A lateral thoracotomy approach for thoracic duct cannulation and lymphatic fluid collection in a feline model

This study describes a lateral thoracotomy approach for thoracic duct cannulation and lymphatic fluid collection in a feline model. The thoracic duct was cannulated via a left lateral intercostal thoracotomy in 12 cats. Lymphatic fluid was collected for up to 16 days and analyzed on days 3, 9 and 16. The volume collected and duration of cannula patency were recorded. Contrast imaging of the thoracic duct was performed if fluid ceased to flow or at the end of the 16-day study period. In two cats, the cannula became dislodged within 24 h. For the remaining 10 cats, mean daily volume collected was 43.7 mL (median 41.0, range 2.3 to 152.4 mL), and mean duration of cannula patency was 8.2 days (median 6.5, range 3 to 16 days). Contrast imaging revealed that the cannula was patent in three cats, obstructed in two cats, and the thoracic duct had ruptured or had extravasation of contrast outside the duct in five cats. Cytological examination of lymphatic fluid from the three time points revealed normal appearing small lymphocytes (97%) and few (3%) non-degenerate neutrophils, macrophages, eosinophils, and plasma cells. Based on the results of this study, lateral thoracotomy approach for thoracic duct cannulation is a feasible technique for collecting lymphatic fluid in cats. This technique may have application as a model for short-term evaluation of thoracic fluid in cats; however, cannula patency was unpredictable and should be considered when utilizing this technique.