The body core temperature drops during general anesthesia. To maintain homeostasis, patients require warming measures. Different methods to measure body core temperature exist, which are either highly accurate but invasive, or non-invasive but non-accurate. A new monitoring device, Tcore(TM), enables a non-invasive but accurate core temperature assessment.

This study is performed to quantify accuracy and bias of the Tcore system in comparison with the blood temperature, which is the gold standard of core temperature measurement.

Inclusion Criteria:

• Patients with invasive femoral artery temperature monitoring

Exclusion Criteria:

• Pregnancy

Patients that undergo major abdominal surgery