Oxygenation with high-flow nasal cannula with 100% oxygen have now been evaluated in a number of studies and the data are convincing. The THRIVE technique is able to oxygenate patients safely and vital parameters has been shown to be stable. But it is of great importance to evaluate this new concept regarding other potential negative physiological aspects such as biological stress response detected by blood-bourne biomarkers before implementing it into clinical practice.

Inclusion Criteria:

1. Adults, >18 years old.
2. Laryngeal-surgery where apnea is of benefit for the surgeon (eg. intraoral or laryngeal surgery).
3. Capable of understanding the study information and sign the written consent.

Exclusion Criteria:

1. American Society of Anaesthesiologist severity score >2
2. New York Heart Association score >2
3. Pacemaker or ICD.
4. Body Mass Index >35
5. Pregnancy
6. Manifest cardiac failure or coronary disease
7. Severe gastrointestinal reflux.
8. Neuromuscular disorder