Congenital High Airway Obstruction Syndrome (CHAOS)

Congenital high airway obstruction syndrome (CHAOS) is a rare, serious birth defect that blocks your unborn baby’s airways and causes their lungs to fill with fluid. This puts increased pressure on your baby’s heart, which decreases its ability to function properly. It may also cause fluids to build up in the airway, abdomen and within the skin.

The obstruction can occur in different parts of the airway, from the voice box to deep in the chest. The obstruction is generally a web or membrane that stretches across the airway, causing the blockage. The obstruction pictured in the accompanying image shows a blockage in the baby's airway causing increased fluid in the belly and pressure on the heart.

Until recently, survival rates for babies with CHAOS have been very low. But there is reason for optimism with new procedures proving successful at treating this dangerous condition. At Orlando Health Women’s Institute Fetal Care Center, our extensively trained fetal care specialists have the expertise to help you and your baby, from diagnosis to birth and beyond.

What Causes CHAOS?

We do not yet know what causes CHAOS, which occurs in about 1 in 50,000 births. It is possible there is an unidentified genetic link. The condition, for example, may be a component of Fraser Syndrome, a rare genetic disorder that causes malformations before birth.

How CHAOS Is Diagnosed

Often the first signs of congenital high airway obstruction syndrome appear during routine ultrasound imaging at 18 to 22 weeks’ gestation. When the lower airway is obstructed, the impact will be visible in the lungs and other internal structures. The lungs may appear to be extremely large, the heart may appear elongated or compressed, and there may be signs of fluid accumulation in the abdomen. Magnetic resonance imaging (MRI) may also be used to gauge the severity of the blockage and to rule out other conditions. Given the rarity of this condition, it is critical that you rely on fetal specialists to be certain of the diagnosis.

Treatments for CHAOS

Managing a pregnancy complicated by CHAOS demands regular monitoring through ultrasounds and careful supervision by your care team – in coordination with your obstetrician. In rare instances, CHAOS will resolve on its own. If it doesn’t, our fetal care specialists will be there to help your baby. In most cases, our fetal care team will closely monitor your baby through ultrasounds until baby has reached full term or is medically in need of delivery to sustain life. This will be through a procedure known as ex utero intrapartum treatment (EXIT), which allows our neonatologists to be in the operating room during delivery and provide immediate life-sustaining care for baby. Because of the extended delivery time, this will be performed under general anesthesia. Your baby will remain attached to the placenta and umbilical cord until the airway obstruction is cleared or bypassed. Your baby continues to receive critical oxygen and nutrients from the placenta during the procedure.

In some instances, it may be possible to clear the obstruction while your baby is still in the womb. Our compassionate team will work with you to determine which approach is best for you and your baby.

Prenatal Surgical Options

The first is in utero laser surgery, which uses a tiny scope to pass through the mother’s skin, her uterus and into the fluid surrounding the baby. Next, the same scope is passed into the baby’s mouth, back of the throat and into the airway (trachea). The scope is moved down the airway to visualize the obstruction (web or membrane). Through the scope a tiny laser fiber is moved to just above the obstruction, laser energy is released and a hole or holes are made, opening the airway and allowing the trapped fluid in the lungs to escape. This treatment is successful about half the time.

The second in utero surgery treatment is a newer procedure that has only been performed recently and requires the mother to undergo general anesthesia. Her abdomen and uterus are opened similar to a cesarean delivery, and the baby’s head and neck are brought out of the uterus. With the baby’s neck exposed, a tiny tube called a canula is placed through the neck and into the trachea below the obstruction. This allows the trapped fluid in the lungs to escape through the canula. The baby’s neck and head are placed back into the uterus, the uterus and abdomen of the woman are closed and the pregnancy is continued. The hope is to allow the baby to keep developing and the lungs to heal, the heart function to return to normal, and excess fluid in the baby’s abdomen and skin to slowly go away. This second therapy is not a cure. The baby will require delivery by the EXIT procedure to secure the airway at delivery and the baby’s transition to the NICU.

After Birth CareAfter Birth Care

Immediately after birth, your baby will be taken to our neonatal intensive care unit for evaluation and further treatments, if needed. Initially, your baby will likely need breathing assistance and feeding through an IV tube.

It is difficult to predict how long this level of intensive care will be needed.

As your baby builds strength, we will make sure you and your family are ready to care for your child at home. You will be fully supported by a specialized team that includes surgeons, nurses, respiratory therapists, lactation consultants and social workers.

There is still much to learn about this rare condition. But we are making meaningful strides at improving the long-term outcomes for children with CHAOS.

Meet Cassian

When Cassian was diagnosed in utero with congenital high airway obstruction syndrome (CHAOS), a condition described as "devastatingly fatal," his family turned to the experts at Orlando Health Women's Institute. In a rare in utero surgery, the team placed a tracheostomy to relieve life-threatening fluid buildup and give him a chance to keep growing. He was later delivered via an ex-utero intrapartum treatment (EXIT) procedure, allowing for immediate, life- sustaining ventilation before he ever took his first breath. After delivery, Cassian spent 132 days in the NICU before he went home just in time for Christmas. "Thank you doesn't even come close," his mother said.

Schedule an Appointment

Learn more about our services by scheduling an appointment with one of our fetal care specialists. Please call (321) 843-1414.

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