Analysis Of Factors Related To The Failure Of NPPV In The Treatment Of AECOPD With Severe Respiratory Acidosis

Objective:Noninvasive positive pressure ventilation（NPPV）is the first-line treatment for acute exacerbation of chronic obstructive pulmonary disease（AECOPD）for respiratory failure.However,for patients with AECOPD combined with severe respiratory acidosis（pH<7.25）,whether it is suitable for first choice,which factors can be used as indicators for predicting efficacy,is still controversial.Therefore,this study retrospectively analyzed the clinical data of NPPV in patients with AECOPD complicated with severe respiratory acidosis,and explored the causes of NPPV treatment failure,providing a basis for clinical decision-making.Methods:This study collected 90 AECOPD patients with severe respiratory acidosis（pH<7.25）from January 2015 to July 2018 who were treated by NPPV in the Hospital of Anhui Medical University.First,the patents’gender,age,medical history,hospital stay,vital signs,laboratory tests,Glasgow Coma Scale（GCS）,acute physiology and chronic health score（APACH II）,clinical lung infection score（CPIS）and other indicators were collected.Then 90 patients were grouped according to efficacy,the patient who did not improve the condition,so as to choose endotracheal intubation or give up treatment or the death was classified as the failure group,and the condition improved was classified as the successful group.Comparing the clinical information between successful and failed groups,then used the single factor logistic regression to screen out the factors related to the efficacy of NPPV.Finally,multivariate logistic regression analysis was performed on the prognostic factors screened by single factor selection to screen independent influencing factors.Results:1.Ninety patients were enrolled,68（75.6%）were successfully treated with NPPV,and 22（24.4%）had failed.2.The scores of Glasgow coma score、APACH II score before treatment with NPPV and pH、PaCO₂、the scores of Glasgow coma score after 2-4 hours treatment with NPPV were significant factors associated with NPPV failure（P<0.05）.3.Applied meaningful indicators to univariate logistic regression,and analysis the following meaningful clinical indicators:the GCS score（P=0.001,OR=1.538,95%CI:0.950-1.987）,APACH II score（P=0.032,OR=0.877,95%CI:0.778-0.989）,GCS score after 2-4 hours NPPV treatment（P=0.001,OR=2.120,95%CI:0.960-1.007）、pH after 2-4 hours NPPV treatment（P=0.049,OR=0.338,95%CI:0.114-0.997）和PaCO₂ after 2-4 hours NPPV treatment（P=0.001,OR=0.933,95%CI:0.960¹.007）.4.Carried the multivariate logistic regression to analysis of single-factor meaningful indicators,and the indicators finally into the equation as the following:the GCS score after 2-4 hours NPPV treatment（P=0.029,OR=0.451,95%CI 0.221-0.923）and PaCO₂（P=0.011,OR=1.054,95%CI 1.012-1.098）after 2-4 hours NPPV treatment.Conclusion:NPPV is effective in treating AECOPD with severe respiratory acidosis.The lower the GCS score and the higher the PaCO₂ after 2-4 hours of NPPV treatment indicate the higher the likelihood of failure.Although the APACH II、GCS before the NPPV treatment,and the pH after 2-4 hours of NPPV treatment are not predictors of efficacy,but they are all associated with treatment outcomes and can be used in Clinical efficacy judgment for a short period of time.Therefore,when doctors apply NPPV to treat such patients,the GCS and PaCO₂ after 2-4 hours of NPPV treatment should be evaluated in time to identify the patients who have the high probability of noninvasive treatment failure,so as to adjust the treatment plan to improve the treatment plan in time to improve treatment success rate,and reduce the mortality.