Richmond Agitation Sedation Scale Calculator
Score ICU patient sedation and agitation levels using the RASS scale. Enter values for instant results with step-by-step formulas.
Calculator
Adjust values & calculateModerately above target. Assess for reversible causes of agitation (pain, delirium, hypoxia, full bladder). Administer sedative bolus and consider infusion adjustment.
Formula
The RASS is a 10-point scale assessed in three sequential steps: (1) observe for spontaneous activity, (2) verbal stimulation if not spontaneously alert, (3) physical stimulation if no response to voice. Positive scores indicate agitation, zero indicates alert and calm, and negative scores indicate sedation levels.
Last reviewed: January 2026
Worked Examples
Example 1: Post-Intubation Sedation Assessment
Example 2: Agitated Delirious Patient
Background & Theory
The Richmond Agitation Sedation Scale Calculator applies the following established principles and formulas. Health and medicine calculators are grounded in validated physiological measurement methods established through decades of clinical research. Body Mass Index, or BMI, is calculated by dividing weight in kilograms by height in meters squared (kg/m²), a formula originating from Adolphe Quetelet's 19th-century statistical work and later codified by the WHO into standard classifications: underweight below 18.5, normal weight 18.5 to 24.9, overweight 25 to 29.9, and obese at 30 and above. Basal Metabolic Rate quantifies the minimum energy required to sustain life at rest. The Mifflin-St Jeor equation, published in 1990 and widely regarded as the most accurate for most adults, calculates BMR as (10 × weight in kg) + (6.25 × height in cm) − (5 × age) ± sex adjustment. The older Harris-Benedict equations, revised in 1984 by Roza and Shizgal, remain in common use. Total Daily Energy Expenditure is derived by multiplying BMR by a physical activity factor ranging from 1.2 for sedentary individuals to 1.9 for extremely active ones, following the methodology validated by doubly labeled water studies. Body fat percentage can be estimated without laboratory equipment using the U.S. Navy circumference method, which uses neck, waist, and hip measurements, or via BMI-derived equations adjusted for age and sex. The Jackson-Pollock skinfold method offers higher precision with calipers. Blood pressure classification, according to the American College of Cardiology and the 2017 ACC/AHA guidelines, defines normal as below 120/80 mmHg, elevated as 120 to 129 systolic, and hypertension stage 1 as 130 to 139 systolic or 80 to 89 diastolic. Target heart rate zones for aerobic exercise are derived from maximum heart rate estimates, most commonly using the formula 220 minus age in years, with moderate-intensity training typically defined as 50 to 70 percent of maximum heart rate and vigorous intensity at 70 to 85 percent, consistent with CDC and American Heart Association guidelines. These thresholds guide safe and effective cardiovascular conditioning.
History
The history behind the Richmond Agitation Sedation Scale Calculator traces back through the following developments. The history of health measurement stretches back to ancient Greece, where Hippocrates around 400 BCE laid the foundation for observational medicine by systematically recording patient symptoms, diet, and environment. His humoral theory, though scientifically superseded, established the principle that the body operates as an interconnected system subject to measurable imbalance. The transformation toward modern medicine accelerated in the 19th century. Louis Pasteur and Robert Koch developed germ theory in the 1860s and 1870s, identifying microorganisms as disease agents and enabling targeted interventions. Florence Nightingale, working during the Crimean War in the 1850s, introduced statistical analysis to nursing practice, demonstrating through data visualization that sanitation reduced mortality. Her work is foundational to evidence-based health measurement. The discovery of vitamins in the early 20th century, beginning with Casimir Funk's coinage of the term in 1912 and culminating in the isolation of vitamins A through K, created the field of nutritional science and gave rise to dietary reference intake frameworks. The World Health Organization, founded in 1948, subsequently established global standards for health metrics, disease classification through the International Classification of Diseases, and recommended daily allowances. The BMI as a clinical screening tool gained traction in the 1970s through Ancel Keys' large-scale epidemiological work, which validated Quetelet's index as a population-level obesity indicator. Through the 1980s and 1990s, the Framingham Heart Study produced landmark data linking cholesterol, blood pressure, and lifestyle factors to cardiovascular disease risk, directly shaping the numeric thresholds still used in health calculators. The evidence-based medicine movement, formalized by Gordon Guyatt and colleagues at McMaster University in the early 1990s, demanded that all health recommendations derive from systematically graded clinical evidence. The digital health era beginning in the 2000s brought these formulas to consumer devices, wearable sensors, and smartphone applications, expanding access to health self-monitoring on a global scale and enabling population-level data collection that continues to refine clinical reference ranges.
