Abdominal surgical incisions often lead to superficial surgical site infection (SSI). SSI is characterized by heat (calor), pain (dolor), redness (rubor), and swelling (tumor). The aim of this study is to measure calor, rubor and tumor with electronic sensors. Therefore, a multisensory patch is proposed which measures the tissue surrounding the incision once per day.

Inclusion Criteria:

• The subject requires acute abdominal surgery due to perforation of the intestinal tractus (i.e., contamination upfront).
• The subject's incision is closed with either sutures or staples (by primary intention).
• The subject is 18 years or older.
• The subject can understand the patient information/ consent form and is capable of making his/her own decision.
• The subject is accompanied by an acquaintance who can give the second consent.

Exclusion Criteria:

• The subject has a known allergy to (silicon) adhesives.
• The subject states to be pregnant or planning to become pregnant.
• The subject receives medication that is contraindicated to excessive light exposure (e.g. Tetracylines, Doxycycline, Phenothiazines, Dacarbazine, Ketoprofen, Lomefloxacin). This criterion will be implemented in order to exclude the possibility of local skin irritation from prolonged irradiation by LED-light.
• The subject has an implantable device with a battery (i.e. pacemaker or other active implant).
• The subject has tattoos on the abdomen.