 Non-invasive positive-pressure ventilation NPPV is increasingly being used to manage patients with acute respiratory failure ARF in an effort to avoid the numerous negative sequelae associated with intubation and mechanical ventilation. In the USA, it is estimated that 20-30 of all patients placed on mechanical ventilation are treated with NPPV. Indications for NPPV include but are not limited to acute or acute-on-chronic hypercapnic respiratory failure, pulmonary edema, respiratory failure in immunocompromised patients or that due to chest wall deformity or neuromuscular disease. For NPPV to be successful, it is critical that the patient be cooperative and comfortable i.e. no pain as agitation and discomfort interfere with the success of NPPV. 