Prospective, controlled, randomized crossover volunteer study to investigate the effect of hyperoxemia due to inhalation of oxygen (80% inspiratory fraction) via reservoir-face-mask on blood coagulation, especially platelet function, as measured by thrombelastography. According to results of basic animal and in vitro investigations, hyperoxemia may activate platelets by means of reactive oxygen species. This study aims at investigating a possible pro-coagulant effect of hyperoxemia in healthy volunteers. Additional studies on possible mechanisms are integrated.

• Trial with medical device

Inclusion criteria:

• informed consent; no coagulation disorder or other illnesses;
• non-smoker;
• women: no pharmacological contraception, negative pregnancy test;
• 25-45 years old; no medication; no acute or chronic airway problems;
• for 24 hours before study: no extreme physical activity, no polyphenol-containing food (red wine, apples, cabbage, garlic);
• for 48 hours: no caffeine-containing drinks, no dark chocolate.

Exclusion criteria:

• Lack of one of the inclusion criteria;
• allergy or incompatibility to substances/materials applied in the study;
• very thin veins/arteries.