Congenital diaphragmatic hernia
What is congenital diaphragmatic hernia?
Congenital diaphragmatic (dye-ah-fra-mat-ick) hernia is an opening in the diaphragm, which is the muscle separating the chest from the abdomen (see illustration at right). This hole allows the contents that would normally be in the abdomen to push up into the chest cavity. The lungs may be underdeveloped (hypoplastic ) because they lack the space to grow. CDH can have an effect on both lungs even though the defect is only on one side.
If the amount of abdominal contents pushed into the chest is significant enough, the heart will be pushed out of its normal position in the middle of the chest. This shift may also reduce the amount of space for the lung on the opposite side, leading to abnormal growth and development of that lung.
About the defect
Diaphragmatic hernia occurs in about 1 in 2,400 live births. The hole occurs 90 percent of the time on the left side. The defect in the diaphragm can range from a very small hole with only a loop of bowel protruding through it to a severe defect in which no diaphragm or only minimal diaphragm is present.
If the hole is large enough to allow the liver and intestines into the chest, the repair may require a prosthetic patch. This type of CDH has a poorer prognosis. There are two less serious types that involve either a small hole with only a loop of bowel through or a hole through which the abdominal contents seem to "slide" in and out of the chest cavity. These two types have a much better prognosis.
Are there other birth defects involved?
Diaphragmatic hernia may be associated with other birth defects. As many as 50 percent of newborns who have CDH will have an associated anomaly of the central nervous system , cardiovascular , skeletal , gastrointestinal or genitourinary system.
What causes CDH?
We do not know what causes diaphragmatic hernia. We do know it is not related to anything the mother ate or did during pregnancy.
Prenatal diagnosis of congenital diaphragmatic hernia
Doctors may diagnose a diaphragmatic hernia during a routine ultrasound . The heart may have shifted to the opposite side of the chest, and intestinal loops may be in the chest. Other anomalies can look similar. If your doctor suspects CDH, he or she will refer you to a maternal-fetal medicine specialist (a doctor who handles high-risk pregnancies). Your maternal-fetal medicine specialist may perform other tests to confirm the diagnosis or to gain information about the baby’s prognosis for you before delivery.
How does the diagnosis of congenital diaphragmatic hernia affect the pregnancy?
It’s likely that your maternal-fetal medicine specialist will recommend a number of tests and monitoring. These could include:
- Targeted ultrasound: You will need to have a targeted ultrasound to evaluate your baby for other associated anomalies.
- Amniocentesis with chromosomal analysis: Your doctor likely will offer amniocentesis with chromosomal analysis because congenital diaphragmatic hernia has a high incidence of associated chromosomal anomalies.
- Fetal echocardiogram: You also may need to have fetal echocardiogram . CDH has a 16 percent incidence of an associated congenital heart defect. Because of the position of the heart with CDH (often shifted to the right when the hernia is located on the left), this evaluation may be difficult to perform. Therefore, your doctor may need to repeat the procedure more than one time.
- Fetal movement counting: Close observation of your baby as the pregnancy progresses may include an ultrasound every two to four weeks to evaluate fetal growth and amniotic fluid volume. At approximately 26 weeks, we will instruct you about daily fetal movement counting .
- Non-stress tests: You may begin to have non-stress tests at approximately 32 weeks gestation. They will be twice weekly.
- Biophysical profile: Your doctor may recommend a biophysical profile (BPP) be done weekly. BPP is an ultrasound study that monitors:&
- Amniotic fluid volume
- Your baby's breathing movements
- Movements of the extremities along with non-stress test results
- Fetal MRI: Your doctor may recommend a fetal MRI (magnetic resonance imaging study) if there is concern that the fetus has a more severe form of CDH. This does not involve any radiation so it is safe for both you and your baby. This may offer more accurate information about the severity of the CDH so you may be better prepared about what to expect when your baby is born.
Possible pregnancy complications
Some women will suffer from polyhydramnios with their pregnancy. Polyhydramnios is an increased amount of amniotic fluid. This condition puts the mother at risk for preterm labor and delivery, and the baby at risk for health issues related to prematurity. The lungs are one of the last organs to mature, so a baby born prematurely will have lungs that are not fully matured. Immature lungs will further compromise the ability to effectively exchange gases.
Cesarean section delivery is not necessary for a baby with CDH. A Cesarean delivery would only be performed for other reasons, which will be discussed by your obstetrician or maternal-fetal medicine specialist.
