Objective PB840 ventilator to explore non-invasive ventilation (NIV) in the ICU of the application,efficacy and safety.Methods Application PB840 Ventilator-Non-invasive mechanical ventilation in the treatment of the seven cases of different causes of respiratory failure patients,non-invasive ventilation in the treatment of 4 h,the blood gas (PaO2,PaCO2 and pH value) analysis and analysis of clinical symptoms to improve the situation.Results Patient before and after treatment of PaO2,PaCO2 and pH compared to the value there is significant difference.Target to improve the blood after treatment significantly (P<0.05),reduce or alleviate the symptoms of sick;cyanosis improved.However,leakage is still a major disadvantage,some patients can not tolerate when there is need to immediately replace invasive mechanical ventilation.Conclusion PB840 ventilator mode non-invasive ventilation can improve the patient′s respiratory failure and clinical symptoms of blood-gas target,but most critically ill patients should be carefully applied.