Rest PETCO2 As a Predictor of Post-operative Complications

Measurements will take place day before surgery, under resting conditions (while sitting in a quiet room with no disruptions) using the Capnography monitor from Nonin Medical (breath by breath data will be recorded and analyzed). Patients will be allowed to get used to the nasal cannula for the first two minutes. Mean end-tidal CO2 value will then be calculated from the following two minutes of spontaneous breathing.