A point-of-care echocardiogram can also assess for causes of obstructive shock. The vena cava would be dilated due to the obstruction. In pulmonary embolism, the right ventricle will be dilated. Other findings include paradoxical septal motion or clots in the right heart or pulmonary artery. Echocardiography can assess for pericardial effusion. In tamponade, collapse of the right atrium and ventricle would be seen due to pressure in the pericardial sac.A chest X-ray can rapidly identify a pneumothorax, seen as absence of lung markings. Ultrasound can show the lack of lung sliding. However, imaging should not delay treatment. CT angiography is the standard of diagnosis of pulmonary embolism. Clots appear in the vasculature as filling defects. Treatment
In any type of shock, rapid treatment is essential. Delays in therapy increase the risk of mortality. This is often done as diagnostic assessment is still occurring. Resuscitation addresses the ABCs - airway, breathing, and circulation. Supplemental oxygen is given, and intubation is performed if indicated. Intravenous fluids can increase blood pressure and maintain blood flow to organs.However, fluids should be given with caution. Too much fluid can cause overload and pulmonary edema. In some cases, fluids may be beneficial. Fluids can improve venous return. For example, tamponade prevents normal cardiac filling due to pressure compressing the heart. In this case, giving fluids can improve right heart filling. However, in other causes of obstructive shock, too much fluid can worsen cardiac output. Thus, fluid therapy should be monitored closely.After these stabilizing measures, further treatment depends on the cause.
Most often, the obstruction is a blood clot that traveled from elsewhere in the body. Most commonly, this is from a deep vein thrombosis (DVT) in the legs or pelvis. Risk factors are conditions that increase the risk of clotting. This includes genetic (factor V Leiden) and acquired conditions (cancer). Trauma, surgery, and prolonged bed-rest are common risks. Covid-19 is a recent risk factor.This obstruction increases the pulmonary vascular resistance. If large enough, the clot increases the load on the right side of the heart. The right ventricle must work harder to pump blood to the lungs. With back-up of blood, the right ventricle can begin to dilate. Right heart failure can ensue, leading to shock and death.A PE is considered "massive" when it causes hypotension or shock. A submassive PE causes right heart dysfunction without hypotension. Cardiac tamponade
A pericardial effusion is fluid in the pericardial sac. When large enough, the pressure compresses the heart. This causes shock by preventing the heart from filling with blood. This is called cardiac tamponade. The chambers of the heart can collapse from this pressure. The right heart has thinner walls and collapses more easily. With less venous return, cardiac output decreases. The lack of blood flow to vital organs can cause death.Various conditions can cause a pericardial effusion. Inflammation of the pericardium is called pericarditis. This is caused by infection, renal failure or autoimmune disease. Trauma can cause blood to fill the pericardium. Cancer can also cause effusions.