Audio from the 911 call reveals the nurse by Lilo's side was seriously worried about the 25-year-old's medical condition.
"It's serious. A code three," the nurse is heard saying to the 911 operator.
According to TMZ, "code three" is "lingo for life-threatening response."
Seven paramedics were sent to the "unresponsive" actress's penthouse suite after the call was made, but left without taking her to hospital.
Lilo joked about the incident a few days later.
"Note to self … After working 85 hours in four days, and being up all night shooting, be very aware that you might pass out from exhaustion and seven paramedics might show up at your door … Hopefully they're cute. Otherwise it would be a real let down," she wrote on Twitter.
Her rep, Steve Honig, supported the star's claims, saying she was "extremely exhausted and slightly dehydrated".
Fans could have even more cause for concern, after a source told Us Magazine that Lilo has been smoking two packs of cigarettes a day on the set of her new telemovie about Elizabeth Taylor, Liz and Dick.
"Literally every time she finishes a scene she lights up another cigarette,” the source said.
"You can hear the crew saying, 'That's cut — get a cigarette for Lindsay'."
"Lindsay has been working hard, but without the nicotine she probably could not make it through as she appears stressed at times and they do seem to calm her down."