The most appropriate next step in management is bronchoscopy. Bronchoscopy is generally indicated for evaluation of new respiratory symptoms that may be associated with airway pathology (for example, hemoptysis or stridor). This patient presents with massive hemoptysis, which is generally defined as expectoration of at least 100 mL of blood (one-half U.S. cup equals approximately 120 mL). Chest imaging in this patient showed no evidence of pulmonary embolism but did show ground-glass opacification in the right lower lobe. Although this could represent a source of infection, it more likely represents aspirated blood in this patient without symptoms of an infection. Because of this patient's extensive smoking history, he is at increased risk of lung cancer, which may present as an endobronchial lesion causing hemoptysis. Therefore, he should undergo bronchoscopy with airway inspection to evaluate for an endobronchial lesion; a bronchial wash can also be sent for cytologic and microbiologic studies. Even if there is no endobronchial lesion, bronchoscopy could confirm the source of bleeding if blood is seen originating from the right lower lobe.

Although respiratory infections can lead to hemoptysis, this patient has no symptoms or laboratory studies suggesting an infection such as community-acquired pneumonia or an exacerbation of his COPD, for which antibiotic therapy might be indicated. It is also unusual for pulmonary parenchymal infections to cause massive hemoptysis. Therefore, antibiotic treatment would not be indicated in this patient.

High-resolution CT is used to evaluate the pulmonary parenchyma in greater detail than standard-protocol chest CT and is the study of choice for evaluating disorders such as interstitial lung disease. However, it would not adequately define endobronchial lesions as a possible cause of hemoptysis and would therefore not be an appropriate next study in this patient.

Some patients may have difficulty distinguishing between hemoptysis and hematemesis, making the history a key component of evaluation to identify the likely source of bleeding. In patients in whom a gastrointestinal cause is suspected, upper endoscopy would be appropriate for further evaluation. However, this patient's presentation is consistent with a pulmonary source of bleeding, and upper endoscopy would not be appropriate before excluding hemoptysis.