Altered Mental Status

Altered mental status (AMS) is a description of a patient’s mental status when it deviates from a patient’s mental baseline. Said another way, the patient may have been acting mentally ‘normal’, and now they are acting ‘abnormal.’ The first step in understanding AMS is determining the patient’s baseline mental status. Asking family, friends, and others on scene as well as using scene clues to point you toward the patient’s normal level of functioning can be useful in making a baseline determination. Note that some patients may be altered at baseline and determining if they are indeed suffering from AMS can be difficult to impossible without someone else on scene who knows the patient’s mental status at baseline.

Once the initial presence of AMS is suspected, it is time to start collecting clues as to the cause of AMS that can lead to a working diagnosis, and hopefully a treatment plan. Many experienced EMS field providers advocate for the use of the “O2, Glucose, Pump, SITS” mnemonic, developed by an ER physician and EMS medical director in Oregon, Dr. Jeff Disney. It provides a nice cognitive aid to help systematically think through many of the common causes for AMS. The mnemonic is a prioritized set of steps to assess for the presence of life-threatening causes of AMS.

Let’s break it down. The team leader should delegate the assessments and treatments of any significant findings. Something else to remember is that once you find something significant it is still important to continue down and complete the mnemonic as to not miss possibly combining or multiple factors.

O2 – Check oxygenation.

      • Is the airway open and clear?
      • Are they breathing adequately?
      • What is the SpO2?

Glucose – Check the capillary blood glucose level.

Pump – Is there perfusion to the brain?

      • Check pulse.
      • Check blood pressure.
      • Check skin condition.


      • Structural – assess for structural damage to the head such as from trauma or internally from a stroke
      • Infection – explore major sources of infection (urine/UTI, respiratory/pneumonia, surgical/healing injury site, pressure sores, meningitis, recent illness, or new antibiotic prescriptions)
      • Toxin – overdose/underdose (illicit drugs, prescription drugs, alcohol withdrawal) or possibly an environmental toxin (carbon monoxide)
      • Seizure / Psychiatric – Seizures are usually a symptom of something else (i.e., hypoxia/trauma) or possibly a patient condition.
        • Psychiatric – ask about psychiatric history and recent behavior.

Now you try. On your next dispatch for “unknown problem” or “altered mental status” give O2, Glucose, Pump, SITS a try.

Altered Mental Status Skills Verification Table


O2, Glucose, Pump, SITS





5 (instructor)



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Oregon EMS Psychomotor Skills Lab Manual Copyright © 2023 by Chris Hamper, BS, NRP; Carmen Curtz, Paramedic, BS; Holly A. Edwins, Paramedic, B.S.; and Jamie Kennel, PhD, MAS, NRP is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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