Cardiogenic respiratory distress is defined as cardiogenic dyspnea caused by factors such as increased hydrostatic pressure, and is commonly associated with cardiogenic pulmonary edema due to left heart insufficiency, which leads to respiratory failure. So, what are the tests that should be done for patients with cardiogenic respiratory distress? The following is a brief introduction: 1. Doppler echocardiography: There are many red blood cells within the blood, which can reflect and scatter ultrasound and can be considered as a tiny source of sound. The probe is placed in the intercostal space without moving and emits ultrasound. When red blood cells flow in the heart or large blood vessels, the sound frequency scattered by the red blood cells changes. As the red blood cells move toward the probe, the reflected sound frequency increases, and vice versa, decreases. This difference in sound frequency between the red blood cells and the probe in relative motion is called the Doppler shift. It shows the speed and direction of blood flow and the nature of the blood flow. Doppler echocardiography is divided into pulsed Doppler echocardiography, continuous wave Doppler echocardiography, and color Doppler echocardiography. The most used is pulsed Doppler echocardiography, which can trace the real-time Doppler spectrum of blood flow at any point in the heart under two-dimensional image monitoring and positioning. 2.CT of the chest: CT of the chest is a method of examining the chest through X-ray computed tomography (CT). MRI of the chest: MRI of the chest is also called nuclear magnetic resonance. MRI diagnosis is widely used in clinical practice and is becoming more and more perfect, and has shown its superiority even though the time is short. In MRI image, the mediastinum can observe the septal tumor and its anatomical relationship with the surrounding blood vessels, and it can clearly show the invasion of the axilla, brachial plexus and vertebral canal by the swelling. It is more helpful in the diagnosis of hilar lymph node enlargement and central lung cancer. Cardiac macrovascular MRI has the advantages of rapid, time-saving and low patient pain. It can show the size and internal lumen of atrium and blood vessels, and can observe hemodynamic changes, which is helpful for functional diagnosis and can also identify abnormal tissues.