Hello, Eva. I looked on the internet and found some information. No one here on Pet Talk is a professional (though we have a couple of vet technicians), but I found some information that tells about changes that can be made at home. It's also called Chronic Bronchitis.

As for the steroids there are 'puffers' for cats. Ask your vet about them and how to use them. Maybe they would be a good choice for your cat.

When things like cough suppressants are mentioned, please ask your vet first!

Causes and symptoms of COPD
There is no definitive underlying cause for COPD in cats, but a number of different factors are thought to contribute. Repeated exposure to irritants in the air, such as cigarette smoke, pollens or other allergens may be a potential trigger of COPD. Dental disease has also been linked to COPD, as bacteria from the mouth can travel into the cat's respiratory system.


Treatment options
While COPD is ultimately irreversible once it begins, cats can still undergo treatment to improve their quality of life with this chronic disorder. Pet owners may notice that the disease flares up at certain times or seasons, and each of these incidents may require a specific treatment plan. Cats with COPD may enter severe respiratory distress, which could require oxygen therapy at a veterinary hospital. On a routine daily basis it is likely that your veterinarian may recommend medications to lessen inflammation and to dilate the bronchioles (steroids) and give the cat a bit more room for air to get through. Cough suppressants can help cats cope with the chronic coughing associated with the disease. Air filters and other environmental changes may help lessen your cat’s exposure to inhaled irritants that may trigger signs of COPD.

Pet owners will also have to address other areas of their cat's health once the animal is diagnosed with COPD. Overweight cats may have difficulty with the disease due to the lack of oxygen, so a weight loss plan might be a good idea for felines on the heavier side. Constant dental maintenance will also be important to ensure bacteria doesn't enter the lungs and cause a reaction.
Exercise is particularly important, as it helps clear the secretion present in the airways, thereby making it easier for the cat to breath. However, exercise must only be implemented gradually, as it can also cause excessive coughing. Additionally, a balanced diet will help keep the cat fit, thus improving its breathing, attitude and exercise tolerance.

Watch for excessive coughing and call your veterinarian immediately if it persists, as it may lead to a spontaneous loss of consciousness (syncope).
Non-specific treatments for COPD may include diet modification to promote weight loss in the overweight pet. Your veterinarian may prescribe supplements that have antioxidant, anti-inflammatory or immune stimulant functions as supportive treatments.
"Regular dental descaling, cleaning and polishing under general anesthesia is strongly recommended..."
It is important to maintain good oral health in the cat with COPD. Daily tooth brushing is extremely beneficial to these patients. Regular dental descaling, cleaning and polishing under general anesthesia is strongly recommended to minimize the chance that bacteria from the mouth will cause a secondary infection in the inflamed respiratory tract.
What is the success rate for treatment of COPD?

This condition is non-reversible and often is slowly progressive. Appropriate treatment will slow the progression of the disease and will relieve distressing symptoms. With proper management, most cats with COPD enjoy a normal life expectancy and an excellent quality of life. Relapses may occur when the seasons change or if air quality is poor. Adjustments to medication dosages may be necessary at these times. Consult [your vet] clinic for specific advice if this occurs with your pet.
COPD in cats is also called Asthma.

[FONT='Franklin Gothic Medium', sans-serif]In cats the steroid of choice for asthma treatment is periodic injections of the long acting steroid Depo-Medrol. Asthma in dogs and cats can never be cured, but he disease can be successfully managed, with good quality of life attained. [/FONT]
Your kitty will need medication of some kind. I hope these other ideas help. Please let us know how your kitty is doing.