Flexible bronchoscopy (FB) is a fundamental procedure for the diagnosis and treatment of respiratory diseases. Although midazolam is the recommended sedative agent by most guidelines, propofol has gained popularity due a short recovery time, however, evidence to propofol use for sedation during FB is scarce. There is little evidence about transcutaneous CO2 pressure (PtcCO2) behavior among patients sedated with propofol when it is administered by non-anesthesiologist and in combination with intravenous opioids for analgesia and cough inhibition.