The 35-year-old former basketball star was found unresponsive after spending several days at the Love Ranch in Crystal, Nevada.
Lamar Odom was found unconscious in a room at the Love Ranch, a legal brothel, in Pahrump, Nevada, the Nye County Sheriff Sharon A. Wehrly confirms to ET.
At approximately 3:15 p.m. on Tuesday, a call was placed by Richard Hunter, Media Director for Dennis Hof's Bunny Ranch, requesting an ambulance for an unresponsive male, identified as Odom, in a medical emergency at the Love Ranch in Crystal, Nevada, located about 20 miles north of Pahrump, Nevada.
Odom was transported less than 20 minutes later to Desert View Hospital, where he arrived at 4:15 p.m. Though arrangements were made to have Odom transported by helicopter, it was determined that he "was unable to be transported by air due to his stature," and instead, was moved to Sunrise Hospital in Las Vegas.
The 35-year-old former basketball star, and ex of Khloe Kardashian, arrived by himself at the Love Ranch late Saturday night, Love Ranch owner Dennis Hof told ET, and "was in a great mood." According to TMZ, which first broke the news, Odom spent several days partying with a number of different girls at the establishment.
Hof said that Odom was last seen by two of the girls at 6 a.m. Tuesday morning, and was found unresponsive in his room by one of them this afternoon, who then alerted management. When the 911 operator advised the person to roll Odom on his side, fluid was seen streaming out of his mouth, according to TMZ.
Hof told ET that Odom had been ingesting "a lot of herbal Viagra," used for sexual enhancement.
WATCH: Khloe Kardashian Admits She Regularly Checks Up on Ex Lamar Odom
Odom reportedly required intubation, a procedure often performed by doctors to maintain an open airway into the lungs when a patient cannot breathe on their own.
According to People, Odom's ex Khloe Kardashian has been apprised of his medical condition, which has reportedly been described as "serious." She is expected to fly out to Nevada to be by Odom's side in the hospital, and may possibly be joined by her sister Kim Kardashian.
WATCH: Kim Kardashian Says She Feels 'Sick to Her Stomach' When Khloe Talks to Ex Lamar Odom
In a recent episode of Keeping Up With the Kardashians, Odom's ex Khloe Kardashian admitted that she frequently checks up on Odom to "make sure that he's OK."
Odom and Kardashian signed and filed final divorce papers in July after getting married in 2009. In 2011, the couple appeared in their own reality series, Khloe & Lamar, that lasted for two seasons on E!.
In August 2013, Odom was arrested on charges of driving under the influence of alcohol. Odom plead no contest and was given three years' probation and ordered to complete an alcohol abuse treatment program. Odom has also been at the center of speculation that he's battled substance abuse issues in the past.
WATCH: Khloe Kardashian Reaches Out to Sisters Amid Lamar Odom Drama
It has been a tough year for Odom who lost two close friends in June. Odom's friend Jamie Sangouthai died, reportedly from complications related to drug use, just days before his friend Bobby Heyward passed away as well.
ET has reached out to local law enforcement officials and will continue to cover this breaking story as it develops.
WATCH: Khloe Kardashian Says She Misses Lamar Odom 'Every Day'