CDH Terminology
Prenatal and Diagnostic Terms
Amniocentesis (“Am-nee-oh-sen-tee-sis”): When CDH is diagnosed or suspected during pregnancy, an amniocentesis is often recommended to either diagnose or eliminate the possibility of genetic disorders. During this procedure, a small amount of amniotic fluid, which contains genetic information from the fetus, is taken from the uterus and tested. This procedure typically happens in the OB office setting under ultrasound guidance and is considered a very safe procedure with a low chance of risk to the mother or the fetus.*+*
Polyhydramnios (“Paul-lee-hi-dram-nee-ohs”): Polyhydramnios refers to the presence of excessive amniotic fluid. While it only occurs in 1-2% of all pregnancies, it is somewhat more common in CDH pregnancies because the esophagus may be compressed as organs are shifted in the chest cavity. Mild polyhydramnios often goes away on its own and is unnoticed by the mother, while more severe cases may cause discomfort, shortness of breath, and extra weight gain. Patients with polyhydramnios need to be more closely monitored during late pregnancy to prevent preterm labor.*
O/E (observed over expected or observed divided by expected): The ratio of what is seen divided by what the typical size/weight/amount is. O/E lung volume is used to describe the difference between the observed amount of lung volume shown during prenatal imaging, like fetal MRI, and the lung volume typical for healthy lungs at the same developmental stage.
LHR (lung-to-head-ratio): This measurement is often provided after a fetal MRI and is sometimes used to categorize the severity of the hernia. This measurement is a ratio of the observed lung volume and the observed head circumference. This ratio of observed LHR is often compared to an expected LHR (O/E LHR). A higher LHR may be associated with a milder CDH.
Surgical Terms
FETO (fetoscopic tracheal occlusion): FETO is an experimental in-utero procedure that is typically only offered in instances of severe CDH. During FETO, a scope is inserted into the mother’s abdomen and through the uterine wall and amniotic sac into the fetus’ mouth, where a small balloon is inserted into the trachea. The balloon is inflated, blocking the trachea. Normally a fetus’s lungs produce fluid that escapes through the trachea (windpipe). Blocking the trachea prevents this fluid from escaping, increasing pressure in the trachea. Research has shown that building up this tracheal pressure and fluid content can stimulate lung growth. The FETO procedure provides an artificial way to block your baby’s trachea and promote lung development. The balloon remains in place for a prescribed amount of time, after which the balloon is removed.*+*
Repair Surgery: Repair surgery is a procedure to correct the congenital disorder after a CDH baby is born. During a repair surgery, the surgeon operates on the infant to correct any displacement of organs by moving them back into the abdominal cavity and repairing or replacing the missing diaphragm. For a smaller defect in the diaphragm, it may be possible to sew the existing diaphragm muscle to itself, closing the hole. For larger defects, a patch is used to create an artificial diaphragm.*
GORE-TEX patch: GORE-TEX is a durable biomedical material used by surgeons to create a patch to replace the missing diaphragm.*
Feeding Tubes: Sometimes CDH babies have difficulty with eating and need some extra support.
Gastrostomy tubes (G-tubes) are short tubes that are surgically placed to go through the abdominal wall, straight into the stomach. They are often attached to longer tubes for continual or periodic feeding via a feeding pump or syringe.
Nasogastric (NG) tubes are thin, flexible tubes inserted through the nose into the stomach.
Nasojejunal (NJ) tubes are similar to an NG tube but bypass the stomach and go straight into the small bowel.
Orojejunal (OJ) tubes and orogastric (OG) tubes function similarly but are inserted into the mouth rather than the nose.
Jejunostomy tubes (J tubes) are surgically placed directly into the small intestine. The tube is usually a red rubber tube that is stitched at the stoma site. This type of tube doesn't have a balloon or mushroom end to hold it in place, so it can come out easily.*
Pulmonary Terms
Hypoplastic Lung: A small, underdeveloped lung. In CDH patients, the lung on the side of the defect is often considered hypoplastic.
