An Intensive Care Unit (or ICU) was an area in a hospital where patients with severe medical conditions were treated.
In 2011, Geraint Cooper suffered two heart attacks only to be taken out of intensive care as a result of Miracle Day. (TV: The New World)
The Miracle Day phenomenon caused overcrowding as people with fatal conditions no longer died. Hospitals began to look at old abandoned hospitals to handle the overflow of ICU patients. Ultimately, overflow camps were established to hold the increasing numbers of ICU patients. (TV: Escape to LA)