Acute pulmonary embolism: due to thromboembolic disease

2021-08-04 11:40 AM

The goal of treatment for acute pulmonary embolism is to rapidly relieve pulmonary embolism, either by thrombolysis, surgical embolization, or mechanical catheter ablation

Acute pulmonary embolism increases right ventricular posterior load and right ventricular end-diastolic and end-systolic volumes and decreases right ventricular stroke volume. These changes can reduce left ventricular preload and impair left ventricular function because of ventricular failure and decreased cardiac output with circulatory failure may occur. Fluid loading increases right ventricular end-diastolic volume and may increase cardiac output by the Franck-Starling mechanism, but it can also increase left septal displacement, thereby impairing ventricular diastolic function left.

Pulmonary embolism is the occlusion of at least one pulmonary artery or pulmonary artery branch, usually caused by a thrombus moving up from the deep vein. This is a fairly common disease but difficult to diagnose because it is easily confused with other diseases. other. The ability to diagnose and treat depends on the equipment of each medical facility. Even with adequate equipment, if you don't think about it, you can't diagnose pulmonary embolism. Patients without proper diagnosis and treatment have a mortality rate of up to 30%.

Clinical symptoms of pulmonary embolism

Patients may present with the following nonspecific symptoms of unknown cause:

Shortness of breath; pleuritic chest pain; coughing up blood, fainting; hypotension and/or shock.

Have one or more thromboembolism-embolism risk factors

After surgery for knee replacement, hip replacement, colon tumor, uterine fibroids, patients with terminal cancer, lying for a long time, pregnancy, postpartum, pre-existing coagulopathy...

Calculate Wells Score.

Table of  Wells. Score










History of thrombophlebitis or pulmonary embolism



Immobilization for > 3 days consecutively, or postoperatively for 4 weeks (major surgery)



Tachycardia > 100 beats/min



Signs of thrombophlebitis of the lower extremities on examination (one leg is swollen, hot, painful, and the dorsal pulse is obvious)




Little thought of other diagnoses (when excluding other conditions)


Wells > 4 points: high probability of pulmonary embolism, prompt imaging studies to confirm the diagnosis.

Wells < 4 points: low pulmonary artery capacity, need to do more D-dimer, if D-dimer < 500 μg/ml, the pulmonary artery can be excluded; If the D-dimer is > 500 μg/ml, additional imaging studies are required for diagnosis.

Diagnostic protocol based on Wells score and D-dimer

Diagnosing and treating pulmonary infarction

Subclinical symptoms of pulmonary embolism

Electrocardiogram: tachycardia, atrial fibrillation, right bundle branch block, severe s deep D1, deep D3, T negative D3 or T negative in right precordial leads V1-V3.

Arterial blood gases: respiratory alkalosis and shunt pH increased, PCO 2 decreased, PO 2 decreased, HCO 3 normal,

A-aO 2 > 50 (in patients with COPD, PCO 2 may be normal and HCO 3 elevated).

Chest X-ray: pleural effusion, unilateral elevation of diaphragm, ... D.dimer: D-dimer < 500μg/ml and Wells < 4 can rule out pulmonary artery occlusion.

Doppler ultrasound of the lower extremities: possible deep vein thrombosis.

CT often pulmonary vessels: low diagnostic value, see blood clots in the blood vessels is the definitive diagnosis; If no thrombus is seen, additional deep vein Doppler ultrasound should be performed to rule out pulmonary embolism.

MsCT pulmonary angiography is the first test to replace pulmonary angiography. The diagnosis is confirmed when there is a thrombus in the pulmonary artery.

Definite diagnosis

Chest pain, difficulty breathing, coughing up blood, unexplained fainting.

There is a pathology of thromboembolism: after surgery in the pelvic region, cancer, lying for a long time.

Electrocardiogram, X-ray changes.

D-dimer positive.

Diagnostic imaging of pulmonary artery thrombus.

Differential diagnosis

Acute coronary syndrome: chest pain suggestive of coronary artery disease, with risk factors for coronary artery disease (hypertension, diabetes, dyslipidemia, smoking, family history), electrocardiogram suggests, troponin and CK, CK-MB.

Pneumonia, pleurisy: cough, high fever, white blood cell count increased, chest X-ray shows pneumonia.

Aortic dissection: hypertension, asymmetric extremity pulse, signs of peripheral ischemia,

Wide mediastinal chest x-ray, contrast-enhanced CT of the aorta.

Pneumothorax: sudden pain in young people, poor alveolar murmur on one side,

Chest X-ray with pneumothorax.

Acute pulmonary edema: heart failure, chronic renal failure, moist rales in both lungs.

Treatment of pulmonary embolism

Apply treatment depending on the actual conditions of the hospital. Requires careful examination of the patient's contraindications to anticoagulants and fibrinolytic prior to administration.

Treatment of pulmonary embolism without hypotension

Bed immobilizes 24-48 hours until anticoagulation is effective.

Breathe 0 2 if SpO 2 < 95%.

Enoxaparin (Lovenox) 1mg/kg subcutaneously 2 times/day (from day 1), stopped after 5 days of treatment and INR 2-3 consecutively for 2 days.

Sintrom 1 mg/day (from the first day), do the first INR 3 days after starting treatment, adjust up and down the dose of sintrom to 0.5 mg/day to achieve the target INR 2-3. If INR > 3, no noticeable bleeding, skip next dose, then return to reduced dose by 1/8 tablet or alternate eg 1/4 - 1/8 - 1/4 - 1/8 pellets.

Sodium chloride 0.9% X 500ml (20ml intravenous infusion per hour).

Treatment of pulmonary embolism with hypotension or shock

Respiratory resuscitation if there is respiratory failure.

Securely place a peripheral IV line at a site where compression is possible (avoid central venous or arterial catheters).

Heparin: 5000UI bolus before Actilyse, after the end of Actilyse, the maintenance infusion is 500UI/kg/day (maintained for at least 5 days, then stop when vitamin K resistance has results).

Intravenous Haes-steril 6% 500ml over 20 minutes (then control the fluid).

Dobutamine: 5μg/kg/min (increase 2.5μg/kg/min after 10-15 minutes) or dopamine 5μg/kg/min (increment 2.5μg/kg/min after 10-15 minutes). Target blood pressure > 100/70 mmHg.

Review the checklist of contraindications to thrombolytics before deciding to administer Actilyse to the patient.

Actilyse: 0.6mg/kg in 20 minutes by electric syringe in the appendix.

Vitamin K-resistant pillows such as PE do not drop blood pressure (from the first day).

If the patient has a contraindication to fibrinolysis or the failure of thrombolytic therapy, the patient should be transferred to a facility capable of thoracotomy to remove thrombus.


Physiotherapy avoids lying down for a long time.

For patients with risk factors, prophylactic anticoagulation with low-molecular-weight heparin or vitamin K antagonists is required.

After surgery, the patient should be taught to walk early.