A Randomized Controlled Trial to Compare Procedural Yield of Bronchoalveolar Lavage Using Three Different Techniques in Subjects Undergoing Flexible Bronchoscopy

Bronchoalveolar lavage (BAL) via flexible bronchoscopy is a method used to sample the cellular and microbiological components of the alveolar space. It is a procedure in which 2-3 measured aliquots of sterile normal saline are instilled after wedging the scope to the suitable segmental bronchus. BAL is performed from the segments/ lobes showing ground-glass opacities (GGO), tree-in-bud lesions or focal consolidations guided by HRCT. In diffuse lung involvement, BAL is performed either from RML or the lingula.[3] It is recovered through the bronchoscope via different suction methods so as to get a sample of epithelial lining fluid of small airways and alveoli. Either manual suction or wall suction can be used for aspiration of fluid during BAL. The fluid recovered is then sent for cytology and microbiology examination studies including AFB, MGIT, GeneXpert, Galactomannan, fungal cultures to diagnose various conditions like PAP, eosinophilic pneumonia, bacterial or fungal infections, specific forms of ILD Normal BAL cellular components are specified as: Alveolar macrophages (AM) 85%, Lymphocytes 5-15%, Neutrophils <= 3%, eosinophils <1%. The presence of squamous epithelial cells indicates contamination by oropharyngeal secretions. [4] Additionally, BAL can be a tool for pulmonary toilet in rare diseases such as pulmonary alveolar proteinosis by helping to remove the abnormal surfactant material that accumulates with this disease.

Manual suction: It can be done using the same syringe used for instillation of the normal saline. At least 100 ml normal saline should be instilled while performing BAL and should not exceed 200 ml.

According to the studies, Modification of the manual suctioning technique (by connecting small tubing attached to syringe) provides higher percentage of BAL fluid [5].

Wall suction: During suctioning the instilled fluid, negative pressure is applied using continuous wall suction. The pressure should be <100mmHg or should be adjusted to prevent airway collapse.[6] In a study conducted by Aruna D. Herath[7], 73 pediatric patients were enrolled for a RCT undergoing flexible bronchoscopy and BAL. Two different suctioning techniques were compared for % of BAL fluid recovery. Sterile normal saline according to 1ml/kg was instilled and 100-150mmHg of negative pressure was applied for wall suction method. Thus it concluded that wall suction had better BAL fluid recovery than handheld syringe suction. Diagnostic yield was the same for both techniques.

Luis M. Seijo[8], conducted a prospective randomized study of total 220 patients undergoing BAL. Study comparing manual and wall suction in performance of BAL resulted that manual aspiration is superior to wall suction yielding larger quantity of BAL. Additionally, extra tubing with 50 ml syringe was added in manual suction technique and 50mmHg negative pressure was used in wall suction method.