Pulmonary Hypertension (PH): PH refers to high blood pressure in the arteries to the lungs and the right side of the heart. This means that the heart and lung systems must work harder to carry oxygenated blood through the body. If PH occurs, it must be treated because this extra effort by the heart over time can cause it to become weak and fail.
PO2 (partial pressure of oxygen): In the hospital, practitioners often run tests on a patient's blood gasses. PO2 refers to the amount of dissolved oxygen in the blood and shows how well the lungs bring oxygen into the bloodstream*.
pCO2 (partial pressure of carbon dioxide): pCO2 is another measure found when testing blood gasses and refers to the amount of carbon dioxide dissolved in the blood. This shows practitioners how well the body is eliminating CO2 during respiration*.
Oxygen Saturation (Sats or SO2): An external measurement taken with a pulse oximeter placed on the hand or foot which shows the percentage of hemoglobin that is carrying oxygen in the blood. The care team often sets goals for each patient, but typical healthy readings are between 95-100% in children and adults. “Desaturation” is when these numbers read low, signifying oxygen loss*.
Respiratory Support
High flow and low flow oxygen: Oxygen delivery systems are categorized as high flow or low flow. High flow systems deliver oxygen while also providing a higher measure of pressure to help inflate the lungs. Low flow systems deliver oxygen without the added pressure flow. Mechanical ventilation, tracheostomy systems, CPAP, and BiPAP are all examples of high flow systems, while the typical example of low flow oxygen is a small nasal cannula attached to an oxygen tank or oxygen concentrator, which delivers oxygen at a low, continual rate without added pressure.
ECMO (extracorporeal membrane oxygenation): ECMO support refers to heart-lung bypass, meaning that the ECMO machine takes over either cardiac function, lung function, or both, ensuring these vital functions are maintained while the body is weakened and trying to heal. While on ECMO, blood flows out of the body into the ECMO machine and is oxygenated, warmed, and medicated as necessary, and then flows back into the body*.
Endotracheal (ET) tube: An ET tube is a small, flexible tube inserted through the mouth down to the trachea, or windpipe, creating an artificial airway. The process of inserting an ET tube is called “intubation,” and its removal is “extubation.” A patient must have an ET tube inserted to receive many types of respiratory support*.
Ventilator: Mechanical ventilation via a ventilator takes over breathing for a patient via an endotracheal tube, which is inserted into the mouth and down to the trachea, while the other end is connected to the ventilator. The ventilator blows oxygen into the lungs and CO2 out for the patient. Frequently, the patient will be sedated to allow the body to rest while the machine does that work.
Oscillator (HFOV, high-frequency oscillatory ventilation): HFOV is another type of mechanical ventilation that sends in oxygen in smaller, faster amounts than traditional ventilation and is used as a strategy to protect the lungs of the patient. The oscillator keeps the lungs perpetually inflated rather than inflated and deflated at rhythmic intervals like traditional ventilation.*
Jet Ventilation: High-frequency jet ventilation (HFJV) significantly differs from HFOV. This machine provides short jets of gas to help the baby breathe in and then lets them breathe out on their own. The amount that is inhaled vs. exhaled is adjustable, which can be helpful in cases of patients with high CO2 levels. It is used in conjunction with traditional mechanical ventilation.*
Tracheostomy (or tracheotomy): A tracheostomy is a procedure wherein a hole is surgically created in the neck that allows a tracheostomy tube to be inserted into the trachea so that mechanical breaths can be delivered to the patient. Commonly known as “trachs” (pronounced “trakes”), tracheostomies are typically performed for people who need longer-term mechanical ventilation.*
CPAP (Continuous Positive Airway Pressure): A type of respiratory support given through a nasal cannula or sealed mask that delivers oxygen at a constant pressure rate. CPAP is used when a patient doesn’t require the higher forms of support, like an ET (endotracheal) tube, but needs positive pressure into the airway to be artificially regulated, which makes the breathing process easier.*
BiPAP (Bi-level Positive Airway Pressure): Very similar to CPAP, except that when the patient takes a breath, a BiPAP machine delivers two levels of air pressure to the patient, whereas CPAP does not vary the amount of pressure provided.*
