What Causes Lack Of Consciousness?

hello sir my mother was admitted in a riayd hospital before 26 days . she diagnosed as bi lateral pnemonia doctors and the doctors immediately shifted her to icu unit and the doctor said she taking oxygen in but not releasing pco safter 4 days she was quiet better but from 13-5 -2010 she is in semi unconscious but doctors were saying she is in coma is unresponsiveness is coma or i came to know that unresponsiveness is not always coma plz help me sir i am also an hyderabadi based in riyad