Sedation assessment scales provide standardized tools for evaluating a patient's level of consciousness and sedation depth. The Richmond Agitation-Sedation Scale (RASS, -5 to +4) ranges from unarousable (-5) through calm and alert (0) to combative (+4) and is widely used in ICU settings. The Ramsay Sedation Scale (1-6) grades levels from anxious/agitated (1) through no response (6). The Modified Aldrete Score (0-10) assesses post-anesthesia recovery across activity, respiration, circulation, consciousness, and SpO2; score ≥9 indicates readiness for PACU discharge. The Glasgow Coma Scale (3-15) assesses eye opening, verbal response, and motor response and is used for neurological injury, not pharmacological sedation. Accurate sedation assessment is essential for titrating medications to the desired level (typically RASS -2 to 0 for light ICU sedation), avoiding over-sedation (which increases ventilator days, ICU stay, and delirium risk), and ensuring patient safety. The ascending reticular activating system (ARAS) in the brainstem maintains wakefulness; sedative agents suppress ARAS activity in a dose-dependent manner.