Her daughter Melissa said she remained hopeful of a recovery as medics slowly wake her up – a process which will take until Tuesday. Even then there are fears that she could be left with permanent brain damage or in a wheelchair.
Melissa has been keeping a vigil since the 81-year-old stopped breathing during surgery to her vocal chords at a Manhattan clinic on Thursday.
The pair star together on a reality TV show called Joan & Melissa: Joan knows best? Comedienne Joan has continued working tirelessly into her ninth decade, also hosting Fashion Police on E! along with Giuliana Rancic and Kelly Osbourne.
In recent days they've both tweeted their support for her. "Praying for @Joan_Rivers and @MelRivers. Even though Joan's the strongest woman I know, every single prayer counts. I love you, Joan," posted Giuliana.
Meanwhile, Kelly urged fans to keep the star in their thoughts, saying: "4 the first time in years I got down on my knees & prayed tonight! I encourage U 2 do the same 4 @Joan_Rivers my grandma! #inconsolable,"
The star had shown no signs of illness days prior to her operation, recording scenes for Fashion Police as scheduled and performing gigs as part of her current North American tour.