Table 1 Inclusion and exclusion criteria for the PROVAR trial

Patients scheduled for elective open abdominal surgery with expected duration >3 h

Chronic lung disease, except COPD GOLD stage I and II and untreated bronchial asthma

ASA class 2 and 3

Body mass index >40

Expected extubation in the OR

Hypersensitivity or allergy against one of the drugs administered during the study or against drugs with similar chemical structure

Informed consent to participate in the study signed by the patient

Participation of the patient in another clinical trial within the last 4 weeks

History of substance abuse or any other mental status possibly affecting informed consent

Pregnancy or breastfeeding

Women in an age range of possible pregnancy if not:

• Postmenopausal (12 months of amenorrhea or 6 months of amenorrheawith serum FSH >40 lU/ml)

• Postoperative (6 weeks after bilateral ovariectomy with or without hysterectomy)

• Regular and correct use of contraceptives with failure rate of <1% per year

• Sexual inactivity

• Vasectomy of sexual partner

Suspected low patient compliance

Contraindication for MRI exams

Mechanical ventilation within the last 30 days