Hospital volumes influence ECMO outcomes in adults

Annual hospital extracorporeal membrane oxygenation (ECMO) case volume may influence mortality, particularly in adults, according to an analysis of international registry data.

Researcher Ryan P. Barbaro, MD, of the pediatric critical care division at the University of Michigan in Ann Arbor, and colleagues analyzed data from 1989 through 2013 in the Extracorporeal Life Support (ELSO) Registry. ELSO encompasses data for more than 56,000 patients from across 290 centers. Of this, the research team developed three groups: neonates (0 to 28 days), children (older than 28 days to less than 18 years) and adults (18 years and older).

They performed several analyses, including trends over time and hospital volumes and they also analyzed these groups against usage of the three different forms of ECMO: respiratory, cardiac and during cardiopulmonary resuscitation (ECPR).

Among adults, pediatric patients and neonates, overall mortality rates with respiratory ECMO were around 43 percent, 43 percent and 29 percent, respectively. Mortality rates with cardiac ECMO were about 60 percent, 49 percent and 59 percent, respectively. Meanwhile, with ECPR, mortality rates were 71 percent, 59 percent and 59 percent, respectively.

Over time, they found that among neonatal patients, ECMO volumes decreased through the 1990s before stabilizing. On the other hand, pediatric and adult volumes increased over time, particularly in high-volume centers and adult cases. Generally, while unadjusted mortality rates where lower at hospitals where higher volumes of patients were treated across all types of ECMO and all age groups, adjustments showed outcomes were more statistically significant for neonates and adults.

Barbaro et al found that from 2008 on, hospital volume played a significant role in adult mortality rates, whereas among children and neonates, the association was not as strong. No specific recommendations were made about volume, however.

“As use of ECMO rises, it will be very valuable to understand how best to provide this care, because it's resource-intensive and carries a high risk of complication and death,” said Barbaro in a press release. “If volume is associated with better outcomes, we as a medical community need to be selective about where to add new centers, and look at distance between centers and outcomes at each one. But this has to be balanced against the risk of transferring very delicate patients.”

The article appeared online Feb. 19 in the American Journal of Respiratory and Critical Care Medicine.