DMK President M Karunanidhi has undergone Tracheostomy to optimise breathing. He is being treated now, and is stable, says a release from Kauvery Hospital. Karunanidhi was admitted to Kauvery hospital in Chennai late last night after he complained of difficulty in breathing. The hospital said Karunanidhi was readmitted with breathing difficulty due to throat and lung infection. In a tracheostomy, an incision in the windpipe is made to relieve an obstruction to breathing.