Evaluation of a technique and diagnostic value of bronchoalveolar lavage carried out with a flexible catheter

Twenty-six horses of various breeds aged between 4 and 19 years were included into this study. All horses underwent a clinical examination of the respiratory tract, endoscopic examination and cytologic examination of tracheal aspirates and bronchoalveolar lavage fluid (BALF). Bronchoalveolar lavage was performed by a blind technique using a silicon catheter of a length of 240 cm [Broncho-Alveolar Lavage (B.A.L.) Catheter; Cook, Sursee, CH). After sedation with xylazine and methadone and local anaesthesia of the trachea and bronchi 250 mi 0.9% sterile NaCl solution were instilled and aspirated. During introduction of the catheter into the ventral meatus 24 horses showed no signs of resistance, 4 horses mild and one 1 horse severely resisted introduction of the catheter. Further advancement of the catheter induced mild coughing in 17 horses and severe coughing in 2 horses. In 28 of 30 performed lavages fluid could be recovered (x+/-s=123.5+/-33.46 mi). The catheter was found 1 2 times in the left lung and 15 times in the right lung. On radiographs the lip of the catheter was identified above the base of the heart in 2 horses and between the 8(th) and the 13(th) intercostal space in 24 horses. Comparison of tracheal aspirates and BALF was possible in 24 cases. In 10 cases complete agreement between cytology of tracheal secretions a nd BALF was present. Disagreement on diagnosis was based on severity of disease in horses with COPD (n=15) a nd horses with acute or subacute bronchiolitis (n=3). In conclusion, the BAL technique described in this study is well tolerated by horses and easy to perform with a low amount of technical equipment. The method is suitable for use in equine practice and gives good cytologic results when the BALF samples are processed within 24 hours.