Frequently Asked Questions
Sources & References
- 1Sessler CN et al. The Richmond Agitation-Sedation Scale. American Journal of Respiratory and Critical Care Medicine, 2002
- 2Devlin JW et al. Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption (PADIS). Critical Care Medicine, 2018
- 3MDCalc - Richmond Agitation-Sedation Scale (RASS)
Formula
RASS Score: -5 (unarousable) to +4 (combative)
The RASS is a 10-point scale assessed in three sequential steps: (1) observe for spontaneous activity, (2) verbal stimulation if not spontaneously alert, (3) physical stimulation if no response to voice. Positive scores indicate agitation, zero indicates alert and calm, and negative scores indicate sedation levels.
Worked Examples
Example 1: Post-Intubation Sedation Assessment
Problem: A mechanically ventilated patient is receiving propofol and fentanyl infusions with a RASS target of -2 (light sedation). When called by name, the patient briefly opens eyes and makes eye contact for 5 seconds before closing eyes again.
Solution: Step 1: Patient is not spontaneously alert (not RASS 0 to +4)\nStep 2: Verbal stimulation - patient opens eyes briefly with eye contact < 10 seconds\nThis matches RASS -2: Light Sedation\nTarget RASS: -2\nDifference: 0 (at target)
Result: RASS Score: -2 (Light Sedation) | At Target | Continue current sedation regimen
Example 2: Agitated Delirious Patient
Problem: A patient is pulling at their endotracheal tube and attempting to climb out of bed. The RASS target is -1 (drowsy). Assess the RASS score and determine the gap from target.
Solution: Step 1: Observe patient without stimulation\nPatient is pulling at tubes and attempting to get out of bed\nThis matches RASS +3: Very Agitated (pulls/removes tubes, aggressive)\nTarget RASS: -1\nDifference: +3 - (-1) = 4 points above target
Result: RASS Score: +3 (Very Agitated) | 4 points above target | Assess for pain/delirium, administer sedative
Frequently Asked Questions
What is the Richmond Agitation-Sedation Scale?
The Richmond Agitation-Sedation Scale (RASS) is a 10-point validated assessment tool used to measure the level of agitation or sedation in ICU patients. Developed by Sessler and colleagues at Virginia Commonwealth University in 2002, it uses a scale ranging from +4 (combative) through 0 (alert and calm) to -5 (unarousable). The RASS was specifically designed for ICU patients and has become the most widely used sedation assessment tool in critical care settings worldwide. It is recommended by the Society of Critical Care Medicine in their Pain, Agitation, and Delirium (PAD) guidelines as the preferred sedation scale. The RASS takes approximately 20 seconds to perform and requires no special equipment, making it practical for frequent bedside assessments.
What causes agitation in ICU patients?
Agitation in ICU patients, reflected by positive RASS scores, has multiple potential causes that should be systematically evaluated before simply increasing sedation. The most common cause is undertreated pain, which should be assessed using validated pain scales like the Critical-Care Pain Observation Tool (CPOT) or Behavioral Pain Scale (BPS). Delirium is another major cause of agitation and requires targeted treatment rather than increased sedation. Physiological causes include hypoxia, hypercapnia, hypoglycemia, urinary retention, constipation, and fever. Environmental factors such as noise, sleep disruption, and physical restraints can also contribute. Medication-related causes include alcohol or drug withdrawal, paradoxical reactions to benzodiazepines, and akathisia from antipsychotics. Addressing the underlying cause is always preferable to simply masking agitation with sedatives.
What is the difference between RASS and the Riker Sedation-Agitation Scale?
Both the RASS and the Riker Sedation-Agitation Scale (SAS) are validated ICU sedation assessment tools, but they have important differences. The RASS uses a 10-point scale from -5 to +4 with discrete, well-defined behavioral descriptors at each level, while the SAS uses a 7-point scale from 1 (unarousable) to 7 (dangerous agitation). RASS was specifically designed with a standardized assessment procedure that includes sequential observation, verbal stimulation, and physical stimulation steps, making it more reproducible between assessors. The RASS has demonstrated excellent inter-rater reliability with weighted kappa values of 0.91 to 0.94. The SAS has slightly less granularity on the sedation end of the spectrum. The RASS is more widely used in current practice and is specifically recommended by the 2018 PADIS guidelines, partly because the CAM-ICU delirium tool was validated using RASS as its companion sedation assessment.
How accurate are the results from Richmond Agitation Sedation Scale Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
Can I use Richmond Agitation Sedation Scale Calculator on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.
References
- Sessler CN et al. The Richmond Agitation-Sedation Scale. American Journal of Respiratory and Critical Care Medicine, 2002
- Devlin JW et al. Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption (PADIS). Critical Care Medicine, 2018
- MDCalc - Richmond Agitation-Sedation Scale (RASS)
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy