Nursing care
RASS scale: how to score sedation and agitation, and when POSS is the better tool
Written and reviewed by Nicole Ramirez, BSN, RN, CMSRN · 4 min read · Updated November 2026
Short answer
The RASS scale scores a patient from +4 (combative) through 0 (alert and calm) to -5 (unarousable). Negative scores depend on how the patient responds to voice and then to touch. A RASS of -2 means the patient wakes to voice with eye contact for less than 10 seconds. Many ICUs target -1 to +1 unless deeper sedation is ordered.
The RASS levels in plain words
RASS has ten levels. Positive numbers describe agitation, zero is the calm baseline, and negative numbers describe how hard the patient is to wake. The descriptions below are summarized in our own words from the published scale.
| Score | Label | What you see |
|---|---|---|
| +4 | Combative | Violent, an immediate danger to staff |
| +3 | Very agitated | Pulls at or removes tubes, or is aggressive |
| +2 | Agitated | Frequent purposeless movement or fighting the ventilator |
| +1 | Restless | Anxious, but movements are not aggressive |
| 0 | Alert and calm | Pays attention to the caregiver without prompting |
| -1 | Drowsy | Wakes to voice with eye contact lasting more than 10 seconds |
| -2 | Light sedation | Wakes to voice with eye contact lasting less than 10 seconds |
| -3 | Moderate sedation | Moves or opens eyes to voice but makes no eye contact |
| -4 | Deep sedation | No response to voice; moves or opens eyes to physical touch |
| -5 | Unarousable | No response to voice or touch |
How to score: observe, then voice, then touch
Start by watching the patient without speaking. If they are alert, restless or agitated, score 0 to +4 from what you see. If not, say their name and ask them to open their eyes and look at you. Only if there is no response do you shake the shoulder, moving to a firmer stimulus if needed.
Worked example
- Observe: eyes closed, still, not fighting the ventilator, so not 0 or positive
- Voice: you call his name and ask him to look at you
- He opens his eyes and looks at you, then drifts off after about 5 seconds
- Eye contact to voice lasting under 10 seconds matches -2
- Compare with the ordered target, for example -1 to 0
Recent ICU literature defines deep sedation as RASS -2 or below and links it with delirium, prolonged immobility, delayed extubation and death, which is why a -2 against a -1 to 0 target matters.
Where the RASS misleads
The scale is only as good as the stimulus. In a 2025 study comparing bedside nurses with trained investigators, nurses recorded a lighter sedation level in about half of observations, and at least one assessor noted ambiguity in 16% of assessments. The fix is to perform the stimulus every time, calling the patient's name in the moment, rather than charting a general impression of the shift.
RASS measures arousal, not comfort or confusion. A patient at 0 can still be delirious, so ICUs pair it with a separate delirium screen rather than reading a calm score as a clear mind. It also says nothing about pain, so an agitated +2 may need analgesia rather than more sedative.
POSS: the ward tool for opioid sedation
Outside the ICU, the Pasero Opioid-Induced Sedation Scale (POSS) is used to catch rising sedation before respiratory depression. A POSS of 2, slightly drowsy and easily roused, is generally acceptable. One published postoperative protocol has nurses notify the team when POSS reaches 3 or more or respiratory rate drops below 10 breaths per minute.
The exam logic is to treat increasing sedation as the early warning sign that comes before a falling respiratory rate. If a postoperative client becomes hard to keep awake mid-conversation, the safe action is to hold the next opioid dose, stay with the client, check breathing and SpO2, and notify the prescriber, not to wait for the next scheduled check.
Sources and further reading
Relationship Between Patient State Index and Richmond Agitation Sedation Scale (Turkish Journal of Anaesthesiology and Reanimation, 2026), Table 1. RASS levels +4 to -5 with labels and descriptions, including the 10-second eye contact distinction between -1 and -2.
Inter-rater Agreement of Richmond Agitation Sedation Scale Assessments in Adult Patients Receiving Mechanical Ventilation (Critical Care Explorations, 2025). Observe, voice, then physical stimulation procedure; deep sedation defined as RASS -2 or below and its harms; target RASS -1 to +1 in the study ICUs; nurses recording lighter scores in 52% and ambiguity in 16%.
Implementing Evidence-Based, Phase-Specific Multimodal Analgesia for Total Joint Arthroplasty (Journal of Nursing Management, 2026). POSS used for nursing sedation monitoring with opioids; notify team if POSS is 3 or more or respiratory rate below 10.
Rapid intravenous symptom-inhibiting fentanyl induction protocol (Addiction Science and Clinical Practice, 2025). POSS score of 2 described as slightly drowsy, easily roused.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our med-surg practice questions are the closest set to what this page covers.
One question from the med-surg set
A client with chronic obstructive pulmonary disease has an oxygen saturation of 88% on 2 L/min via nasal cannula and is alert with no distress. What should the nurse do first?
Rationale
In COPD a saturation of 88–92% is the therapeutic target, not an emergency, and this client is alert with no distress. The first action is the independent nursing intervention that is least invasive and most likely to help: sit them up and reassess. Turning the oxygen up to 6 L/min risks blunting the hypoxic drive, and calling rapid response or drawing an ABG escalates ahead of an assessment you have not finished.
Answer: B
Common questions
What is a RASS score of -2?
Light sedation: the patient wakes when you speak and makes eye contact, but for less than 10 seconds. Recent ICU research groups -2 and below as deep sedation, which is linked with delirium and slower recovery.
What is the target RASS?
It is set by the prescriber for each patient. Many ICUs aim for light sedation, often -1 to +1, unless there is a specific reason for deeper sedation.
When should opioids be held on the POSS scale?
A POSS of 2 is generally acceptable. At 3 or more, or a respiratory rate below 10, the safe response is to hold further opioid, stay with the client, assess breathing and notify the prescriber under local protocol.
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