Randomized controlled trial to determine the efficacy of different needles sizes (22G and 21G) used in endobronchial ultrasound guided transbronchial needle aspiration

Among the bronchoscopic techniques in diagnosis of sarcoidosis, transbronchial needle aspiration (TBNA) of lymph nodes has emerged as a particularly useful supplement to the previously known endobronchial and transbronchial biopsies. The efficacy and safety of conventional TBNA is well established. With improvements in technology, the last decade has seen the use of convex probe endobronchial ultrasonography (EBUS) to guide TBNA under direct vision. This technique is a minimally invasive alternative to mediastinoscopy, further it offers additional advantage of choosing the appropriate node for sampling on the basis of their echogenicity. Studies subsequently have demonstrated the superiority of EBUS TBNA over conventional TBNA.

Once the role of TBNA in diagnostic bronchoscopy was established, technical aspects of the procedure became the topic of research. Needle size used in TBNA is one such important factor. Apparently, larger the needle, better the tissue yield and hence improved diagnostic capability. Conventional TBNA is usually performed with a 19G needle, though varying sizes have been used in different studies (18, 21, 22, 26G). On the other hand, EBUS-TBNA is performed with a 22G needle. More recently 21G needles are being used for the same purpose. There have been conflicting reports in literature, when these two needle sizes have been compared with regards to the adequacy of the sample, accuracy of diagnosis and the rate of complications. Moreover, the above studies undertaken so far were done from centers where malignancy was the predominant diagnosis. Whether the needle size used during EBUS TBNA has any impact on diagnosing benign diseases like sarcoidosis is still not clear, hence this study was planned. The investigators hypothesize that performing EBUS-TBNA using 21G needles may enable identification of intact compact granulomas in sarcoidosis, and hence a better diagnostic yield than using a 22G needle.

Inclusion Criteria:

• Age ≥18 years
• Clinicoradiological suspicion of sarcoidosis where endobronchial ultrasound guided transbronchial needle aspiration is contemplated
• Enlarged hilar and mediastinal lymph nodes >10 mm (any axis) on computed tomography of the chest

Exclusion Criteria:

• Hypoxemia (SpO2 <92%) on inspired fraction of oxygen 0.3
• Treatment with systemic glucocorticoids for more than 2 weeks in the preceding three months
• Diagnosis of sarcoidosis possible with another minimally invasive technique such as skin biopsy or peripheral lymph node biopsy
• Failure to provide informed consent