PULMONARY EMBOLISM

PULMONARY EMBOLISM
When a major embolus becomes impacted in a large branch of the pulmonary artery, the patient is struck down without warning and may expire in a few minutes. When the embolus is smaller survival is possible, but despite skilled treatment the patient's life is commonly in danger for some days. For the largest emboli no treatment is available short of the heroic operation of embo-lectomy, for which surgical facilities are rarely at hand at the moment of catastrophe. The essence of treatment in this condition lies in prevention, and too much stress cannot be laid on prophylaxis.
The patient who survives such an embolic accident is shocked, dyspnoeic, apprehensive and in pain. The most effective immediate remedies are 15 to 30 mg of morphine subcutaneously and the liberal administration of oxygen. In desperately shocked patients the giving of analeptic drugs, such as nikethamide, 2 to 5 ml. intravenously, may be of value. Relief for the labouring right heart may be afforded by a prompt and rapid venesection, the indication being the degree of distension of the veins in the neck. Anticoagulant treatment should be instituted at once, starting with 10,000 to 15,000 units of heparin intravenously. A large pleural effusion develops in some patients surviving a major pulmonary infarction and this may require aspiration later.

Prophylaxis.—The essential causal factor in pulmonary embolism is the migration of a clot from either the venous system or the right atrium, through the right ventricle to the pulmonary artery. Formation of clots in the right auricle is favoured by atrial fibrillation, whether of rheumatic or other origin, while venous thrombosis occurs under a wide variety of conditions associated with immobilization in bed, with or without previous surgical operation. Much can be done to prevent the development of such clots by prophylactic anti-coagulant treatment. There is ample evidence, for example, that the incidence of pulmonary infarction subsequent to gynaecological and orthopaedic operations, particularly in elderly people who have sustained a fractured neck of femur, can be dramatically reduced by such treatment. Phlebothrombosis in leg veins commonly occurs in patients confined to bed in medical wards and attention to mobilization of the patient and daily examination of the legs for evidence of venous thrombosis or tenderness may forestall serious embolic accidents, though even with the greatest care these may occur. The administration of anticoagu¬lants to such individuals as a routine is advisable. Patients with atrial fibrillation, who are all liable to pulmonary and systemic embolism, should be afforded protection by long-term anticoagulant therapy, which reduces the incidence of such embolic incidents to ten per cent. of that in the unprotected.