Richmond Agitation Sedation Scale Calculator

The RASS measures arousal on a single ordinal axis running from +4, overtly combative, through 0, alert and calm, to -5, unarousable. Its defining feature is not the labels but the assessment procedure, which is fixed in three steps and produces the score without judgment calls: observe for 30 seconds and score any spontaneous agitation; if the patient is not spontaneously alert, call their name and score by whether eye contact is sustained beyond 10 seconds (-1), brief (-2), or absent with some movement (-3); if voice produces nothing, apply a shoulder shake or trapezius squeeze, scoring -4 for movement and -5 for none. Because the boundary between -1 and -2 is a stopwatch rather than an impression, inter-rater agreement is high, with weighted kappa values around 0.91 to 0.94 in validation work. Current critical care guidance targets light sedation, RASS -2 to 0, for most ventilated patients, since randomized trials link lighter targets to shorter ventilation, shorter unit stay and less delirium. Deep targets of -4 to -5 remain appropriate for neuromuscular blockade, refractory intracranial hypertension, status epilepticus and severe respiratory failure requiring strict ventilator synchrony. Two caveats matter. A positive score is a symptom, not a diagnosis: untreated pain, hypoxia, urinary retention and withdrawal all present as agitation and are worsened by adding sedative. And the scale measures arousal only, so a patient at RASS 0 may still be delirious, which is why the RASS gates rather than replaces a CAM-ICU assessment.

Before the RASS, the reference sedation scale was the six-point instrument published by Michael Ramsay and colleagues in the British Medical Journal in 1974, developed while studying the steroid anesthetic alphaxalone-alphadolone. The Ramsay scale was widely adopted but criticized for conflating agitation with anxiety, offering no graded description of agitation, and depending on subjective wording that different assessors applied differently. The Sedation-Agitation Scale published by Richard Riker and colleagues in 1999 addressed some of this with a seven-point range that explicitly included dangerous agitation. Curtis Sessler and colleagues at Virginia Commonwealth University in Richmond developed the RASS with the explicit aim of building the assessment procedure into the instrument, and published its validation in the American Journal of Respiratory and Critical Care Medicine in 2002, with further psychometric testing showing that scores tracked changes in sedative dosing over time. Its adoption was accelerated by two developments already under way: trials of daily interruption of sedative infusions, reported by Kress and colleagues in 2000, which required a reliable way to describe arousal targets, and the CAM-ICU, published in 2001, which used the RASS as its assessability gate. The Society of Critical Care Medicine named it a preferred scale in the 2013 pain, agitation and delirium guidelines and again in the 2018 PADIS revision.