In accordance with the principles of GCP, monitoring of the study will be arranged by the Sponsor. UCR has been appointed by the Sponsor to monitor this study. During the study, the Monitor will have regular contacts with the study sites, including visits to ensure that the study is conducted and documented properly in compliance with the protocol, GCP and applicable regulatory requirements. The Monitoring activities will be made in accordance with the SOP at UCR. Both centralized monitoring activities and on-site monitoring activities will be used in this project. It has been decided that the major part of the monitoring will be made by centralized methods together with continuous telephone contacts with site but with limited on-site activities. This decision is based on the nature of the study - observational with no other study specific procedures than the randomization. Additionally, the investigational products used are well established within clinical practice since many years and with documented safety profile. Each site will have a site initiation (can be organized as multi-center initiation meeting or web-based training) with focus on providing information about study objectives, study procedures and eCRF-training. Each site will then have at least one on-site visit during the study. Based on the outcome of centralized monitoring activities, the frequency of on-site monitoring activities may be increased. The Monitor will review source documents for verification of consistency with the data recorded in the eCRFs for a random sample of pts. In addition, selected key variables will be proofread. All inconsistencies detected during these procedures will be resolved through the DCF's, being issued to the monitor or investigational site personnel. Completed DCFs will be filed and entered into the database accordingly. The Monitor will also provide information and support to the Investigators. The centralized monitoring will be used to detect each site´s level of compliance in terms of completion of eCRF generally but also with focus on critical data (e.g. compliance in randomization to propofol or sevoflurane and date of surgery). The outcome of the statistical checks that will be used will indicate whether increased monitoring activities are needed on a specific site. In terms of review of completed informed consent, only a random sample of the pts will be checked by the monitor in connection with on-site visit. Site will log all completed informed consents on on-going basis. This log needs to be distributed to the monitor on on-going basis and this will serve as monitoring tool of the consent-process. If there are signs of that the site does not comply with the specified consent-process, extended site-specific training/ increased monitoring activities will be needed. All monitoring procedures, including both centralized methods and on-site activities, will be described in the Monitoring Plan which will be compiled in collaboration with the Sponsor. The study center may also be subject to quality assurance audit by the Sponsor as well as inspection by the Medical Procurement Agency. The Investigator and other responsible personnel must be available during the monitoring visits, audits and inspections and should devote sufficient time to these processes.