How to Diagnose Cardiac Arrest

Diagnosing cardiac arrest requires quick and decisive action. Ideally, a diagnosis should be made within 30 seconds based on the following key signs:

Key Diagnostic Criteria

1. Sudden loss of consciousness: A previously alert patient becomes unresponsive and does not react to verbal stimuli.

2. Absence of pulse: There is no detectable pulse in major arteries such as the carotid or femoral artery.

3. Dilated pupils: The patient's pupils appear enlarged and unresponsive to light.

4. No breathing or agonal breathing: The patient has stopped breathing or is exhibiting gasping, irregular breaths.

Immediate Action is Critical

The first two signs—loss of consciousness and absence of a pulse—are the most crucial indicators of cardiac arrest. Healthcare providers should not delay intervention by repeatedly measuring blood pressure, listening to heart sounds, or waiting for an ECG to confirm the diagnosis. Every second counts in improving the patient's chance of survival.

Why Waiting for Pupil Changes is Not Advised

While pupil dilation is a significant clinical sign, it typically occurs later and can be influenced by medications or other factors. Therefore, clinicians should not wait for changes in pupil size before initiating life-saving measures.