Delivery at a special hospital
We recommend that your baby be born at a hospital with a Level III or IV neonatal intensive care unit, and where there are neonatologists, pediatric cardiologists and a pediatric general surgeons on staff. In addition, the hospital should have the ability to provide ECMO (extra corporeal membrane oxygenation), which is a form of heart and lung bypass that may help your baby if he or she is very sick. This is so your baby can be cared for immediately after delivery by health care professionals who are familiar with the care of a baby with diaphragmatic hernia in a setting where all of the necessary resources are readily available.
Knowing that your baby has CDH allows you to plan for the delivery at a hospital that can provide the best care in a timely manner. This may mean you will be delivering some distance from home. If you live locally, we will await spontaneous labor. If you do not live locally, we may schedule induction close to your due date.
How does congenital diaphragmatic hernia affect my baby?
At birth, the diaphragmatic hernia can have serious effects on your baby's ability to breathe. CDH also may affect your baby’s blood circulation due to pressure and shifting of the position of the heart as well as abnormal development of the lungs and their blood vessels. If the diaphragmatic hernia is large, or there is a significant amount of intestines and other abdominal organs within the chest cavity, the lung on the side of the defect, as well as the opposite side may be affected.
If the diaphragmatic hernia is smaller in size, with a lesser amount of intestines within the chest cavity, the lungs may not be as significantly affected. Although the prenatal ultrasound and fetal MRI are used to try to predict how severe your baby’s condition will be, it’s hard to predict exactly how sick your baby will be after birth.
Most babies with a diaphragmatic hernia will need immediate interventions after delivery. If your baby has CDH, it’s best if he or she is born at a hospital that can care for you and your baby. This keeps the two of you together and avoids the trauma of having to transport your baby after birth.
How do you treat congenital diaphragmatic hernia?
At birth, most babies with CDH will need help to breathe. We will pass a tube into your baby's airway to help with breathing. This tube passes through the vocal cords, so while it is in place, your baby will not be able to make sounds.
We will pass another tube through your baby's mouth and into the stomach. This is to keep the stomach decompressed, or small in size, so it does not press more on the lungs.
Once your baby is delivered, we will quickly assess him or her. If at all possible, we will allow you and your partner to see and hold your baby. When necessary, we will transfer your baby to the NICU for further treatment.
Typically the umbilical cord has two arteries and a vein. We will place a special tube called an umbilical venous catheter (UVC) in the vein in your baby’s umbilical cord so we can give nourishment (vitamins, minerals, calories, fat) and medication for a prolonged period of time.
We also will place an arterial line called an umbilical artery catheter (UAC) in one of the arteries of the umbilical cord. We use this line to give IV fluid, remove blood for testing and monitor blood pressure.
Some medications your baby may need before surgery include:
- Narcotics to keep your baby free from pain
- Paralytics to keep your baby from moving
- Blood pressure medication to maintain an adequate blood pressure or decrease abnormally high blood pressure in the heart and lungs
Complications and therapies
There are two potential problems we need to deal with regarding the lungs. First, we will evaluate the lungs for size and ability to oxygenate the body. Lungs that are smaller than normal are hypoplastic. This condition is called pulmonary hypoplasia. This means the lungs are underdeveloped and may not have enough volume to sustain life. Another concern is pulmonary hypertension (high blood pressure within the lungs). We will also monitor the degree to which your baby can take in oxygen and remove carbon dioxide through their lungs.
Pulmonary hypertension is an increased pressure in the arteries that brings blood to the lungs. This increased pressure pushes blood away from the lungs and decreases the supply of oxygen to the body. This shunting of blood away from the lungs is normal while the baby is inside the uterus because the baby is not breathing on his/her own. However, once a baby is born, these arteries in the lungs need to relax so that blood can flow through the lungs and exchange gases. These gases are exchanged when the blood gets rid of carbon dioxide and picks up oxygen to supply the body. Pulmonary hypertension is a life-threatening complication. If the oxygen levels are low, we may attempt some more aggressive treatment options, including nitric oxide therapy and a heart-bypass machine.
Nitric oxide therapy
During nitric oxide therapy, the oxygen content supplied to the baby is enhanced with a gas called nitric oxide, which is delivered directly into the breathing tube that is used to deliver oxygen to your baby. Nitric oxide relaxes the pulmonary blood vessels and lowers pulmonary blood pressure. By supplying nitric oxide directly into the lungs, the blood vessels in the lungs relax, but the blood vessels in the body do not. This lowers the blood pressure in the lungs, but not the blood pressure in the other organs of the body. Blood is able to circulate through the lungs and pick up oxygen and rid itself of carbon dioxide. Unfortunately, nitric oxide treatment works more effectively in babies with pulmonary hypertension from other causes and does not work as well with CDH. However, we often use it to see if it helps your baby when he or she is sick and has severe high blood pressure in the lungs.
