Analysis of factors associated with failure of noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease

Objective To explore the related factors of noninvasive positive pressure ventilation(NPPV)failure for acute exacerbation of chronic obstructive pulmonary disease(AECOPD)complicated with respiratory failure.Methods The clinical data of 85 AECOPD patients presenting with type Ⅱ respiratory failure were analyzed retrospectively.According to the curative effect of NPPV,patients were divided into success group and failure group.The physiological and biochemical indicators,acute physiology assessment and chronic health evaluation(APACHE)Ⅱ score and Glasgow coma scale(GCS)on admission were compared,and frequency of complications of NPPV,the changes of the arterial blood after NPPV for 2 h were also analyzed comparatively.Results ①In failure group,the pretreatment APACHE Ⅱ score,serum C-reactive protein level on admission and frequency of complications of NPPV were significantly higher and GCS was significantly lower than those in success group(P0.05).②Before NPPV treatment,there was no significant difference in pH and PaCO2 between two groups(P0.05).In success group,pH was significantly higher after NPPV for 2 h and PaCO2 was significantly lower than those in failure group(P0.05).There was an significant increase of pH and a decrease of PaCO2 in success group on admission and after NPPV for 2 h(P0.05),while there was no significant changes in failure group(P0.05).Conclusion High APACHE Ⅱ score and low GCS,presence of complications of NPPV and no improvement in pH and PaCO2 after 2 h of NPPV are risk factors associated with NPPV failure.Patients with these risk factors should be considered a need of early invasive ventilation.