Often, the immobility after a surgery can cause problems with the lungs. One of the goals of post operative care is to make sure deep breathing and coughing is done, as well as getting up and about as soon as possible following surgery. If not, the lungs sometimes don't expand enough and pneumonia or a build up of mucus can occur. A mucus plug means that mucus has built up and has blocked a portion of the lung, not allowing adequate air exchange.
Usually breathing treatments, such as inhaled medicine, or postural drainage. Postural drainage is done by a respiratory therapist and is a pummeling method done to loosen things up so they can be coughed up. In some cases, when infection is involved, antibiotics may be of help.