(CNN) -- It sounds like a bizarre episode of the 90s comedy-drama "Doogie Howser, M.D."
But this is reality. And this teen wasn't a board-certified surgeon, but, according to police, merely someone who, through a clerical error, acquired a medical badge and spent several days posing as a doctor's assistant and treating patients.
Opening statements in the trial of 18-year-old Matthew Scheidt is scheduled to start Tuesday in a Florida courtroom.
Scheidt faces two counts of impersonating a physician's assistant and four counts of practicing medicine without a license for the days he spent at Osceola Regional Medical Center in August 2011.
He was 17 at the time.
After his arrest, Scheidt admitted to performing CPR on a patient suffering from a drug overdose, authorities told CNN affiliate WFTV.
"I felt so uncomfortable even doing that. And, you know, the only reason why I did do it was because there was nobody else in there. And I'm not going to let her die," Scheidt told investigators at the time, according to the television station.
Scheidt told investigators he went to the hospital last year to get a badge for his job as a clerk at a doctor's office across the street. But someone botched the paperwork.
"Their error was putting me in apparently as a physician assistant into their computer," Scheidt told investigators. "Let's even say that I said I was a physician assistant. Let's even say that I was. Are you that stupid that you are just going to put me in the system as that, without any credentials or any paperwork or nothing?"
Prosecutors allege that Scheidt used the badge to work in the hospital for weeks in the emergency room, changing bandages, handling IVs and helping to conduct exams.
During his interrogation, Scheidt confessed and admitted he had made mistakes, according to WFTV.
"I messed up. I should have addressed the issue when it was given to me. I just didn't want any questions asked, like I just wanted to learn as much as I possibly could," he said.
Osceola County Circuit Court Judge Jon Morgan said Monday he expects the trial to last three days.
Scheidt has pleaded not guilty to the charges and has sought to get his confession thrown out of court.
He was arrested in September 2011 and allowed to bond out.
But in January, he was back in police custody.
The charge: impersonating a police officer.