Pioneering New Uses for Existing Technology
Dr. Howard Jeffries (pictured far right with Dr. Mithya Lewis-Newby) co-wrote a chapter on cardiac ECMO in pediatric cardiac care for the 2007 edition of The Johns Hopkins Manual of Cardiothoracic Surgery.
When Dr. Harris Baden was a medical student at the Shriners Burn Hospital in Texas, he called his dad in the middle of the night and told him, “This is so tragic. I don’t think I can do this.” His father, a retired neonatologist, told him, “As scary as it is for you, think about how scary it is for the patients and their families, and how desperately they need your help.”
Nearly two decades later, his dad’s advice continues to guide Baden as he and his team take pediatric cardiac critical-care medicine to the next level.
Since joining the faculty in 2003, Baden’s been busy shifting institutional paradigms about the best way to care for children and teens with congenital heart disease, which is the most common birth defect.
In 2003, he and Seattle Children’s Chief of Cardiothoracic Surgery Dr. Gordon Cohen began the process of creating a distinct intensive-care service for cardiac patients — an innovative move undertaken by fewer than a dozen other pediatric hospitals in the nation.
Today, Baden and his team are pioneering the use of mechanical life-support devices to strengthen weak hearts prior to surgery and to speed recovery afterward. Early indications show that these novel therapeutic uses may dramatically improve survival outcomes for children with life-limiting heart conditions.
Powerful Restorative Therapy
Drs. Rob Mazor (left) and Harris Baden report 100% survival rates using a combination of ECMO and anti-arrhythmic medications on kids with heart failure related to arrhythmias — a technique that allows the heart to rest while preventing the irregular beat from damaging the heart muscle.
Historically, surgeons and intensivists used a type of heart-lung life support called extracorporeal membrane oxygenation (ECMO) as a last-ditch effort to save the most desperately ill children.
Now, Baden and his colleagues are exploring the use of ECMO as a powerful restorative therapy — particularly after the stress of high-risk surgeries such as transplants and single-ventricle repairs.
“The plumbing can be fixed, but aggressive surgical approaches and cardiac medications place a lot of stress on the heart. ECMO helps children survive by allowing the heart to rest and recover,” explains Dr. Rob Mazor, medical director of Seattle Children’s cardiac ECMO program.
“If you strained your bicep, you wouldn’t do curls,” says Baden. “It’s the same principle with the heart.”
Overcoming a Challenge
In the past, heart surgery was a relative contraindication for the use of ECMO. The anti-clotting drug heparin — required for children on ECMO — intensifies normal post-surgical bleeding, which can lead to complications and even death.
Seattle Children’s Cardiac ICU is one of a handful in the nation to regularly use a different type of life-support system to solve this problem.
For up to 24 hours after heart surgery, the Cardiac ICU team puts children on a centrifugal pump system (CPS) with heparin-bonded tubes in the pump. While the heart rests, the drug-coated tubing prevents clotting. After the post-surgical bleeding subsides naturally, children are put on heparin and moved to the ECMO system. The team also uses this approach to get control of chest bleeding when it continues to be a problem more than a few days after surgery.
Mazor says the results of this little-used method are excellent. The team finds that children on the CPS circuit with heparin-bonded tubing have less bleeding and less need for transfusion than children who used to be put on the conventional ECMO circuit and given heparin right after surgery. In fall 2008, Cohen presented these results at the Southern Thoracic Surgical Association meeting, and the paper was published in The Annals of Thoracic Surgery.
Rigorous Standards
Putting a child on ECMO is never done in a cavalier way. Baden and his team trade the risks associated with the child’s heart condition for the risks associated with mechanical assistance: infection, clotting and mechanical failure.
Baden says the secret to a child’s success on life support is the Cardiac ICU team, which consists of a distinct group of intensivists, fellows and nurses dedicated to cardiac critical care. “Daily repetition of practice is the key to our record of clinical excellence,” explains Baden.
Supporting the team’s incredible attention to detail are rigorous protocols instituted and tracked by Dr. Howard Jeffries, the Cardiac ICU’s director of quality.
In March 2005, Jeffries joined Child Health Corporation of America’s effort to reduce bloodstream infections — a process that includes a checklist for line placements and seven standard questions asked daily about each patient. Since then, the team has cut bloodstream infection rates in half and significantly decreased the number of days children need Foley catheters. In July 2007, Jeffries switched to central venous catheter lines (CVL) infused with antimicrobials; since that time, the unit has had only one CVL infection.
Looking ahead, Baden wants to track the long-term neurodevelopmental outcomes of kids on ECMO and continue training the next generation of cardiac critical-care providers.
“We can never lose sight of the need to take cardiac critical-care medicine to the next level,” he says. “But when we look toward the future, we always consider patients and families first.”
"Putting children on ECMO after heart surgery gives their weakened hearts a chance to fully rest and increases the probability that they will survive and thrive."
Dr. Harris Baden, chief, Cardiac Intensive Care Unit