7:05 PM PT -- Sources tell us Khloe and Kim Kardashian ... as well as Kris Jenner are heading to Las Vegas shortly to meet Lamar at the hospital.Lamar Odom is fighting for his life after falling into unconsciousness at Dennis Hof's Love Ranch South in Pahrump, Nevada ... TMZ Sports has learned.
Sources at the Love Ranch tell us ... 35-year-old Odom arrived at the Ranch Saturday and was partying with the girls for days. A source at the Ranch said Lamar was taking an herbal substitute for Viagra.
We spoke with Hof ... who tells us Tuesday afternoon, a woman went into Odom's room in the VIP suites and found him unconscious.
We're told the woman began screaming for the manager -- who called 911.
The manager rolled Lamar over on his side and saw "mucus-type liquid coming out of his nose and mouth."
An ambulance took Lamar to Pahrump hospital, where doctors intubated him ... an indication he could not breathe on his own.
We're told Lamar is being airlifted from the hospital to Las Vegas for more treatment.
Our sources tell us, "It's not good."
We're told Lamar had been partying at the ranch by himself -- with no friends or entourage -- and is now alone at the hospital.
The ranch staff says they want to be in the room with Lamar but since they're not family they're not allowed.
Story developing ...