is a 7-point scale. Both are well-validated for use in the ICU, but RASS offers more granular scoring for both agitation and sedation levels, particularly differentiating responses to verbal and physical stimuli.

Light sedation is often preferred because it is associated with better outcomes, including reduced duration of mechanical ventilation, shorter ICU and hospital stays, and fewer negative psychological effects like disturbing memories.

Yes. Pediatric patients have specialized tools like the COMFORT Behavior Scale (COMFORT-B), which is used in PICUs to assess pain and distress. The RASS has also been validated for use in critically ill children.

Sedation goals are determined by a patient's specific clinical needs, often aiming for light sedation (e.g., RASS 0 to -2) unless contraindicated. A multidisciplinary team sets these goals and adjusts medication based on ongoing scale assessments.

Sedation scales are used to assess the patient's level of arousal, which is the necessary first step before screening for delirium with specific tools like the CAM-ICU. A patient must be responsive enough for an accurate delirium assessment to be performed.

If a patient shows no response to verbal or physical stimulation, they receive a RASS score of -5, indicating an unarousable state.