1. Few eligible patients at study start
2. Patients received HFNC prior to intermediate care ward admission
3. NIV was locally considered a step-up therapy to HFNC
4. Full-face masks replaced the Helmet interface as local NIV standard

We aim to investigate whether the use of Continuous Positive Airway Pressure using a Helmet device (Helmet CPAP) will increase the number of days alive and free of ventilator within 28 days compared to the use of a High Flow Nasal Cannula (HFNC) in patients admitted to Helsingborg Hospital, Sweden, suffering from COVID-19 and an acute hypoxic respiratory failure.

A detailed description can be found in the study protocol published in Trials in Dec 2020:

Tverring, J., Åkesson, A. & Nielsen, N. Helmet continuous positive airway pressure versus high-flow nasal cannula in COVID-19: a pragmatic randomised clinical trial (COVID HELMET). Trials 21, 994 (2020). https://doi.org/10.1186/s13063-020-04863-5

Inclusion Criteria (all of the following):

1. Age ≥ 18 years
2. Sars-Cov-2 found in the upper or lower respiratory tract by PCR during the current disease episode
3. Peripheral oxygen saturation (SpO2) < 92 % despite conventional low-flow oxygen therapy of at least 6 L /min for at least 15 min
4. A decision to initiate HFNC or Helmet CPAP by the attending ward physician
5. The patient has given written informed consent to participate.

Exclusion Criteria (any of the following):

1. Need for direct admission to the intensive care unit for mechanical ventilation
2. Unconsciousness or drowsiness
3. Pneumothorax
4. Carbon dioxide pressure (pCO2) > 6 kPa in venous blood gas (VBG)
5. Underlying chronic obstructive pulmonary disease stage III-IV
6. A decision not to participate
7. Inability to comprehend the study content and give informed consent