Cardiac or pulmonary dyspnea in patients admitted to the emergency department

A simple and quick way of discrimination between cardiac and pulmonary causes of dyspnea is essential in patients admitted to the emergency department. We aimed to assess the utility of easily applicable diagnostic tools in the differential diagnosis of cardiac and pulmonary causes of dyspnea in patients presenting with shortness of breath. Clinical and radiologic evaluation, peak expiratory flow (PEF), PaO2, PaCO2 measurements were performed in 94 patients admitted to the emergency room with dyspnea. All the patients were hospitalized for accurate diagnosis and later were categorized into cardiac and pulmonary dyspnea groups. PEF, %PEF (percent of predicted PEF), dyspnea differentiation index (DDI = PEF x PaO2/1000), %DDI (%PEF x PaO2/1000), PaO2 and PaCO2 measurements were compared between the two groups. When cardiac and pulmonary dyspnea groups were compared, considering 1.6 as the cut-off value for DDI, measurements above this value imply cardiac pathology with 76.7% sensitivity and 67.2% specificity. The sensitivity and specificity for cardiac dyspnea calculated according to the cut-off values were 96.7% and 40.6% for %DDI; 86.7% and 60.9% for PEF; 86.7% and 54.7% for %PEF; 66.7 and 68.7 for PaO2. Also for pulmonary dyspnea, sensitivity and specificity values for PaCO2 were 50% and 93%. We conclude that DDI, %DDI, PEF, %PEF, PaO2 and PaCO2 are simple and easily applicable tools for differential diagnosis of cardiac and pulmonary dyspnea. Adjunctive utility of these tests in the emergency department with clinical and radiologic evaluation contributes to this discrimination.