SBT, as a routine extubation strategy for invasive mechanical ventilation, has been widely recognized. However, in recent years, studies have found that SBT may lead to delayed extubation, which has been confirmed in COPD patients but has not yet been widely accepted in patients with acute hypoxic respiratory failure. Both invasive mechanical ventilation and non-invasive mechanical ventilation are positive pressure ventilation, with the essential difference being the human-machine interface. The safe inspiratory pressure for non-invasive mechanical ventilation should not exceed 20cmH2O (1cmH2O=0.098 kPa). If the cause of respiratory failure is relieved or removed, respiratory function improves, and the patient has good airway protection ability and can tolerate non-invasive ventilation, the endotracheal tube can be removed as soon as possible to switch to non-invasive mechanical ventilation, thereby shortening the time of invasive mechanical ventilation and reducing the risk of complications. This study trial aims to identify the timing of early extubation sequential non-invasive mechanical ventilation in patients with acute hypoxic respiratory failure through non-invasive ventilation breathing tests, providing a basis for updating the process of invasive mechanical ventilation extubation.