Etiology: Air embolism can be seen in placenta praevia, uterine rupture, freehand placenta removal, internal inversion, fetal fragmentation, cesarean section, abortion, tubal aeration, vaginal douching, knee-chest position after delivery, etc. While performing the above operations, air can be brought in and accumulated in the uterine cavity and can be squeezed into the blood vessels through the open venous sinuses to cause air embolism when operating again. If the air enters the right atrium through the vein, it can cause air atresia between the pulmonary artery opening and the right ventricle, causing cyanosis and hypoxia; if the intravenous air embolism is retrograde to the superior vena cava or upward through the paraspinal plexus, the air can travel up to the brain, causing convulsions, etc.; if the patient has a combined atrial septal or ventricular septal defect, the intravenous air embolism can result in arterial air embolism. Clinical manifestations: 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. Excessive pulmonary distention 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. Arterial gas embolism of medical origin is rare, but should be suspected if there is a failure to regain consciousness after cardiac surgery. Most patients have an acute 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.