[Alveolar-arterial oxygen gradient in patients with clinical symptoms of pulmonary embolism]

The accurate detection of pulmonary embolism is possible by means of non-invasive but very expensive ventilation-perfusion lung scanning or invasive and with high rate of complications pulmonary angiography. Thus monitoring of many clinical and biochemical parameters has been recently attempted to increase the probability of correct diagnosis of pulmonary embolism. The alveolar-arterial oxygen gradient is a more sensitive indicator of disturbance in oxygenation than occurrence of hypoxia in gasometry. The aim of our study was to examined the changes of the alveolar-arterial oxygen gradient in patients with pulmonary embolism. The survey was made in 35 patients aged from 41 to 75 with acute pulmonary embolism, of these 17 were men and 18 were women. We excluded patients with coexisting serious heart or lung disease. Pulmonary embolism was diagnosed on the grounds of presence of commonly known risk factors, sudden onset, findings on the chest radiography, hypoxia resistant to oxygen therapy, electrocardiography, echocardiography and catheterization of pulmonary artery using a Swan-Ganz catheter. The alveolar-arterial oxygen gradient was measured in arterial blood samples obtained 15 minutes after 100% oxygen ventilation, using standard formulae. All patients were administered heparin, oxygen and warfarine therapy. The control group consisted of 20 patients, 11 women and 9 men aged from 37 to 74, with deep venous thrombosis without coexisting heart or lung disease. In our study we showed that the alveolar-arterial oxygen gradient is a very useful parameter helping with diagnosis and monitoring efficacy of treatment in patients with pulmonary embolism without coexisting heart or lung diseases.