During the autopsy, doctors discovered that Michael Jackson had diminished lung function due to chronic lung inflammation and a condition called respiratory bronchiolitis, a lung disease commonly seen in smokers. Why is this important to his death, when it wasn't the cause?
Propofol is an anesthetic and sedative, and those qualities have an impact on our lungs and heart -- its sedative properties reduce lung function. The benzodiazepines found in his blood at the time of his death also have a sedative effect.
While the autopsy report is clear that Jackson's impaired lung function didn't cause his death, it would have put him at a greater risk of respiratory and cardiac-related complications while under sedation.