Beware of the "invisible killer" - prevention and identification of acute pulmonary embolism

Author: Zhu Dandan, attending physician, Xuanwu Hospital, Capital Medical University, PhD

Reviewer: Wang Changyuan, Chief Physician, Xuanwu Hospital, Capital Medical University

In daily life, we may encounter various critical illnesses, among which acute pulmonary embolism is a serious and life-threatening disease, which can manifest as dyspnea, cough, syncope and hemoptysis. But sometimes its symptoms are not typical and are easily ignored, which can cause cardiac arrest and death of patients. Therefore, it is called the "invisible killer" by the medical community. With the change of lifestyle and the aging of the population, the incidence of acute pulmonary embolism has increased year by year. If not treated in time, the mortality rate of the disease can reach 25% to 30%.

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1. Definition and hazards of acute pulmonary embolism

Acute pulmonary embolism refers to a clinical syndrome in which various emboli enter the pulmonary artery and block the pulmonary artery or its branches. Pulmonary embolism includes pulmonary thromboembolism, amniotic fluid embolism, fat embolism and tumor embolism, among which pulmonary thromboembolism is the most common. The thrombus often originates from the veins of the lower limbs. There are many reasons for the formation of thrombus, the most common of which are long-term bed rest, orthopedic surgery and trauma.

Pulmonary embolism mainly has adverse effects on the human body's circulatory and respiratory systems. Imagine that after the lower limb vein thrombosis breaks off, it will flow into the pulmonary artery with the blood, causing blockage of the main trunk or branches of the pulmonary artery, and imbalance of ventilation and blood flow in the lung tissue, thereby affecting the exchange of gases in the human body, causing varying degrees of hypoxia in various tissues in the body. At the same time, blood clots blocking the pulmonary artery will cause pulmonary hypertension, which in turn affects heart function, easily causing various arrhythmias or cardiac arrest, causing serious harm to the human body.

In short, acute pulmonary embolism may lead to a variety of serious complications such as cardiac arrest, pulmonary infarction and pulmonary hypertension, and may even be life-threatening. Therefore, if you experience symptoms of acute pulmonary embolism such as dyspnea, cough, syncope and hemoptysis, you should seek medical attention immediately.

2. Risk factors for acute pulmonary embolism

Any factors that can lead to hypercoagulable state of blood, slow venous blood flow and vascular endothelial damage are risk factors for acute pulmonary embolism, which generally include two categories: genetic and acquired factors.

Genetic factors are determined by the genes of the parents and cannot be changed. If you are a person with a hereditary tendency to thrombosis, your risk of acute pulmonary embolism will be significantly increased. For people with a family history of thrombosis, genetic counseling and regular examinations are recommended to detect and take preventive measures in time. Although hereditary factors cannot be avoided, regular examinations can help such patients better control the risk.

Acquired factors refer to various factors acquired after birth that are prone to cause lower extremity venous thrombosis, most of which are temporary or reversible. For example, long periods of sitting, whether on an airplane, train, or working in an office, the lower limbs are inactive for a long time, which may lead to slower blood circulation in the lower limbs and increase the risk of lower extremity venous thrombosis and pulmonary embolism. Therefore, it is recommended that people who sit for a long time should move appropriately and change their body position to promote blood circulation and reduce the risk of acute pulmonary embolism. In addition, surgery, trauma, long-term bed rest, and tumors are also acquired factors, which will increase the risk of thrombosis. In these cases, doctors may recommend that patients get out of bed early after surgery and use anticoagulants to prevent thrombosis.

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In addition, obesity and smoking are also risk factors for acute pulmonary embolism. Therefore, quitting smoking and exercising appropriately can help reduce the risk of acute pulmonary embolism.

3. Symptoms and identification of acute pulmonary embolism

Typical symptoms of acute pulmonary embolism include dyspnea, cough, hemoptysis, dizziness, chest pain, tachycardia, swelling or pain in the lower limbs, etc. Among them, dyspnea often occurs suddenly, and in severe cases, the patient may feel suffocated.

