Surveillance and monitoring of patients with respiratory failure before or after undergoing mechanical ventilation is an underdeveloped area compared to the many possibilities of monitoring other non-invasive vital signs that we currently have.

Severe respiratory failure usually affects oxygenation and ventilation. Continuous or frequent non-invasive monitoring of oxygenation is performed with pulse oximetry, with a margin of error between 1 and 4% of arterial oxygen saturation of hemoglobin. Ventilation cannot be fully monitored in non-intubated patients: Measurement of respiratory rate (RR) outside the Intensive Care Unit (ICU) is usually performed intermittently and manually by the nurse, often with a wide margin of error and, regarding tidal volume (VT), it cannot currently be monitored either directly or indirectly in non-intubated patients because the measurement itself interferes with respiration. Similarly, data on inspiratory and expiratory flows cannot be obtained, which are also altered in certain pathologies. The technique considered as a "gold standard" is spirometry, which requires the collaboration of the patient, and the interpretation of the results depends on the performance of the technique in a standardized way. Spirometry offers a single value; continuous monitoring is not feasible and due to the bias of the technique.

More studies are needed to rule out the existence of different breathing patterns of acute respiratory failure and to identify outcome differences between them before recommending different support or treatment approaches.

In a preliminary not published study conducted with healthy volunteers, a good correlation was observed between changes in temperature inside the Venturi mask using two TSC50 thermistors and breathing pattern recorded by thoracic and abdominal plethysmographic bands.

HYPOTHESES: Monitoring respiratory activity, including both RR and the respiratory pattern (tidal volume, inspiratory flow, and the inspiration-to-expiration ratio), could enable early detection of respiratory patterns associated with the worsening of patients with COVID-19 pneumonia and severe pneumonia of other origins.

OBJECTIVES

Main Objective:

To evaluate the ability of the respiratory pattern to early detect respiratory deterioration in patients hospitalized pneumonia before requiring mechanical ventilation.

Specific Objectives:

To describe the initial respiratory pattern and its evolution throughout the hospital stay of patients with acute respiratory failure caused by SARS-CoV-2.

To describe the evolution of the respiratory pattern in patients with bacterial pneumonia admitted to the hospital who require supplemental oxygen.

Inclusion Criteria:

• Confirmed diagnosis of COVID-19 pneumonia, community-acquired or hospital-acquired with moderate, severe, or critical severity criteria as defined by the World Health Organization, OR Diagnosis of presumably bacterial pneumonia FINE III, IV or V
• Requirement for oxygen supplementation to achieve oxygen saturation (SpO2) greater than 92%
• Signed informed consent.

Exclusion Criteria:

• Non-invasive ventilation or mechanical ventilation at the time of evaluation
• Chronic noninvasive ventilation or oxygen therapy
• Inclusion in experimental treatment studies where the administered treatment is unknown
• Other more plausible cause of acute respiratory failure (ARF)

Patients with pneumonia admitted to the Intensive Care Unit, requiring oxygen supplementation to achieve an oxygen saturation (SpO2) greater than 92%.