Performance Characteristics and Technical Outcomes of Single-use vs. Reusable Gastroscopes Evaluated in the OR

The goal of this clinical trial is to investigate whether single-use gastroscopes are as good as reusable gastroscopes when used in the operation theater in all patients where gastroscopy in the operation theater is indicated. The main question it aims to answer is: \- Is the technical success and performance characteristics the same for single-use and reusable gastroscopies? Researchers will compare single-use gastroscopes with reusable gastroscopes to see if the technical success and performance characteristics are the same in the to groups. Participants will in the first period have gastroscopy with a single-use gastroscope. In the second period participants will have gastroscopy with a reusable gastroscope.