Doppler is commonly used to examine air embolism. Doppler auscultation of venous air embolism typically presents as a mill-wheel murmur (mill-wheelmur), but may be less sensitive. Signs are examined as follows: 1. The typical symptom is early loss of consciousness, which may or may not be accompanied by convulsions or other central nervous system symptoms. Mild signs and symptoms ranging from behavioral changes to mild hemiparesis may sometimes occur. 2. Excessive pulmonary distension alone or with gas embolism may produce mediastinal and subcutaneous emphysema. Pneumothorax is rare but more severe. Hemoptysis or bloody foamy sputum suggests lung damage. 3. Arterial gas embolism of medical origin is rare, but it should be suspected if the patient cannot regain consciousness after cardiac surgery. Most patients have an abrupt onset with sudden onset of irritability, extreme fear, dyspnea, cyanosis, severe chest and back pain, depression in the precordial region, and rapid descent into severe shock. On physical examination. The patient’s pulse is weak or even not palpable; blood pressure is decreased or even difficult to measure; pupils are dilated, arrhythmia is present, and a rough systolic grinding-wheel murmur ranging from a ticking sound to a typical systolic sound can be heard in the precordial region; sometimes intravascular bubbles can be felt moving under the fingers in the jugular vein. If the patient is in a high head position at the time of onset, there is a risk of cerebrovascular air embolism. At this point, the patient may have tonic or paroxysmal convulsions, loss of consciousness, or headache, dizziness, nausea, followed by dyspnea, weak breathing, general cyanosis, double vision, limb paralysis or convulsions, and finally go into shock.