Hospitals that frequently treat acute COPD exacerbations using noninvasive ventilation – a practice known to reduce mortality, length of stay, and the need for more invasive treatment – did not have better patient outcomes than did hospitals that used noninvasive ventilation less frequently, according to a report published in Annals of the American Thoracic Society.

Acute COPD exacerbations are “one of the few conditions with high-level evidence demonstrating the benefits of noninvasive ventilation in patients with respiratory distress,” and the treatment has been widely adopted for this patient population. However, for noninvasive ventilation to succeed, patients must be carefully selected and closely monitored, and a multidisciplinary team of nurses, respiratory therapists, and physicians must coordinate the treatment, often across multiple hospital settings, said Anuj B. Mehta, MD, of The Pulmonary Center, Boston University, and his associates.

Until now, it was not known whether hospitals with a high volume of noninvasive ventilation develop specialized expertise and thus deliver superior patient outcomes, or whether a high volume results from suboptimal patient selection or otherwise puts a strain on a hospital’s staff and thus produces poor outcomes. To examine this question, Dr. Mehta and his associates analyzed information in a database enrolling adults treated at 252 California hospitals for acute COPD exacerbation. They focused on 37,516 hospitalizations that occurred during a single year.

Overall, 9.3% of these patients received noninvasive ventilation. The median annual case volume of noninvasive ventilation for any indication was 64 per hospital. But rates of noninvasive ventilation varied widely across hospitals, with 40% of facilities significantly deviating from this median rate.

“Contrary to our hypothesis, we did not observe significantly lower COPD mortality” in hospitals with high volumes of noninvasive ventilation. For individual patients, admission to a hospital with a high volume of noninvasive ventilation was associated with significantly higher odds of treatment failure (adjusted OR, 1.95), and such failure was associated with significantly higher odds of death (adjusted OR, 1.81). In addition, at the hospital level, a high volume of noninvasive ventilation was associated with a significantly higher risk of treatment failure, which in turn was associated with higher patient mortality.

“Hospitals with higher total noninvasive ventilation case volume tended to use [it] in patients with more comorbidities and acute organ failures, suggesting potential overuse among patients at higher risk of treatment failure. … [This] may partially explain why hospitals with high rates of using an evidence-based intervention did not achieve significant mortality benefits,” Dr. Mehta and his associates said ( Ann Am Thorac Soc. 2016;13[10]:1752-9 ).

They added that the wide variation between hospitals in failure rates for noninvasive ventilation were likely attributable to unmeasured hospital factors, speculating that the site of treatment (regular ward vs. ICU); staffing ratios for nurses, respiratory therapists, and physicians; and the intensity of patient monitoring, such as the frequency of blood-gas measurement, may contribute.

“High rates of treatment failure at some hospitals suggest that further work is needed to maximize the real-world effectiveness of noninvasive ventilation, even for an indication [backed by] strong evidence,” the investigators said.

The National Institutes of Health; the National Heart, Lung, and Blood Institute; and Boston University supported the study. The investigators’ financial disclosures are available at