This study aims at determining whether diaphragm ultrasound examining diaphragm thickening fraction, excursion and density before and after surgery can predict respiratory complications in the postoperative period. Patients scheduled for major elective abdominal, pelvic or vascular surgery will be included in the study and diaphragm ultrasound is performed before surgery and after surgery in the postoperative ward. Physiological parameters, laboratory parameters, data on surgery and anesthesia and comorbidities will be registered. Complications such as pneumonia, desaturation, need for intubation and other respiratory events up to 30 days will be registered and later correlated with the diaphragm measurements.