Congenital High Airway Obstruction Syndrome (CHAOS)

What are the signs and symptoms of congenital high airway obstruction syndrome?

CHAOS does not typically produce any outward symptoms for the mother or baby while in the womb. The mother supplies nutrients and oxygen to the baby, so unborn babies don’t rely on their lungs to get oxygen. Because of this, changes in a baby’s lungs are harder to see before birth. After delivery, however, the baby relies on their lungs for oxygen and if their airway is blocked, the baby will not survive.

How do we make a CHAOS diagnosis?

We can often diagnose CHAOS during a fetal ultrasound. Over-expanded lungs and a flattened diaphragm are the most common signs we see on an ultrasound related to CHAOS. A fetal MRI can also help us locate the site of the blockage, which can be in the larynx (voice box), trachea (windpipe) or subglottic region (the lowest part of the larynx).

What can I expect from a fetal CHAOS test?

Fetal ultrasounds are very similar to a typical ultrasound but may take a little longer to help us see your baby better. We perform fetal MRIs the same as we would perform a typical MRI. If there are other fetal anomalies, we may also request an amniocentesis, which is a test we perform on a small sample of the amniotic fluid that surrounds the baby in the womb.

How do we treat congenital high airway obstruction syndrome?

CHAOS treatment depends on several factors. If the baby does not have evidence of hydrops, we will offer an EXIT procedure around 36 to 38 weeks gestation. An EXIT procedure is a complex operation that helps deliver babies who may not be able to breathe after delivery. In an EXIT procedure, we deliver your baby while it is still on placental circulation, which means that the baby is still receiving necessary oxygen from the mother through the umbilical cord.

If we identify fetal hydrops, treatment depends on your baby’s gestational age:

• Before 30 weeks, for a baby with CHAOS and fetal hydrops, we will offer fetoscopy to open the obstruction. We first place a camera into the uterus. We then move it through the baby’s mouth, into the back of the throat and into the upper airway and create an opening through the obstruction to relieve the pressure that has built up.
• After 30 weeks, for a baby with CHAOS and fetal hydrops, we will offer an EXIT procedure. Once we deliver the baby, we create a hole through the obstruction and place a breathing tube into that hole. If that is not feasible, we will perform a tracheostomy, which surgically places a breathing tube through the neck and into the trachea to help your baby breathe.

Why choose us for treatment of congenital high airway obstruction syndrome?

CHAOS is a rare condition, so it’s hard to find fetal care teams who are experienced in caring for it. We have an expert team composed of maternal fetal medicine doctors, pediatric surgeons, otolaryngologists, fetal anesthesiologists and neonatologists who are well-versed in caring for babies with CHAOS.

Children’s Hospital Colorado has an outstanding group of fetal care specialists at our Colorado Fetal Care Center who have a wealth of experience with both fetoscopy and EXIT procedures. EXIT procedures are complex and require a large and specialized team operating with state-of-the-art equipment and rooms. You’ll find all that at our Center.

All our specialists have additional training and education in working with families who have prenatal diagnoses. You’ll receive care from imaging specialists, nurses, therapists and doctors who work only with families like yours. After your baby is born, they’ll recover and grow in our Level IV (four) Neonatal Intensive Care Unit (NICU), which holds the highest possible designation for NICUs and is staffed by one of the most experienced teams in the country.

What are long term outcomes following CHAOS?

EXIT procedures have helped improve survival rates, but kids born with CHAOS commonly need a tracheostomy and have speech impediments.

Will my baby need a tracheostomy?

It depends on how long the obstruction was in place. Tracheostomies are common for kids with CHAOS, but they may not be permanent.

Does this affect future pregnancies?

Mothers who undergo an EXIT procedure will need to have a Caesarean section for all future pregnancies.