How Successful is Non-Invasive Ventilation Treatment that is Initiated in the Emergency Department in Cases of COPD Exacerbations with Acute Hypercapnic Respiratory Failure? Can We Predict Treatment Failure?

Abstract

Objective: We aimed to investigate the success rate of non-invasive ventilation (NIV) in wards and the predictors of failure in cases of chronic obstructive pulmonary disease (COPD)-related acute hypercapnic respiratory failure (AHRF). Methods:The was a retrospective study conducted in a tertiary teaching hospital between May 2011 and 2013. Patients who were admitted to the emergency department (ED) because of COPD with AHRF were evaluated; 544 patients who initially received NIV in ED and were transferred to wards were included. Patient characteristics, baseline and follow-up pH values, and partial arterial carbon dioxide (PaCO 2 ) values were recorded. Baseline pH values were categorized as severe (pH<7.26), moderate (pH≥7.26-7.30), and mild (pH≥7.30) acidosis. According to the in-hospital outcome, patients were classified in 2 groups: Group 1: home discharge, Group 2: death or intensive care unit transfer.Results: Treatment resulted in success in 477 (88%) patients. Albumin levels were significantly low and the mean Charlson index (CI) score was significantly high in Group 2. Admission pH and PaCO 2 values did not affect the treatment outcome. Patients in Group 2 had higher PaCO 2 and lower pH values as well as a lower level of decrease in PaCO 2 values within 2 hours of treatment in ED. Similarly, higher PaCO 2 and lower pH values at the end of the first day in wards were indicative of NIV failure (p<0.05). Conclusion:The success rate of NIV in wards in cases of AHRF is high. Patients with low albumin levels and higher CI scores have worse response to treatment. pH or PaCO 2 values after a few hours of treatment and not the baseline pH or PaCO 2 values are better predictors than the baseline pH and PaCO 2 values.