Understanding Congenital High Airway Obstruction Syndrome?
What is a CHAOS?
Congenital High Airway Obstruction Syndrome (CHAOS) is a rare condition present before birth in which a baby’s upper airway (the windpipe or larynx) is partially or completely blocked. This blockage prevents normal movement of fluid out of the lungs during fetal development, causing the lungs to become enlarged and putting pressure on the heart and surrounding organs
Fetal Center: The first step in CHAOS care
Multidisciplinary Evaluation: meet with MFM specialist, pediatric surgeon, neonatologist, and other experts who will care for your baby
Comprehensive Imaging: detailed ultrasounds and other tests when indicated to assess your baby's condition and help plan treatment
Coordinated Delivery Planning: our team works to ensure your baby receives immediate specialized care at birth
How is a CHAOS evaluated?
CHAOS is typically found during a routine pregnancy ultrasound around 20 weeks of gestation and often thought to be bilateral cystic lung lesions. When this is suspected, we recommend that you have a series of follow-up studies including:
- A comprehensive ultrasound will give us more detail and look at other body structures that may be affected.
- A fetal MRI gives us advanced images of your baby's airway and lungs, as well as details of any other suspected problems
- A fetal echocardiogram is an ultrasound of the baby’s heart that is performed by a pediatric cardiologist. This test is recommended to look at the heart structure and function.
- Other anomalies or an underlying syndrome is present in approximately 50 - 70% of cases, so you will meet with a genetic counselor who can give you more information regarding screening tests.
All of this information will help the fetal team give you the most accurate information so that you can make the best possible decision about treatment.
(pic: fetal MRI or a child with CHAOS, the small arrow depicts the area of laryngeal atresia. The large arrow shows the overexpanded lungs)
How does CHAOS affect your baby?
During normal fetal development, the lungs continuously produce fluid that flows out through the airway and helps the lungs grow and mature. In CHAOS, a partial or complete blockage of the upper airway prevents this fluid from escaping, leading to:
- The lungs becoming overexpanded - This overexpansion is one of the hallmark features seen on prenatal ultrasound.
- Pressure builds within the chest- The enlarged lungs compress nearby structures, including the heart, great vessels, and diaphragm.
- The heart is compressed and displaced- Pressure on the heart can impair normal cardiac filling and function, reducing blood flow and leading to signs of heart failure before birth.
- Fluid can accumulate in the body (hydrops fetalis) - Impaired heart function and abnormal venous return can cause fluid buildup in the abdomen, chest, skin, or around the heart. Hydrops is a sign of severe disease and worsens prognosis.
- Amniotic fluid abnormalities may occur - Compression of the esophagus can interfere with fetal swallowing, sometimes leading to polyhydramnios (excess amniotic fluid).
Despite these significant effects, oxygen delivery to the fetus before birth is usually preserved because the placenta, not the lungs, provides oxygen during pregnancy. The greatest risk occurs at delivery, when the newborn must breathe independently but cannot do so if the airway remains obstructed
What are the treatment options for CHAOS?
Prenatal management
- Close monitoring during pregnancy
- Fetal intervention (select cases) - In rare and carefully selected situations—typically when the obstruction is partial—fetoscopic procedures may be considered to create or relieve an airway opening before birth. These interventions are highly specialized and not appropriate for all cases.
- Delivery planning - at a tertiary center with pediatric airway, surgical, anesthesia, and neonatal intensive care teams present.
Delivery
- EXIT procedure (Ex Utero Intrapartum Treatment)
For most fetuses with known complete or severe airway obstruction, delivery is performed using the EXIT procedure. This allows the baby to remain attached to the placenta while the airway is secured, providing oxygen and preventing emergency airway compromise. Airway management during EXIT may include:- Direct laryngoscopy or bronchoscopy
- Endotracheal intubation
- Tracheostomy if intubation is not possible
Neonatal Intensive Care
Babies with CHAOS should be delivered at our center where an EXIT procedure can be performed to enable safe delivery with an airway. Once the airway is secured, the baby is fully delivered and transferred to the neonatal intensive care unit (NICU) for ongoing care. The neonatologist is a specially trained pediatrician that will manage your baby’s medications, feeding, and daily needs while in the NICU.
Most of these children require a specialized breathing tube called a tracheostomy connected to a machine to assist with breathing (ventilator). Some may also require medications to help maintain a normal blood pressure.
A tube placed through the mouth (oral gastric or OG) all the way to the stomach. This tube will suck out any fluid with in the stomach to prevent your baby from choking or breathing stomach contents into the lungs and to prevent the intestines from becoming too dilated with air.
Your baby will receive fluids and antibiotics through a special IV called a PICC line, initially through the umbilical cord, then placed in one of the limbs. Because the child will not be initially allowed to eat, they will also receive nutrition through the PICC line called TPN, or total parenteral nutrition. TPN contains protein, fat, sugar, vitamins, and minerals and will meet all your baby’s nutritional needs
(Pic: Neonatal care team treating a newborn with CHAOS)
Infant and Childhood care
- Definitive airway management - Many children require a tracheostomy to maintain a stable airway, either temporarily or long-term, depending on the anatomy.
- Surgical reconstruction - Selected patients may be candidates for airway reconstruction surgery (such as laryngotracheal reconstruction) later in infancy or childhood, depending on airway anatomy and overall health.
- Management of associated conditions - Treatment of coexisting cardiac, renal, craniofacial, or genetic conditions is an important part of long-term care.
(Pic: Infant with CHAOS undergoing treatment in the hospital)
Long-term support
What to expect after discharge from the hospital
When a child with CHAOS leaves the hospital, they will need long-term follow-up and support. We have a specialized multidisciplinary care clinics at Primary Children's Hospital for kids born airway and esophageal disease called the Esophageal Airway Center (EAC). Your child will follow-up frequently in this clinic and meet with multiple specialists who are experts in this care and will make sure they are growing and developing normally. Additionally, the Comprehensive Care Team/Trach Vent Clinic will help manage complex respiratory needs.
These specialists include:
- Pediatric Cardiologist
- Pediatric Complex Care
- Pediatric ENT (Ears, Throat, and Nose)
- Pediatric Gastroenterologist
- Pediatric Interventional Radiologist
- Pediatric Pulmonologist
- Pediatric Surgeon
- Dietician
- Occupational therapist
- Physical therapist
- Respiratory Therapist
- Speech therapist
(pic: Otto, the first long-time survivor of CHAOS in Utah)
To learn more about Otto and his journey, click here to visit his instagram page!
