Standardization of Bronchoalveolar Lavage Aspiration Techniques to Optimize Diagnostic Yield of Canine Lower Respiratory Tract Samples

Bronchoalveolar lavage (BAL) is a minimally invasive technique utilized in human and veterinary medicine to sample the lower generation bronchi and alveolar spaces. The basic technique for BAL involves infusion of sterile saline into the lower airways and re-aspiration of the fluid (bronchoalveolar lavage fluid; BALF). Certain aspects of BAL technique and BALF processing affect sample quality, and sample quality is important to ensure meaningful cytology. Aspiration techniques for retrieval of BALF have not been critically evaluated in companion animal medicine. This research project compared three aspiration techniques for retrieval of BALF in dogs [manual aspiration without tubing (MA), manual aspiration through polyethylene tubing (MAPT) and suction pump aspiration (SPA)] and their effect on sample quality in healthy dogs and dogs with respiratory tract disease. SPA consistently retrieved a higher proportion of BALF than MA and MAPT. In addition, SPA yielded improved sample quality compared to MA and MAPT. The improved BALF retrieval and cellularity scores in SPA samples did not significantly increase the diagnostic rate achieved from BALF cytology in dogs with pulmonary disease. The results indicated that both MA and SPA are suitable for BAL in dogs with respiratory tract disease. Yet, for the purpose of creating a standardized BAL technique in dogs, SPA is recommended for BALF retrieval due to the improved sample quality parameters.