hi my son is 41/2 years old. he got respiratory infection at 5th month. he undergone ventillation for 3 days and as in patient for 10 days. after that treatment was continued with duoline and budecart for 6 months in the form nebulization. later spacer was given adn continued for 3 months. after that he is getting cold adn cough at every 2 or 3months. now he is suffering with cold and cough, treating with duoline adn budecart with nebulisation. how to overcome this problem permanently.