Bubbles Help Preemies Breathe Easier

One of the first challenges that a newborn baby faces is making the transition from life inside mom, where all of the oxygen comes from the placenta, to life outside the womb, where the lungs take over that task. Often, infants born prematurely are not fully prepared for that transition. In past decades, that usually meant that premature babies had to have a breathing tube in place and a ventilator to breathe for them.

In recent years, strides have been made in the development of devices that can help premature infants to breathe easier without requiring a ventilator. One of the most common of these devices is nasal CPAP.

The lungs of a baby born prematurely are not fully developed, and the chest wall and its muscles are not yet strong enough to hold the lungs open. The lung is much like a balloon. When a balloon is completely deflated, it is much harder to blow air into it than if it is partially inflated already. Premature lungs have a tendency to deflate, making them inefficient and ineffective.

CPAP stands for Continuous Positive Airway Pressure. The device works by giving pressure through prongs that fit in the nose to help keep the lungs from deflating, so they can work better. The type of nasal CPAP we use in the NICU at Texas Health Harris Methodist Fort Worth is called “bubble CPAP.”

The bubble CPAP system is very simple. A tube through which air and/or oxygen are flowing (the INSPIRATORY LIMB) attaches to one side of special nasal prongs that fit into the nostrils of the infant. Another tube attaches to the other end of the prongs to serve as a “release valve” for the air/oxygen (the EXPIRATORY LIMB). The free end of the expiratory limb is placed 5 centimeters deep into a bottle of sterile water or dilute acetic acid. The pressure delivered to the baby can be increased or decreased by changing the depth of the expiratory limb in the bottle. As air travels through the system, it comes out the expiratory limb and bubbles in the bottle, hence the name bubble CPAP.

Since we started using bubble CPAP a few years ago, the average number of days that our premature babies need to be on a ventilator has decreased dramatically. When parents see their tiny infants breathing comfortably without the need for a ventilator, they breathe easier, too.

- Dr. Fran Lynch
Neonatal ICU Physician

Diagram credit: Aly et al Peds 2001