Cognitive Bias in Field Decisions

Why this matters

The common thinking error is locking onto the first idea. That idea is often the dispatch code. This is anchoring. Confirmation bias then looks only for facts that fit. It skips clear lungs that argue against heart failure. Premature closure means you stop after the first treatment. The sugar may rise while the face is still weak. Diagnostic momentum means your label sticks at the hospital. This is not the same as being careless. Under time pressure, people take shortcuts. Name the first story as a guess. Treat the life threat first. Then ask out loud what else this could be.

Clinical sequence

1. Treat life threats first. Thinking checks come after the airway is open and major bleeding is controlled.
2. Say the working idea in one sentence. This may look like panic, heart failure, intoxication, or a urinary infection.
3. Do the check that could disprove that idea. Sugar, a 12-lead, lung sounds, temperature, and a second set of vital signs are the usual tools. Use ultrasound only if you are trained and your protocol allows it.
4. Reassess after treatment. If they still look sick, you do not have a finished diagnosis. You have a patient who needs transport.

Teaching points

• Anchoring. The first impression sticks. Dispatch said panic attack, so nobody gets a 12-lead. Do not skip the 12-lead because of the dispatch code.
• Confirmation. You collect only the facts that agree. You skip the finding that argues. Look for the finding that would change your mind.
• Premature closure. The sugar is treated, and the stroke is still there. Naloxone is given, and the trauma is still there. Do not stop at the first fix.
• Availability. Last week’s pulmonary embolism, a clot in the lung, makes every fast breather a clot this week. Or you never look for uncommon causes because you rarely see them.
• Diagnostic momentum. Your label becomes the hospital’s first sentence. Say “weak, low blood pressure, source unclear.” Do not say “just a urinary infection” when you do not know.

Common errors

• Skipping the 12-lead because the patient is “anxious.”
• Calling leftover one-sided weakness “still waking up” after dextrose.
• Giving albuterol for wet lungs and high blood pressure because you heard a wheeze.
• Writing the dispatch code as the impression without a new set of vital signs.

Practice

Related: Altered Mental Status Framework, Stroke Mimics, ACS Without Chest Pain.

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

• NASEMSO National Model EMS Clinical Guidelines (2022) — reassessment after intervention is part of every pathway; your protocol still decides care
• Croskerry — The importance of cognitive errors in diagnosis (Acad Med 2003) — anchoring, confirmation, premature closure; named traps, not a personality test
• NAM/IOM — Improving Diagnosis in Health Care (2015) — diagnostic error is common; systems and rechecking beat “try harder”