ECMO, or extra corporeal membrane oxygenation, is a type of heart-lung bypass. ECMO is used when other treatment options fail. While on ECMO, the heart and lungs are able to rest because the machine does their work. This rest sometimes allows time for resolution of pulmonary hypertension. A baby only can stay on ECMO for a brief time, usually 3 to 21 days. A surgical procedure to place cannulas (large tubing) into the blood vessels in the neck is performed at the bedside. A vein in the neck is used to take the unoxygenated blood out of the body. This blood is run through the ECMO machine, which puts oxygen into the blood, and that oxygenated blood is returned to the body through an artery in your baby's neck. Heparin, a blood thinner, is put into the blood to keep it from clotting. Babies on ECMO are cared for in the Pediatric Intensive Care Unit.
ECMO treatment has risks. The major risk is bleeding. Because of the need to use heparin to thin the blood, there is a risk for bleeding in various parts of the body. The most serious is when bleeding occurs in the brain. Other potential complications can include infection and mechanical failure. An ECMO specialist will be at the bedside at all times to ensure that the system is functioning properly. If your baby is so sick that he or she requires ECMO, the long-term outlook may include neurologic deficits due to a period of time when he or she was not getting enough oxygen to the brain. These deficits can range from mild mental handicaps and/or chronic lung disease (similar to asthma) to more severe problems such as cerebral palsy and vision and hearing problems. If a decision about whether to use ECMO is needed, the doctors will discuss with you the pros and cons of the treatment.
When will surgery take place?
Doctors will close the diaphragm if and when your baby is well enough to undergo surgery. You may need to make some difficult decisions during this time.
What happens after surgery?
After surgery your baby will need continued assistance to breathe effectively. He or she will need frequent lab work to monitor oxygenation, electrolytes and blood counts.
After surgery your baby may need a variety of medications including:
- Antibiotics to fight infection
- Pain medication to control pain after surgery
- Blood pressure medication to stabilize and maintain an adequate blood pressure
- Sedation to keep your baby calm
- Paralytics to keep your baby from moving
Your baby may look puffy or swollen after surgery. He or she will not be able to eat until his or her condition has stabilized. But we will provide nourishment through the IV fluids.
Because infants with this condition cannot eat for a prolonged period of time, we will supply special nourishment through a central line. Total parenteral nutrition is an IV solution that contains protein, fats, sugar, vitamins and minerals. This will supply your baby with all his/her nutritional requirements until he or she is able to take food by mouth.
Before starting feedings by mouth, we wait for signs from your baby that the bowels are beginning to work. These signs include bowel sounds, spontaneous passage of stool and a decrease in the amount of drainage coming from the tube in your baby's stomach. We typically start feedings through the tube that is in your baby's stomach. The amount we begin with is very small, and we gradually increase it as we see that your baby is tolerating the food. In those babies who need to be fed through a tube, our goal is to eventually transition to feedings by mouth if your infant is able to do so.
Will I be able to help care for my baby?
Yes. Please ask your baby's nurse about ways to interact with and care for your baby.
If you had planned to breastfeed your baby, you can begin to pump your breasts while you are still in the hospital and we encourage you to do so, as breast milk is often the best form of nutrition for your baby. A lactation consultant can answer your questions. Your milk will be frozen and stored in the NICU until your baby is ready for it. The NICU has breast pumps and private rooms available to you when you are visiting.
When can my baby go home?
Your baby will go home when he or she can eat enough to gain weight and his or her lung function is adequate to oxygenate the body.
The amount of time babies with a diaphragmatic hernia spend in the NICU varies greatly depending on their course of care and the severity of the problem. An average length of stay is 6 to 12 weeks. Your baby likely will go home on anti-reflux medication, as all babies with CDH have some degree of gastroesophageal reflux.
What is my baby's long-term prognosis?
Long-term issues include chronic lung disease and gastroesophageal reflux. Babies with CDH will be assessed for developmental delays due to prolonged hospitalization and ventilation requirements.
For those who do not need ECMO, the survival rate is approximately 90 percent. If your baby requires ECMO, the survival rate decreases to about 50 percent.