The aim of this study is to determine whether there are any changes in the carbon dioxide partial pressure in medical staff while wearing a filtering face piece (FFP) 2 or FFP3 mask.

Furthermore, changes in the capillary oxygen partial pressure, the subjective respiratory effort and the breathing rate are measured.

In the fight against the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the personal protective equipment (PPE) of medical staff plays a special role. Since the pathogen can be transmitted via droplets, particle-filtering half masks (filtering face piece - FFP) are a substantial part of the PPE. The current data indicate that there may be an increase in the carbon dioxide partial pressure (PcCO2) in the blood when wearing an FFP2 / 3 mask during routine medical activity.

The aim of this prospective cross-over study is to compare the PcCO2 measured by capillary blood sampling from medical staff while wearing an FFP2 or FFP3 mask. The PcCO2 determined without a mask serves as a reference value. While no mask is worn, the PcCO2, the subjective respiratory effort, the breathing rate and the capillary oxygen partial pressure (PcO2) is measured. The study participants then wear an FFP2 or FFP3 mask for one hour, and the same parameters are collected. Subsequently, the participant switches to an FFP3 or FFP2 mask, and the last measurement is conducted after one hour.

Inclusion Criteria:

• medical staff working at the Vienna General Hospital
• oral and written consent to take part voluntarily in this trial

Exclusion Criteria:

• hypersensitivity / allergy against Nonylvanillamid, Nikotinsäure-beta-butoxyethylester or other component of "Finalgon Salbe"
• not Coronavirus disease-19 vaccinated
• pregnancy
• breastfeeding