Continuoius blood sugar control during and after surgery is important to support better healing. In this study, we are investigating the safety and practicality of fully automated insulin therapy (also called "artificial pancreas") compared to standard insulin therapy during and after complex abdominal surgery in hospital. The technology mimics the function of the healthy pancreas and consists of a sensor that continuously measures blood sugar levels, an insulin pump and an application installed on a smartphone. The application receives the readings from the sensor and calculates the required insulin dosage, which then is automatically administered via the insulin pump. The result is effective blood sugar control without additional injections.