Hypercapnic Failure in Acute Exacerbated COPD Patients: Severe Airflow Limitation as an Early Warning Signal.

Background: Hypercapnic failure is a severe complication of COPD disease progression, which is associated with a high morbidity and mortality. The aim of this study was to examine the association of comorbidity and clinical risk factors with the development of hypercapnia in acute exacerbated COPD patients.

Methods: In this retrospective monocentric cohort study, we examined the influence of the clinical parameters and the comorbidity of hospitalized patients with the acute exacerbation of COPD on the development of hypercapnia by performing multivariate logistic regression and a receiver operating characteristic analysis.

Results: In total, 275 patient cases with COPD exacerbation were enrolled during the period from January 2011 until March 2015, where 104 patients (37.8%) with hypercapnia were identified. The logistic regression analysis revealed severe airflow limitation (decreased FEV1) as the main factor associated with the development of hypercapnia. In the ROC analysis, we determined an FEV1 of 42.12%, which was predicted with a sensitivity of 82.6% and specificity of 55%, and an absolute value of FEV1 of 0.8 L, with a sensitivity of 0.62 and specificity of 0.79 as the cut off points, respectively. We could not verify an association with the patient's condition or the laboratory surrogate parameters of organ failure.

Conclusion: Severe airflow limitation is an important risk factor that is associated with hypercapnic failure in acute exacerbated COPD patients. Validation in prospective cohorts is warranted and should focus on more intensive monitoring of these at-risk patients.