Non-invasive ventilation (NIV) provides ventilation without an artificial airway. It can be negative pressure or positive pressure. Positive pressure NIV uses an interface like a mask to deliver ventilation. NIV is used for conditions like asthma, pneumonia, heart failure, and weaning from ventilation. It reduces the need for intubation and has benefits like lower mortality, shorter hospital stays, and reduced complications compared to invasive ventilation. Proper patient selection, interfaces, settings, and monitoring are needed to effectively use NIV.