Question

A 67-year-old man with a history of bronchogenic carcinoma presents with fever and shortness of breath. His vital signs are T 101.5ºF, HR 112 beats/minute, RR 22 breaths/minute, BP 100/60 mm Hg, and oxygen saturation 92% on room air. He has right basilar crackles on auscultation and dullness to percussion. A chest X-ray demonstrates a right lower lobar consolidation with costophrenic angle blunting. Which of the following values suggests the presence of an exudative pleural effusion?

A) Partial pressure of arterial oxygen (PaO2) < 70%
B) Pleural fluid LDH twice that of serum LDH
C) Pleural fluid pH 7.6
D) Pleural fluid:serum protein ratio < 0.5

Answer 1

A Pleural fluid LDH level that is twice that of serum LDH suggests the presence of an exudative pleural effusion, as it meets one of Light's criteria used to differentiate exudative effusions from transudative ones.

Step-by-step explanation:

The value that suggests the presence of an exudative pleural effusion in the case of a 67-year-old man with a history of bronchogenic carcinoma, fever, and shortness of breath is a Pleural fluid LDH twice that of serum LDH. Exudative effusions are characterized by higher protein and LDH levels in the pleural fluid compared to the serum. According to Light's criteria, which are used to differentiate between exudative and transudative pleural effusions, one of the criteria for an exudative effusion is a pleural fluid LDH greater than two-thirds of the upper limit of normal for serum LDH, or a pleural fluid-to-serum LDH ratio greater than 0.6. Therefore, if the pleural fluid LDH is twice that of serum LDH, this would strongly suggest an exudative effusion.

The presence of an exudative pleural effusion can be determined by checking for certain values in the pleural fluid. In this case, a pleural fluid:serum protein ratio < 0.5 suggests the presence of an exudative pleural effusion. An exudative pleural effusion is characterized by a high protein content in the pleural fluid compared to the serum.

the correct option is B) Pleural fluid LDH twice that of serum LDH