Yesterday’s Times UK reported about a healthy 10 month old child in Spain who would have died in utero if he had not had surgery while still in utero. Surgery was done to relieve an upper airway obstruction. He is said to be the first healthy child in the world to be born after this procedure.

Congenital High Airway Obstruction Syndrome

During development of an embryo portions of the amniotic fluid are produced and exhaled by the lungs. If there is a blockage of the airway at any level, fluid from the lungs can back up. This will cause massively enlarged lungs, a flattened diaphragm and a dilated tracheobronchial tree. This will result in – in utero heart failure (non-immune hydrops).

Causes
The airway obstruction in CHAOS may be due to:
The absence of or blockage of the larynx
The absence of or blockage of the trachea
A cyst which blocks the airway

Diagnosis:
CHAOS is a rare condition detected by ultrasound as a complete or nearly complete obstruction of the upper airway.
The lungs appear extremely large. The diaphragm may be inverted and the heart compressed.
The heart may appear elongated with its chambers compressed by the enlarged large lungs.
The tracheobronchial tubes may be dilated and the fetus may have abnormal breathing movements.
Although a fetus diagnosed with Congenital High Airway Obstruction Syndrome (associated with hydrops) is unlikely to survive without fetal intervention, in some cases the hydrops resolves and the fetus can survive.

Management of CHAOS
The mother should have a detailed ultrasound to detect associated abnormalities. A fetal echocardiogram will detect structural heart disease. A prenatal karyotype will confirm chromosomal abnormalities.
The fetus should be followed closely for early signs of hydrops (in utero heart failure). The parents will want to consult with a medical geneticist and a pediatric surgeon to plan for delivery at a tertiary-care hospital that has expertise and experience in the EXIT (ex utero intrapartum treatment) procedure.

Fetal Interventions for CHAOS
Fetal intervention for CHAOS depends upon the gestational age at diagnosis and the presence or absence of hydrops. In rare cases, less than 30 weeks gestation, where there is complete obstruction and the fetus is at significant risk for intrauterine death, open fetal surgery may be attempted. After 30 weeks gestation, an EXIT procedure may also be performed in order to obtain an airway at the time of delivery.

In the case that was reported in the Times yesterday, it was noted, that the foetus had a complete obstruction at the larynx and was unlikely to survive without surgery in utero. At 21 weeks gestation, through a needle puncture on the mother’s abdomen, an endoscope was introduced through the mouth of the foetus. It was directed to the obstructed trachea and the membrane blocking it perforated through a laser. A healthy child was born some weeks later with no respiratory problems. The doctors treating the child in Barcelona said that this was the first successful procedure in the world for the condition where a healthy baby was delivered.