March 2, 2023

Cannula shortage led to more invasive lung support for infants

A Vanderbilt study found that a three-year shortage of a common cannula used in young infants needing lung support forced hospitals across the United States to switch to a more invasive form of lung support,

A three-year shortage of a common cannula used in young infants needing lung support forced hospitals across the United States to switch to a more invasive form of lung support, according to researchers at Monroe Carell Jr. Children’s Hospital at Vanderbilt.

Published March 3 in the journal Pediatric Critical Care Medicine, the study evaluated the changes during the three-year period when the cannula was not available in the type of care provided to infants less than 29 days old who needed extracorporeal membrane oxygenation (ECMO), a life-sustaining therapy that temporarily takes over for the lungs and/or heart of critically ill patients to allow the body to rest and recover.

Infants needing only lung support, and not cardiac assistance, often can be placed on venovenous (VV) ECMO, a less invasive form of ECMO that uses a specific cannula placed in one of the large veins in the neck. Without this cannula, known as a dual lumen cannula, infants are more likely to be placed on the more invasive venoarterial (VA) ECMO, which requires placement of two cannulas through both a large vein in the neck and one of the major arteries supplying oxygen to the brain, the carotid artery.

The study, “Trends in Neonatal Extracorporeal Membrane Oxygenation During a Venovenous Cannula Shortage,” revealed medical centers transitioned to almost exclusive use of the more invasive form of ECMO, VA, in young infants during the time the VV cannula was unavailable.

Dupree Hatch, MD, MPH

The shortage highlighted a critical vulnerability in medical device availability for infants, says study co-author, Dupree Hatch, MD, MPH, medical director of the NICU at Monroe Carell and associate professor of Pediatrics/Neonatology in the Department of Pediatrics.

“A large portion of infants who need ECMO only need lung support, and that can be done by using VV ECMO,” Hatch said. “Our study showed that, compared to adults and pediatric patients who also lost access to the VV cannula, critically ill infants were particularly vulnerable to changes in their care models due to device availability. In this situation, few alternatives to the cannula taken off the market existed. So, once centers ran out of their supply of VV ECMO cannulas, our data suggests they started switching to VA ECMO for patients who would have normally received the less invasive, VV ECMO.”

Researchers found that VV ECMO for neonatal respiratory failure decreased after 2018 when the cannula went off the market. After 2018, the annual rate of VV ECMO decreased by about 50% each year compared to the use of VA ECMO. Prior to 2018, no significant trends were seen in the use of VV ECMO from 2010-2018. While the same cannula was discontinued from the market in adult and pediatric sizes in 2018, no change was seen in the rate of VV ECMO in the non-infant population. The study authors hypothesize this was due to the availability of other cannulas and techniques in large, older patients.

While lifesaving, the majority of VA ECMO use in young infants requires a surgeon to access their carotid artery, a major blood vessel in the neck that supplies oxygen to the brain. During VA ECMO, this artery can be permanently damaged with the potential for life-long effects. Reconstruction of the artery can be attempted but is not always viable. Hatch notes that long-term outcomes for infants with one carotid artery versus two are unknown. Some data suggests that neurologic outcomes may be better for infants who receive VV ECMO versus VA, but Hatch notes that more study is needed to understand full impacts and difference of VA versus VV ECMO in infants.

For the retrospective cohort study, authors collected and analyzed data from the ECMO registry of the Extracorporeal Life Support Organization (ELSO) for ECMO runs from July 2010 to July 2021. This cohort included infants less than 29 days old who received neonatal respiratory ECMO at U.S. medical centers during that period. The ELSO registry contains data on ECMO use, complications and outcomes from more than 500 centers worldwide.

“Thankfully our data suggest that despite the shortage, survival and short-term neurologic outcomes were unchanged, and families can be reassured by that,” Hatch said. “However, our study highlights the vulnerability of critically ill neonates to medical device shortages and should spur discussions about policies to incentivize device manufacturers to focus on developing products for critically ill neonates.”

The study was a multicenter collaboration with authors from Children’s Hospital of Los Angeles and University of Michigan. Other Vanderbilt/Monroe Carell authors include Stephen Patrick, MD, MPH, MS, Brian Bridges, MD, and Melissa Danko, MD.