Kyle Busch‘s medical emergency has been partially revealed by 911 audio obtained by TMZ Sports … with a caller saying the NASCAR superstar was struggling to breathe, overheating and coughing up blood before medics rushed to help.
During the emergency call placed around 5:30 PM Wednesday, the caller urgently requests an ambulance to a training facility in Concord, North Carolina … telling dispatch, “I’ve got an individual that’s shortness of breath, very hot, thinks he’s going to pass out, and he’s producing a little bit of blood, coughing up some blood.”
The caller also confirmed the patient was still conscious at the time … repeatedly telling dispatch, “He is awake. He’s awake. He’s awake.”
Kyle was known to use this testing facility extensively since joining Richard Childress Racing — and according to the audio, he was lying on a bathroom floor inside the complex while employees prepared for paramedics to arrive.
The caller even asked responding crews to shut off their sirens when approaching the building … while explaining he would wait outside and flag them down at a side entrance.
TMZ also obtained dispatch audio from the incident … listen to it above.
As we reported … Busch reportedly became unresponsive Wednesday while testing in a Chevrolet racing simulator … just one day before his death at 41.
He was transported to a Charlotte-area hospital after collapsing during the simulator session … though officials have not yet confirmed his exact cause of death.
The shocking collapse came less than two weeks after Busch reportedly requested medical assistance during a race weekend at Watkins Glen, where he had been dealing with what was described as a severe sinus-related illness.

January 2018
Busch’s death sent shockwaves through the racing world Thursday … with tributes pouring in from NASCAR drivers, teams and fans mourning one of the sport’s most dominant modern stars.
The two-time Cup Series champion leaves behind a massive legacy in motorsports … including hundreds of victories across NASCAR’s top national divisions.