Comparison of Manual and Suction Pump Aspiration Techniques for Performing Bronchoalveolar Lavage in 18 Dogs with Respiratory Tract Disease

Background Different aspiration techniques to retrieve bronchoalveolar lavage fluid ( BALF ) affect sample quality in healthy dogs. Studies evaluating these techniques in dogs with respiratory disease are lacking. Objectives To compare sample quality of BALF acquired by manual aspiration ( MA ) and suction pump aspiration ( SPA ). Animals Eighteen client‐owned dogs with respiratory disease. Methods Randomized, blinded prospective clinical trial. Manual aspiration was performed with a 35‐mL syringe attached directly to the bronchoscope biopsy channel and SPA was performed with a maximum of 50 mmHg negative pressure applied to the bronchoscope suction valve using the suction trap connection. Both aspiration techniques were performed in each dog on contralateral lung lobes, utilizing 2 mL/kg lavage volumes per site. Samples of BALF were analyzed by percentage of retrieved infusate, total nucleated cell count ( TNCC ), differential cell count, semiquantitative assessment of slide quality, and diagnosis score. Data were compared by paired Student's t ‐test, Wilcoxon signed‐rank test, chi‐squared test, and ANOVA. Cohen's kappa coefficient was used to assess agreement. Results The percentage of retrieved BALF ( P  =   .001) was significantly higher for SPA than MA . Substantial agreement was found between cytologic classification of BALF obtained with MA and SPA (kappa = 0.615). There was no significant difference in rate of definitive diagnosis achieved with cytologic assessment between techniques ( P  =   .78). Conclusions and Clinical Importance Suction pump aspiration, compared to MA , improved BALF retrieval, but did not significantly affect the rate of diagnostic success of bronchoalveolar lavage ( BAL ) in dogs with pulmonary disease.