In this video, Dr. K K Aggarwal, President Heart Care Foundation of India and Group Editor in Chief MEDtalks, will discuss the levels at which oxygen is started. He says that this question is asked by nurses or junior doctors whether each patient has to be started oxygen when admitted in the hospital. The indication for oxygen is when the SPO2 level is less than 88%. SPO2 level is abnormal if it is less than 95%.