AVPU Scale

Issues of Concern

Other scales for characterizing mental status have been developed. Selection of a specific scale depends on the clinical context, the patient's condition, and the information required for assessment.

The Glasgow Coma Scale (GCS) and the Richmond Agitation Sedation Scale (RASS) are 2 scales used to describe mental status. A study showed that GCS and RASS scores in admitted patients were significantly more accurate predictors of mortality than AVPU. Additionally, routine tracking of GCS and RASS scores on hospital wards may improve the identification of patients with deteriorating clinical status.[5] More recent evidence found that simplified consciousness assessment scales, including AVPU, demonstrated inferior prognostic validity compared with the GCS. Current evidence does not support replacing the GCS as the primary scale for consciousness assessment.[6]

The ACDU Scale (alertness, confusion, drowsiness, and unresponsiveness) is another 4-point scale similar to AVPU. A study showed that ACDU may be superior to AVPU for simple ward assessment of seriously ill patients. Additionally, median GCS scores associated with ACDU categories were 15, 13, 10, and 6. The median values of ACDU categories were more evenly distributed than those of AVPU when both scales were compared with GCS. This even distribution may indicate that ACDU is superior to AVPU in identifying early deterioration in consciousness among critically ill ward patients.[7]

The Simplified Motor Score (SMS) categorizes patients into 3 groups: obeys commands, localizes pain, and withdraws to pain or worse. The SMS is useful for evaluating patients in the prehospital and acute care settings for possible traumatic brain injury. A study found that the SMS provided the highest interrater reliability compared with the AVPU, GCS, and ACDU scales when assessing altered consciousness from traumatic and nontraumatic etiologies.[8]

Clinical Significance

Utility in First Aid, Prehospital Care, and Emergency Care

The AVPU scale is a quick and simple method for identifying altered mental status. The scale requires minimal training and may be used in first aid and prehospital settings, where any score below "A" is considered abnormal until proven otherwise. A score below "A" should prompt additional assessment or more definitive care. Emergency medical services personnel may begin with an AVPU assessment, followed by a GCS assessment if the AVPU score is below "A." Recent evidence suggests that, in prehospital trauma settings, AVPU recorded by Emergency Medical Technician-Basic (EMT-B) personnel is a dependable surrogate for GCS, correlates closely with GCS severity categories, and predicts 48-hour mortality while allowing more rapid assessment.[9]

Although less detailed than the GCS, the AVPU scale allows for more rapid assessment of a patient's level of consciousness. The AVPU scale was initially incorporated into the primary survey of trauma patients because a decreased level of consciousness may indicate inadequate cerebral perfusion or oxygenation.[10]

Clinical Applications in Hospital Care and Long-Term Healthcare Facilities

AMS is one of the strongest predictors of death among hospitalized patients. Healthcare professionals use the AVPU scale to identify patients at risk for abnormal levels of consciousness. The scale contributes to Rapid Response Activation Criteria and Early Warning Scores by detecting changes in a patient's physiologic status and helping identify and correct potentially life-threatening issues during hospitalization. Select patients, such as those in long-term care facilities or nursing homes, may have an AVPU score below A as a baseline finding. AVPU is designed for rapid screening and serial bedside assessment rather than detailed longitudinal neurologic monitoring.

Correlation to the Glasgow Coma Scale and Airway Protection

The AVPU scale demonstrates an approximate correlation with GCS scores, as outlined below:

• GCS 14 to 15: Alert
• GCS 10 to 13: Verbal response
• GCS 7 to 9: Response to pain
• GCS 3 to 6: Unresponsive [11]

Similar to the GCS, the AVPU scale can help identify patients at risk for airway compromise and aspiration. A GCS score of 8 or lower prompts consideration of airway protection, whereas AVPU scores of "P" or "U" may indicate impaired protective airway reflexes and inability to maintain a patent airway. However, overlap exists among intermediate AVPU categories, and corresponding GCS ranges may vary across patient populations.

Nursing, Allied Health, and Interprofessional Team Interventions

The AVPU scale provides a standardized method for rapidly assessing and communicating a patient's level of consciousness among healthcare professionals. Nurses, emergency medical services personnel, physicians, advanced practice clinicians, physician assistants, respiratory therapists, and other healthcare team members should perform serial AVPU assessments and promptly communicate any decline from baseline to facilitate timely evaluation and escalation of care. Effective interprofessional communication and coordinated care promote early recognition of neurologic deterioration, improve patient safety, and support optimal clinical outcomes.