Nitric Oxide: A gas that is naturally produced by the body and helps relax the blood vessels. Occasionally, more of this gas is required to help the patient better ventilate than what the body is naturally producing. The gas is given directly into the lungs via the breathing circuit of the ventilator.*
Hospital Life:
Rounds: During rounds, the medical team visits each patient in the hospital to review the patient’s status and care plan. Any changes for the day are typically communicated during rounds, and this is a great opportunity for parents to voice concerns or questions about treatment. Rounds typically happen in the morning and again in the evening after hospital staff shift changes.*
Arterial line: Arterial lines are thin tubes inserted into an artery for easier retrieval of arterial blood for testing, which may be needed up to a few times per day. In CDH babies, an umbilical arterial line or umbilical artery catheter (UAC) is commonly used, where a line is placed through the belly button into an umbilical artery.*
Central line: A central venous line is a long, soft, flexible tube placed into a large vein, which allows for the easy administration of fluids, blood, or medications to a patient. Unlike IV lines, central lines can stay in for an extended period of time, making them very helpful during longer inpatient stays. Central lines are consistently checked for any signs of irritation or infection, and the dressings are changed regularly. Central lines are also checked periodically for “patency” to ensure they are still unobstructed.*
PICC line (peripherally inserted central catheter): This is a type of central line wherein a long, thin tube is inserted through a peripheral vein (in the arm or leg) into the larger veins closer to the heart, which allows for fewer needle sticks and less irritation in the smaller veins. In infants, this is typically through the leg or ankle, as the arms and wrists are frequently too small.*
Foley catheter: A foley urinary catheter is a tube placed into the bladder to drain a patient’s urine.*
Chest tube: A chest tube is a small plastic tube inserted into the chest and used to drain any extra fluid accumulated in the space between the lungs and the chest wall (the pleural space). Chest tubes can be used to drain fluids passively or via a suction catheter.*
Wound Vacuum: A wound vacuum is sometimes used to help wounds heal faster by applying a vacuum to assist in closing the wound and decrease the air pressure on it.
EEG (electroencephalogram): An EEG is a test that measures electrical activity in the brain. If any kind of seizure activity is suspected or observed in a patient, an EEG might be ordered to identify seizures and assist in their treatment.*
NIRS (Near Infra-Red Spectroscopy): NIRS (pronounced “neers”) use small sensors placed on the body, often on the forehead and lower back, to monitor tissue oxygen saturation and perfusion to the brain and kidneys. This makes sure that these crucial organs are receiving and using enough oxygen.
Common Medications Types:
Nutrition: In some instances, especially during early hospitalization, infants might require nutrition to be delivered intravenously rather than through the digestive system. TPN, total parenteral nutrition, is an example of a formula created specifically for the patient’s dietary needs, along with lipids (added fats).*
Diuretics: Diuretics are commonly used in respiratory patients to remove excess fluids that can develop due to chronic lung disease. Examples: Lasix (furosemide), Diuril (Chlorothiazide)
Sedatives and pain management: Medications may be used for sedation and pain management, particularly after surgeries and/or while on ECMO. Examples: Sedatives - Versed (midazolam); narcotics - fentanyl or morphine; analgesics - acetaminophen
Antibiotics: Used in case of or to prevent a bacterial infection. If an infection is present, bacterial cultures may be taken to help the care team target the specific type of infection. Examples: Amoxycillin, gentamicin, erythromycin, Cephalexin
Blood Products: Especially while on ECMO or during surgeries, a patient may need supplemental donated blood, platelets, or plasma. Please talk to your doctor early if you have religious concerns about this.
Anticoagulants: Anticoagulants are used to help thin the blood, particularly in patients on ECMO, to prevent blood clots. Example: heparin
Vasodilators: Vasodilators are used to help open (dilate) blood vessels, allowing for blood to more easily pass through and oxygenate the body. Examples: Sildenafil, Minoxidil
Antacids: In patients with acid reflux, antacids may be used to help neutralize the stomach acid, decreasing pain associated with reflux. Examples: Prevacid (lansoprazole), Prilosec (omeprazole), Protonix (pantoprazole)