Capillary Versus Suction Needle Aspiration for Endobronchial Ultrasound (EBUS) Biopsies.

Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration is a procedure used to obtain tissue samples (biopsies) of lymph nodes near the airways or of lung tumours growing in close proximity to the airways. Briefly, an endoscope with an ultrasound probe which is inserted through the mouth and into the airways. Once in the airways, the ultrasound allows for identification of the optimal biopsy site; a hollow biopsy needle is then inserted into the tissue under real-time ultrasound visualization and a sample is extracted.

In the investigator's centre, the extracted sample is then immediately subjected to rapid on-site evaluation (ROSE). During the ROSE procedure, a cytotechnologist uses part of the sample to make a limited number direct smears which are then rapidly stained and evaluated under a microscope by the cytotechnologist. The cytotechnologist provides an assessment of the adequacy of the sample for diagnosis. The respirologist performing the EBUS then uses this information to: i) determine whether additional sampling is required, and ii) triage any additional samples for ancillary studies as needed. A final cytopathological diagnosis is established several days later, when all of the material from the procedure (including the material not evaluated at ROSE) is examined by a cytopathologist.

There are different techniques which are utilized to perform the needle aspiration biopsy. Suction aspiration (where pressure suction is applied to the needle to draw out material) which is the standard at many centres around the world and capilliary suction (where a tiny wire is drawn back slowly to create more gentle suction force) which is utilized often at LHSC.

The purpose of this study is to evaluate for differences in ROSE adequacy between these two methods.