Ventilator advances for babies are proving vital for adults

When Sabina Checketts holds her hand a certain way, the tiny scar on its back resembles a rocket ship. Checketts received the scar during the first few days of her life, during a tenuous struggle for survival, after she was born at 28 weeks, or 12 weeks premature. Her rocket ship scar, and a few other small ones, are marks left by lines inserted into her tiny body to keep her alive.

“I don't point these out to parents,” Checketts says, “but to me they're badges of honour, because I survived.”

The parents to whom Checketts refers are those of her patients. Thirty-three years after her early birth, Checketts now works as a neonatal doctor. Today, she has at her disposal vastly improved technologies and techniques over what existed three decades ago. Those mostly uncelebrated advances are now driving better outcomes for other premature babies, and more hope for their parents.

Very fragile lungs

For premature babies, one of the most critical issues is something few ever consider: breathing. A pivotal advance in neonatal medicine, and one that has a major impact in adult critical care, has been the development of better ventilators.

“One of the main challenges for premature babies is with ventilation,” Checketts says. “Their lungs are quite stiff when they're first born because they're so immature. They're very fragile.”

The ventilator that helped Checketts survive was a far cry from what she sees in neonatal units today. “We've gone from a mode of ventilation where you were breathing for the baby to one now where we can breathe with the baby as well,” she says.

One such technique is called Neurally Adjusted Ventilatory Assist, or NAVA, which was developed by Getinge, a global leader in intensive care technology for both infants and adults.

Before NAVA, ventilation technology employed sensors in the breathing tube. When a baby was trying to breathe in, the ventilator was triggered and supplied a breath. But in many cases there was a mismatch in timing, which caused different kinds of asynchrony. Sometimes the ventilator did not supply air and oxygen when the lungs called for it, or forced air into frail lungs that were not ready for it. The issues were only amplified by premature babies' tendency to take short, rapid and variable breaths.

“NAVA is a way to do a little better,” says Sherry Courtney, a director of clinical research in neonatology, who has worked with premature babies since the 1980s. “The diaphragm is a muscle. When it contracts, we're going to breathe. When it relaxes, we're going to exhale. So NAVA senses the breathing using a catheter that goes down into the stomach and rests close to the diaphragm.”

Electrodes on the catheter sense contractions in the diaphragm, resulting in an almost instantaneous signal that the patient wants to breathe. Synchronously, the ventilator supplies air. And when the electrodes sense the end of diaphragmatic contractions, the ventilator allows exhalation.

“NAVA just provides a little support, depending on the breath. The patient can be breathing as the patient wishes. Deep breaths, shallow breaths, long breaths, short breaths, bigger volumes, smaller volumes. That's the way people breathe,” says Courtney. “And NAVA may allow all of that to happen, along with making sure everything is synchronized to the pattern of the breathing. So it's a very useful way to ventilate because it increases the comfort for the patient.^7,8"

Courtney says she's observed many babies who switch to a NAVA-enabled ventilator almost immediately become more comfortable and less irritable. Their oxygen needs decrease, as do pressure and volume requirements. Babies can be more restful and concentrate energy on the single most important thing they can do during their premature stage—grow.

From premature babies, care for adults

While the use of NAVA for premature babies is relatively well known, many doctors outside Europe don’t know it is also approved for adults. Most adult patients on ventilators generally start with a functioning diaphragm, but it can weaken quickly if the ventilator breathes too much for them under a prolonged time.

Getinge Medical Director Miray Kärnekull says that advanced ventilator technologies, like NAVA, are used regularly in adult patients in Europe to help them maintain diaphragm strength, shorten their time on the mechanical ventilator and improve patient comfort.”

“With conventional ventilation modes there is no monitoring of the diaphragm activity^1,2. So you have no idea actually what's happening there,” Kärnekull says. “Driving too much air into the lungs, for instance, suppresses the respiratory drive and weakens the diaphragm. This can cause problems when it's time to wean a patient off the ventilator^3,4. NAVA helps mitigate those challenges.”

NAVA also improves patient comfort. Adults will often fight the ventilator, which can lead to a patient with a high level of anxiety. To prevent that, doctors frequently prescribe increased levels of sedation. Because the mode of NAVA is synchronous with patient breathing, it tends not to interfere with the patient’s spontaneous breathing to the same degree. That may reduce the need for sedatives and promotes earlier weaning with fewer complications⁵.

“It’s really a groundbreaking technology”, Kärnekull says. “NAVA gives the clinician a way to personalize not only the ventilation, but also the weaning process for adult patients⁶. “And in a very recent multicenter randomized controlled trial, results showed that patients with acute respiratory failure on NAVA spent significantly less time on the ventilator and experienced less extubation failure compared to conventional lung-protective mechanical ventilation.⁹"

The introduction of NAVA is a clear leap forward from the day Sabina Checketts entered the neonatal unit, but it is far from the only one. Advances in the machines and the software that powers them now permit a level of personalization unimaginable one decade ago, much less three.

David A. Kaufman, MD, Pulmonary & Critical Care Medicine at NYU School of Medicine in New York, says that advanced machines, like Getinge's, can convey much more information about the patient's condition.

“The 2020 advanced critical care ventilators give us flexibility, give us information, give us fabulous ways of measuring—on a moment-to-moment basis—very sophisticated levels of interaction between patient and ventilator,” Kaufman says. “That helps us tailor what we do to individuals in a very refined way. We like to be sure that we can meet each individual patient's needs as specifically as we can, and today's top-line ventilators give us the tools to do that.”

For the treatment of medical emergencies too complicated and acute for even the most sophisticated ventilators, Kaufman points to the development of other techniques, gaining popularity in hospitals to support the ventilation. One such method, called Extracorporeal Life Support (ECLS), simulates the function of lungs or a heart that has ceased working.

“Basically, we take blood out of one of the big veins in the body,” Kaufman says. “We run it through a chamber where we are able to extract the carbon dioxide and put in a high concentration of oxygen. Then, that blood is injected back into another vein.”

Invented in the 1960s to facilitate cardiac surgeries with cardiopulmonary bypass, extracorporeal techniques and technologies have been refined to the point that they are used increasingly worldwide. In response, Getinge, a leading manufacturer of equipment used in extracorporeal support, has increased investment and production of components to meet demands.

ECLS is primarily a way to buy time. It can keep the blood oxygenated without damaging lungs in the most critical situations—like multi-organ failure—while doctors figure out how to save the patient. The technique has potential in the case of trauma, while a patient awaits organ donations, or in the treatment of acute infectious disease, when a ventilator can cause damage.

“There are times when people have such sick lungs, they're so wet, they're so heavy, they're so stiff, that the force that a mechanical ventilator needs to apply to get any gas into the lungs is very high,” Kaufman says. “ECLS allows us to make sure that we're not adding to the damage that's already occurring from the patient's underlying disease.”

The patient matters most

For Sabina Checketts, and physicians like her, such advances are a means to saving lives.

Checketts decided to become a doctor at an early age, after her mother routinely pointed out a man walking down the street on his way to the hospital and said, That’s the doctor who saved your life. The experience motivates her to be a positive force in the families of the babies she treats.

“When I talk to parents about the fact that I was premature, there's always a sense of surprise. I think even a little bit of shock, you know. Oh, oh, and you're a doctor,” Checketts says. “I think it's a nice way to say to them that prematurity shouldn't be a limit on what a child can do.

“I mean, the advances we've made in even just the last 10, 15, 20 years mean the outcomes are much better than they used to be. And seeing me, who developed before that, as a doctor for newborns, I give them a sense of hope and possibility, I think.”