Analysis on Failure Factors for Noninvasive Positive Pressure Ventilation in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Emergency Department

Objective: To investigate the factors associated with failure of noninvasive positive pressure ventilation(NPPV) in patients presenting with acute exacerbation of COPD(AECOPD) in emergency department.Methods: Forty-five patients admitted to the emergency department with AECOPD for NPPV treatment were retrospectively analyzed.The mode of ventilation is PSV plus PEEP.The patients were divided into NPPV success group and NPPV failure group.The changes of the arterial blood gas,respiratory rate,dyspnea scores(DS),and oxygenation indexes(PaO2/FiO2) were compared before and after 1-hour NPPV between the two groups.Results: Respiratory rate and DS were higher in NPPV failure group,but pH was higher in NPPV success group.Factors associated with failure of NPPV were respiratory rate 20 beats/min(OR=4.55,95%CI=1.22-16.97),DS≥5(OR=9.36,95%CI=2.1-42.8),and pH7.35(OR=10.7,95%CI=1.25-91.6) after one hour NPPV.Conclusion: Patients with RR20 beats/min,DS≥5,and pH7.35 had an increased risk of endotracheal intubation after one hour of NPPV.