The Keeping Up With The Kardashians star spoke to America's Today show about the phone call she received on 13 October telling her Lamar was in a coma.
She recalled: "They told me they had four hours. It's a horrible call to get. Getting to the hospital and knowing he's a coma and having to run tests and make medical decisions, it's terrifying.
"You have to make risk and reward decisions like, 'There is an 80 per cent chance if we do this operation he might pass away, but if we don't, there is a 90 per cent chance he will.' Just having to make these executive decisions is really hard on anybody. It was probably one of the most emotionally stressful times of my life."
Khloe and Lamar were married from 2009 until 2013 but as their divorce had not been finalised at the time of his collapse, she was legally still his wife and therefore in charge of medical decisions.
She was by Lamar's bedside every day while he was hospitalised in Las Vegas. Now, he's been transferred to a hospital in Los Angeles to continue his recovery.
Khloe said: "He is learning how to walk again and cognitive therapy and speech therapy. They think within a year and a half to two years, mentally, he might be fully recovered, but they don't now."