Please consult with your Dr. for personal medical advice and/or an RD who knows your health history and any particular medications you may be taking. Many drugs, including bronchodilators, expectorants, and corticosteroids, may have food-drug implications.
In general, avoid gas-producing foods, such as cabbage, beans, cauliflower, broccoli, etc, to prevent the stomach from pushing on the diaphragm. Also avoid carbonated beverages (not allowed in the NutriBullet anyway).
Fluid restriction may be necessary depending on severity so consult your Dr. first.