At Children’s Hospital Central California, doctors work around the clock to save a critically ill toddler struggling to recover from his third corrective heart procedure for a congenital defect in which he has only one ventricle. Meanwhile, an agitated premature 6-month-old infant with lung disease becomes almost inconsolable despite his nurse’s numerous attempts to calm him.
Both pediatric patients were on mechanical ventilation, a common device using breathing tubes to assist or replace spontaneous breathing. In an effort to improve the patients’ conditions, Children’s pediatric specialists transitioned the toddler and infant to a unique mode of mechanical ventilation that the Hospital recently began offering first in the pediatric intensive care unit (PICU) and now the neonatal intensive care unit (NICU).
Called Neurally Adjusted Ventilatory Assist, or NAVA, this cutting-edge approach allows patients to breathe more naturally, improving patient-ventilator synchrony and comfort while often reducing peak airway pressure and sedation. With about 85 total cases to date, Children’s is the largest pediatric provider of NAVA in California and the only NAVA provider in the region. Children’s is collaborating with other medical facilities to research and document NAVA patient outcomes and benefits, as well as working to improve this innovative technology that could transform mechanical ventilation.
Another option to help improve outcomes
“Once the baby was put on NAVA, he immediately relaxed – the NICU nurse who was taking care of him said she couldn’t believe it,” said Larry Nicol, a registered respiratory therapist and PICU clinical educator at Children’s.
The toddler also saw dramatic changes. The little boy’s heart condition caused him to be extremely sensitive to the conventional mechanical ventilator’s high pressure, causing him to “fight” the ventilator with every breath. “He was headed in a downward spiral and his situation had become life-threatening,” said Dr. Harry Kallas, a pediatric intensivist. “We needed to do something different. NAVA allowed us to get the gas exchange we needed with lower pressure than other ventilators.”
After several days on NAVA, the youngster transferred to non-invasive NAVA that uses only a mask. With the help of NAVA technology, he had a very rapid recovery and soon was weaned off mechanical assistance completely.
“NAVA is a very positive modality that adds to our artillery of options to care for our patients,” said Dr. Kallas. “It’s not for everyone but it has made a big difference in some of our most difficult cases.”
Improved outcomes like the ones described are largely anecdotal – but the seeming link between the use of NAVA and enhanced care is difficult to ignore. In addition to recording and researching NAVA results, Children’s is developing a formal process to identify NAVA candidates. Other anticipated benefits of NAVA being studied include reduced time on a ventilator and incidence of infection, and decreased length of hospital stay and costs. Children’s is also working with Maquet, the company that offers NAVA, to refine the technology as needed.
How NAVA works
The NAVA mode monitors the brain’s signal that is transmitted to the diaphragm (the largest respiratory muscle) by way of a special feeding tube placed in the stomach. That signal is then sent from the feeding tube to the ventilator, and the ventilator gives the patient the breath.
“NAVA is the closest thing so far to natural breathing,” said Dr. Jorge Montes, medical director of Children’s PICU. “If the brain sends a big signal to breathe, the ventilator gives a big breath; if the brain sends a small signal, a smaller breath. The amount of support given to breathe is dependent on the strength of the signal coming from the brain. Less support is required in this mode to achieve the same results compared to other ventilators.”
Children’s acquired the new FDA-approved technology in part based on experience with a similar mode of ventilation that two caregivers at Children’s developed. Dr. Nadarasa Vishveshwara (also known as “Dr. Vish”), a specialist in the care of premature babies, and Bruce Freeman, an engineer and registered nurse, created a ventilator that automatically sensed each time a newborn was ready to take a breath. The machine called Synchronized Airway Ventilation for Infants (SAVI) was utilized for 20 years at Children’s until 2005 and at other medical facilities across the country and around the world.
“SAVI had the electrodes outside the patient’s body rather than inside,” explained Dr. Vish. “We saw improved outcomes with SAVI and think NAVA could prove the same.”