It should be noted that the symptoms of acute pulmonary embolism may vary from person to person. Some people may experience mild dyspnea, while others may experience severe symptoms such as cardiac arrest; some people may have a dry cough, while others may cough up bloody sputum; and a few patients may have syncope without other clinical manifestations. In addition, the severity of symptoms may change over time, and sometimes the condition may suddenly worsen. Therefore, if we have any unusual symptoms, especially those with the above risk factors, we should go to the hospital immediately.

In some cases, acute pulmonary embolism may lead to serious complications, such as cardiac arrest or pulmonary infarction. These complications may lead to death and require immediate medical intervention.

Since the symptoms of acute pulmonary embolism are similar to those of common diseases such as chronic bronchitis, it is easy to be misdiagnosed. According to statistics, only 7% of patients with acute pulmonary embolism are diagnosed before death. Therefore, it is emphasized again that if you suddenly experience symptoms such as dyspnea, chest pain, and hemoptysis, you should go to the hospital immediately, because timely treatment can greatly reduce the mortality and recurrence rate of acute pulmonary embolism.

4. Diagnosis and treatment of acute pulmonary embolism

After a patient suspected of acute pulmonary embolism is admitted to the hospital, the doctor will make a comprehensive diagnosis based on clinical symptoms, electrocardiogram, D-dimer and CT pulmonary angiography, among which CT pulmonary angiography is an important basis for the clinical diagnosis of acute pulmonary embolism. CT pulmonary angiography is like taking a high-definition movie of the pulmonary blood vessels. Doctors can find the filling and defects of the pulmonary arteries, the location and size of the thrombus, etc. by watching the "movie". After the patient is diagnosed with acute pulmonary embolism, the doctor needs to closely monitor the patient's condition and vital signs. A treatment plan is formulated according to the condition, including anticoagulant therapy, intravenous thrombolysis or interventional therapy. Anticoagulant therapy is to prevent blood coagulation by using drugs such as heparin and warfarin, thereby reducing the risk of thrombosis. If the patient is hemodynamically unstable, thrombolytic therapy such as urokinase can be used to quickly dissolve the thrombus and restore blood flow. However, thrombolytic therapy has the risk of bleeding and is not suitable for all patients. For example, patients with contraindications to thrombolysis or a history of more than 2 weeks are not suitable for thrombolytic therapy. Whether it is anticoagulant therapy or thrombolytic therapy, the patient's coagulation should be closely observed to prevent the risk of bleeding. The most commonly used interventional treatment is local embolectomy through the arterial catheter, which is to enter the pulmonary artery through the arterial catheter to perform local thrombolysis, accelerate the dissolution of thrombus, and quickly restore the normal pulmonary circulation. It can also enter the pulmonary artery and use negative pressure suction thrombectomy, hydrodynamic thrombectomy, and fragmentation thrombectomy to quickly aspirate the thrombus in the pulmonary artery or dissolve the thrombus, so as to restore pulmonary blood flow as soon as possible. Interventional treatment is suitable for patients with high-risk pulmonary embolism, medium- and high-risk pulmonary embolism with hemodynamic deterioration, and patients with contraindications or failure of thrombolysis.

5. Prevention of Acute Pulmonary Embolism

Although we cannot change the genetic factors that predispose to acute pulmonary embolism, we can reduce the risk of acute pulmonary embolism by changing acquired factors. Among them, changing lifestyle is the key to preventing acute pulmonary embolism. For example, avoid sitting for long periods of time, exercise regularly, drink plenty of water, etc. to prevent the blood from being too viscous. For high-risk groups, such as postoperative patients, pregnant women and bedridden patients, more active preventive measures should be taken, such as wearing medical elastic stockings, anticoagulant therapy, etc. In addition, the publicity of relevant knowledge on the prevention of acute pulmonary embolism should be strengthened to enhance the public's awareness of prevention.

Each of us should clearly realize that acute pulmonary embolism is a serious disease that can be prevented. Deepening the understanding of this disease, taking effective preventive measures (such as improving lifestyle), and timely treatment can effectively reduce the incidence and mortality of acute pulmonary embolism. Let us fight this "invisible killer" together and protect the health of ourselves and our families!