ROLE OF NIV IN ACUTE EXACERBATION OF COPD

Abstract

Background: NIV in the management of acute type II respiratory failure in COPD patients represents one of the major technical advances in respiratory care, reducing mortality, need for intubation and its potential complications. Despite its benefits, NIV is not successful in all cases and the ability to predict those likely to fail to respond to NIV is important.

Objectives: To study the effectiveness of   NIV  in patients with  AECOPD, find out the factors associated with the successful outcome of patients receiving  NIV and to assess mortality in these patients.

Study-Design: Prospective observational hospital-based study.

Material & Methods: Patients presenting with acute exacerbation of  COPD  with hypercapnic respiratory failure requiring  NIV, were included in the study. Clinical parameters and  ABG parameters were recorded at admission (before initiating NIV) and the same were reevaluated after initiating  NIV  at 1 hr, 4 hrs, 24 hrs, 48-72 hrs and at death/discharge of the patient. Need for intubation, success (and failure rates), and a number of deaths during hospital stay were also recorded.

Results: Total number of 172  patients were included in the study. NIV  was  successful  in  123  patients(71.5%) while failure was  observed  in  49  patients(28.5%). Out of  49  patients who required intubation, 31 patients expired during a hospital stay i.e. 18% (of total). Among the surviving  141  patients, 43  expired within  6  months of discharge i.e.  30.5 %. The success group had lower RR, lower heart rate and greater oxygen saturation compared to failure group at admission. The success group was found to have higher pH, lower PCO2  and higher  PO2 compared to failure group at admission. Higher GCS, higher PO2, lower  RR and lower PCO2 at admission, predicted  NIV  success.

Conclusions: NIV is highly effective in acute exacerbation of  COPD with hypercapneic respiratory failure, reducing need for  endotracheal  intubation  and  mortality  to  a great  extent. Failure   of  NIV  can  be  predicted  at  admission  by  low  GCS, high RR,  high  PCO2, and  low PO2. Once  NIV  is  started,  lack  of  improvement  in  various clinical and  ABG  parameters within  1 hr  and 4  hrs of  initiating  NIV, is  a  predictor of  failure. These   patients  are   more  likely  to  undergo  mechanical ventilation.