tailieunhanh - JUST THE FACTS IN EMERGENCY MEDICINE - PART 3

Các hiệu ứng pathophysiologic là do tắc nghẽn cơ học của hệ thống động mạch phổi và phát hành của vaso và các trung gian bronchoactive. Những trung gian-prostaglandin, catecholamine, serotonin, và co thắt phế quản nguyên nhân histamine | 102 SECTION 6 CARDIOVASCULAR DISEASES obesity burns malignancy estrogen use and other hypercoagulable states surgery in the last 3 months or lower extremity trauma. PATHOPHYSIOLOGY The pathophysiologic effects are caused by both mechanical obstruction of the pulmonary artery system and the release of vaso- and bronchoactive mediators. These mediators prostaglandins catecholamines serotonin and histamine cause bronchoconstriction as well as vasoconstriction of the pulmonary artery. Vasoconstriction is the predominant pathophysiologic effect leading to a ventilation perfusion mismatch. PE tends to be multiple and bilateral with the right lower lobe of the lung being the most commonly involved lung segment. CLINICAL FEATURES Common symptoms in decreasing order of frequency include dyspnea pleuritic chest pain anxiety cough hemoptysis sweats nonpleuritic chest pain and 5 Common signs in decreasing order of frequency include respirations 16 min rales pulse 100 min temperature phlebitis or DVT cardiac gallop diaphoresis edema and Pleural friction rub and wheezes are infrequent signs of PE. The presence or absence of any symptom or sign does not confirm or exclude the diagnosis of pulmonary embolism. Chest pain usually pleuritic and dyspnea are the most common symptoms and tachypnea respirations 16 min is the most common sign in the diagnosis of PE. Clinical evidence of DVT occurs in less than 50 percent of patients. However up to 80 percent of patients with PE have positive Massive PE 5 percent of cases presents with hypotension and hypoxia. DIAGNOSIS AND DIFFERENTIAL The diagnosis can be excluded or confirmed only with more sophisticated tests such as a ventilation perfusion V Q lung scan or pulmonary angiography. Hypoxia occurs in about 90 percent of patients with PE but the PaO2 may be normal. While a PaO2 of 80 to 90 mmHg is 90 to 95 percent sensitive in identifying patients with PE it is only 50 percent The