Objective: NIV in properly selected patients (non-obtunded with a pH>7.19) can result in improved tidal breath, minute ventilation and prevent endotracheal intubation in COPD patients with hypercarbic respiratory failure. This study explores the efficacy of NIV in avoiding endotracheal intubation and surviving to discharge.
Method: a retrospective chart review was conducted on 30 consecutive deployments of NIV in hypercarbic COPD patients in the year 2003. Arterial blood gas. (ABG) Pre-NIV, post NIV, endotracheal intubation and survival to discharge were recorded.
Results: Demographics revealed 14 males, and 16 females; mean age was 74.4 years. ABG’s were all obtained within 24 hours of deployment. There were 25/30 (83%) responders with pre-NIV ABG of pH 7.29, PCO2 63.3 mmHg. and mean post –NIV ABG’s were pH 7.38, PCO2 52.6mmHg,▴pH was 0.0796, ▴PCO2 was10.7mmHg. Of the non-responders 5/30 (17%) mean ABG’s pre-NIV were pH 7.29, PCO2 53.0mmHg, post-NIV mean ABG’s pH were 7.24, PCO2 60.6 mmHg ▴pH -0.058 and ▴PCO2 0.7.6 mmHg. NIV success in avoiding EI was 22/25 (88%) Patients surviving to discharge 22/25 in the responder group.
The non-responding group had a pre-NIV ABG revealing a primary respiratory acidosis with no metabolic compensation or a concomitant metabolic acidosis that was predicted of failure on initial presentation. This has not been previously reported. We demonstated the high rate of success of NIV at avoiding endotracheal intubation with low mortality and high rate of discharge back to the community.
Further study is required to validate the predictive value of NIV failure in uncompensated respiratory acidosis on the initial arterial blood gas.
Robert Fleming, None.