For patients on NIPPV or HFNO with persistent hypoxaemia or respiratory distress: • Check the equipment: inspect the exterior of the machine, the tubing (circuit), the mask for any sign of mechanical damage, confirm it fits securely without leak (if CPAP/BiPAP) and the filters are in place. Ensure the settings are appropriate and flow is maximized. • Check the oxygen source: there is sufficient oxygen available and flowing through the device. If FiO2 > 50% of oxygen is needed, the ventilator must have a blender. • Check there is no obstruction with secretions: patients with COVID-19 may have very thick secretions which may block small and large airways and cause sudden respiratory deterioration.