transbronchial

Transbronchial refers to procedures or sampling that are performed through the wall of a bronchus to reach lung tissue or adjacent structures. The term is most commonly encountered in bronchoscopy-based biopsy techniques used to obtain diagnostic material from the lungs or mediastinum.

The two primary transbronchial techniques are transbronchial biopsy and transbronchial needle aspiration. Transbronchial biopsy (TBB or TBLB) uses biopsy forceps passed through the bronchial wall to sample lung parenchyma adjacent to the airways. Transbronchial needle aspiration (TBNA) employs a fine needle that travels through the bronchial wall to sample mediastinal or hilar lymph nodes and masses. A newer variant, transbronchial cryobiopsy, uses a cryoprobe to detach larger tissue specimens, typically from the lung parenchyma, but with a higher risk profile for bleeding and pneumothorax.

Indications for transbronchial procedures include evaluation of interstitial or diffuse parenchymal lung disease, infectious or granulomatous processes, and cancer staging or diagnosis when mediastinal lymphadenopathy or central lesions are involved. TBNA is particularly useful for sampling mediastinal and hilar lymph nodes, while TBLB provides tissue for histopathologic assessment of parenchymal disease.

Technique and supervision: procedures are performed during bronchoscopy under local anesthesia with sedation or general anesthesia. The bronchoscope is advanced to the targeted airways, and chosen sampling devices (forceps, needle, or cryoprobe) are used to obtain specimens, which are processed for histology, cytology, and microbiology as indicated.

Safety considerations: potential complications include bleeding, pneumothorax, and infection. Bleeding is usually mild; pneumothorax risk varies with technique and lesion location. Contraindications include uncorrected coagulopathy, severe hypoxemia, or unstable cardiopulmonary status. Overall, transbronchial sampling is a valuable diagnostic tool with laboratory and clinical context guiding use.