One thing you might want to try is manipulation of her diet. Chyle is created by the absorbtion of long chain fatty acids. If it can't be reabsorbed, it leads to chylothorax. (this can happen if there is a problem with the thoracic duct by tumor or trauma, or if the pressure in the central veins is too high so the duct can't dump the fluids back into the circulation).
If there is dog food available that is made with medium chain tryglycerides, you could try that. Another alternative is to feed low fat food and supplement her diet with MCT oil.
She is also losing lots of protein with the chyle that is being drained, so I'd recccomend making sure she gets plenty of protein.
Good luck.
Jake's mom
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