Continuous positive airway pressure (CPAP) with a helmet-like interface has been described as a safe strategy, with minimal contamination of the environment, improving the oxygenation of patients with acute respiratory failure (ARF) by COVID-19, avoiding intubation in more than half of the cases. ELMOcpap, developed in Ceará, was a great ally in the treatment of these cases during the pandemic in the state. It is estimated that among public and private services, more than 1.400 ELMOs have been applied to patients with COVID-19. However, the determining factors of the success and failure of its use in the different institutions in which it has been applied are still unknown. Therefore, it is necessary to survey all data associated with the use of the device.

Objectives: 1. To describe the effects of ELMO in the treatment of patients with hypoxemic respiratory failure due to COVID-19 in a database, in a systematic and standardized way, on clinical history, efficacy, safety, modes, duration of use, the occurrence of adverse events and early predictors of failure. 2. Determine the intubation rate of patients with COVID-19 hypoxemic respiratory failure who used the ELMO. 3. Identify the mortality rate of patients with hypoxemic respiratory failure due to COVID-19 who used the ELMO.

Methods: This is a retrospective, multicenter, observational, cohort study of recorded data from patients with COVID-19 hypoxemic respiratory failure who were treated with the ELMO. An online electronic form will be developed with REDCap, where the responsible investigator of each institution will be responsible for filling in the participants' data, ensuring adherence to the protocol and analysis will be carried out of the data of the patients of the participating services of the research that used the ELMO as treatment.

An online electronic form will be developed with REDCap, where the responsible investigator of each institution will be responsible for filling in the participants' data, ensuring adherence to the protocol.

The researchers involved will undergo qualified training and will receive a video, showing step-by-step how REDCap works, so that there are no doubts about the data collection process and to ensure the standardization of the collection protocol.

An explanation of the nature and objectives of the study will be presented to the research subjects, as well as its importance to society, health professionals and researchers.

The investigators will visit the hospital at least five times a week in the morning, afternoon and/or night shifts, for data collection, with monitoring and collection of outcomes being performed daily.

Inclusion Criteria:

• Data from adult patients diagnosed with COVID-19 described in medical records by laboratory detection of RNA of SARS-CoV-2, who used the Assisted Breathing Helmet - ELMO, will be recruited.

Exclusion Criteria:

• Illegible medical records or forms or with incomplete data that make it impossible to collect data will be excluded.

Patients with COVID-19, confirmed by laboratory detection of SARS-CoV-2 RNA, who used the Assisted Breathing Helmet - ELMO in referral hospitals in Fortaleza, Brazil.

Data will be collected retrospectively from adult patients admitted to the ICU and wards during the COVID-19 pandemic in Fortaleza.

An online electronic form will be developed with REDCap, where the responsible investigator of each institution will be responsible for filling in the participants' data, ensuring adherence to the protocol.

The investigators haven't developed a plan for sharing, but would be open to share unidentified data for research or public health purposes.