There are many ways to identify cardiac arrest, as follows: 1) Observe the patient’s consciousness, e.g., if the patient does not respond to shouts from both sides of the ear, the patient is usually unconscious. 2) Palpate the carotid artery, if the patient cannot palpate the carotid artery, cardiac arrest can also be identified. 3) If the patient has no heartbeat and is not breathing during auscultation, the electrocardiogram will show a straight line or no pulsatile electrical activity and the blood pressure cannot be measured. The patient’s pupils may be dilated. 5. The patient may also have very poor peripheral circulation.