After randomization, the subjects undergo flexible bronchoscopy either with fractionated propofol administration or with propofol-TCI. Measurement of blood pressure, heart rate, oxygen saturation, and oxygen requirement are measured continuously during the procedure and thereafter. Cumulative propofol dose, and induction, procedure, and recovery time are noted continuously during and after the procedure.

In daily clinical praxis, propofol sedation is given manually in repeated doses (fractionated) by a specially-trained nurse in attendance of the bronchoscopist. But, fractionated propofol administration (FPA) may lead to oversedation and enhanced side effects (oxygen desaturation and arterial hypotension), as a stable plasma concentration of propofol is not maintainable. In contrast to FPA, continuous infusions of propofol are commonly used to induce and maintain long-term sedation in intensive care units and general anesthesia. Recently, continuous propofol infusion for sedation in bronchoscopy has been shown comparable to FPA in terms of safety and efficacy. Generally, infusion devices can be manually controlled (MCI) or target-controlled (TCI). In the latter, the physician sets a target blood concentration and the computerized infusion device makes the necessary changes to the infusion rate.

The objective of this study is to compare propofol TCI with FPA in flexible bronchoscopy concerning patient safety and sedation quality.

Inclusion Criteria:

• Subjects undergoing a planned, ambulatory flexible bronchoscopy (for transbronchial lung biopsy or endobronchial ultrasound guided procedures) in moderate sedation, aged between 18 and 85 years

Exclusion Criteria:

• History of solid organ or bone marrow transplantation with the use of an immunosuppressive therapy
• HIV infection on anti-retroviral therapy
• Alcohol consumption more than two standard drinks per day
• Use of illicit drugs (heroin, opiates)
• Any contraindication to use propofol for sedation (e.g. allergy)
• Body mass index > 35 kg/m2
• Mental disorder preventing appropriate judgment concerning study participation
• Missing written patient's informed consent