my wife 62 of age every six months get this bad cough coming, she tried all the cough mixtures but they doesn't work at all ,day time the cough will come , almost every day every 1-2 hours, she will cough non stop,night time too disturb her sleep. she had her by pass done in2005, is her lungs infected by this due to the operation,please help doc what can be done to stop it ,thank you