For patients with cardiac arrest, high-quality cardiopulmonary resuscitation is performed according to critical care management and Advanced Cardiac Life Support (ACLS). Rapid with powerful chest compression should be performed to maintain the heart's output and blood flow. An advanced airway should be established and adjust resuscitation based on collected clinical information. Transesophageal ultrasound examination is performed after the advanced airway is established without affecting the resuscitation. The investigators use the built-in ultrasound software (Philips QLAB 3D quantification advance, Philips Healthcare, USA, speckle tracking echocardiography (STE,Speckle tracking echocardiography)) to analyze stroke volume and cardiac output. The investigators collect the stroke volume and cardiac output at the chest compression position recommended by ACLS, as well as the stroke volume and cardiac output after adjusting the optimal chest compression position. The investigators expect it can increase the return of spontaneous circulation rate, survival rate, and neurological prognosis over time.