After thyroid surgery, 0.6 to 4% of patients develop postoperative bleeding. 90% of this postoperative bleeding occurs within the first 48 hours. Most of the time, the complications are rapidly progressing and require immediate attention. Up to 0.6% of patients with postoperative bleeding die. In a clinical study with postoperative pressure measurements it could be shown that postoperative bleeding without interruption leads to a continuous increase in pressure in the neck, as is observed when coughing and pressing. Systematic invasive pressure measurement in the thyroid compartment after surgery might detect a continuous increase in pressure which is often caused by a growing haematoma, indicating serious post-surgery bleeding at a much earlier time compared to state of the art diagnostic workflow. n routine clinical care, detection of serious haemorrhage depends on the patients alerting symptoms even if post-operative intermittent monitoring of vital parameters and wound conditions is performed according to current medical guidelines and local instructions. Device-based, continuous haemorrhage detection within 36 to 48 hours after surgery would allow to objectively measure an increase in cervical pressure before symptoms occur, i.e. early detection of risk leading to timely therapeutic actions. Thus, the risk of serious complications like hypoxic brain damage and death caused by post-operative haemorrhage is minimized. In addition, the intervention team would be able to fine-tune necessary actions during the rescue procedure based on objective pressure values, e.g. the decision to open cutaneous sutures immediately or later in the operation theatre, and therefore reduce additional perioperative morbidity and increase patients' safety.

Inclusion Criteria:

• Age ≥18 years.
• Indication for thyroid surgery (e.g. total thyroidectomy, subtotal resection, partial resection or lobectomy) in routine clinical care according to applicable medical guidelines using all adequate surgical approaches.
• Signed informed consent

Exclusion Criteria:

- Intended use of drains

HEDOS will enrol and measure presumably 1,470 eligible adult patients and follow each of them for 1 month, assuming that 22 cases of clinically relevant haemorrhage within 48 hours following thyroid surgery will be observed. It will be conducted in Germany and Austria with about 50 clinical sites participating.