Glossary of Childhood Onset Heart Disease
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Surgical
Complications
Chylothorax
Chylothorax is the accumulation of chyle in the pleural (lung) space. Chyle is usually a milky fluid comprised of lymph drainage, which carries fat, protein and white blood cells (lymphocytes). It occurs after injury to or obstruction of the thoracic duct. Injury to the thoracic duct during cardiovascular surgery occurs because of its proximity to the great vessels (aorta and pulmonary artery) in the chest, where the duct crosses from right to left. Most cases of chylothorax after surgery for congenital heart disease have occurred after non-open heart procedures, mainly subclavian-pulmonary artery shunt procedures, resection of coarctation of the aorta, and ligation of patent ductus arteriosus.
Symptoms of chylothorax are related to the amount of fluid present and the rate at which it accumulates and may include fatigue, shortness of breath at rest or on exertion, heaviness, and discomfort on the affected side. An initial trial of conservative therapy is indicated, since spontaneous closure can occur. Removing chyle from the pleural space is best accomplished by chest tube placement for continuing draining. This allows full re-expansion of the lung, which closes the lymph connection (fistula) by the lung’s compression effects. In order to maintain adequate nutrition while reducing lymph flow, it is recommended that the diet be changed to limit the fat source to medium-chain triglycerides (fats that are directly absorbed from the gut into the blood stream without having to go through the lymph system). Alternatively, the patient may need to take nothing by mouth and receive total parenteral nutrition (TPN) by receiving all nutrition through an IV or central line for many weeks.Since flow of chyle is minimized only when the gastrointestinal tract is completely at rest, others prefer to stop oral feedings altogether. The drainage of chyle usually slows or stops within 7 days after tube drainage and with changing of the diet to reduce lymph flow. If this does not occur, more aggressive action such as surgery may be recommended.
Horner’s Syndrome
Cardiovascular surgery is the most common cause of acquired Horner syndrome in children. This syndrome consists of drooping of the upper eyelid, miosis (contraction of the pupil of the eye) and anhidosis (lack of sweating of the surrounding forehead). The presumed causes include trauma at the time of surgery associated with placing one of the tubes for cardiopulmonary bypass (heart-lung machine), stretching of nerve roots due to positioning, trauma from cauterization, nerve compression at susceptible sites, and traction on nerves. Most deficits, if they are to resolve, will do so in 6 to 8 weeks. Transient Horner's syndrome has been seen in young children, particularly after difficult jugular vein cannulation in small infants.
Nosocomial Infections
Fortunately, important wound complications are uncommon after cardiac surgery. Nosocomial bacterial infections are hospital acquired infections. Blood infection, infection inside or around the heart, particularly when prothetic valves and materials have been used, is a major threat to the patient’s life. Therefore, prophylactic antibiotic therapy is recommended for cardiac operations.
Intravascular devices (central venous catheters and arterial catheters, pacemakers) predispose to bloodstream infections by forming a bridge between the external environment and the bloodstream. Most device-related infections are caused by skin organisms (Staphylococcus and Streptococcus, and Candida (a fungus) infecting the catheter tip at the time of insertion, or growing down along the insertion track. Prolonged mechanical ventilation after operation also increases the risk of infection. All intravascular and endotracheal devices should be removed as early postoperatively as possible for many reasons, including minimizing the risk of infection.
Methicillin-resistant Staph Aureus (MRSA) infections are particularly problematic. MRSA strains are not more virulent (aggressive) than methicillin-sensitive strains, but the former may be more difficult to treat because of multiple antibiotic resistance and resulting limited therapeutic drug choices. Patients infected or colonized with MRSA should be managed with contact precautions for the duration of illness because the carriage of the organism usually persists for weeks to months.
Pleural effusions
Pleural effusions are fluid collections in the space surrounding the lungs. These are very common following cardiovascular surgery. The fluid collections are usually bloody in the immediate postoperative period becoming serous (tissue fluid) with time. The collections are usually transient, resolving on their own. Persistent effusions, either one-sided or both sides may be associated with excessive fluid within the body, heart failure, chylothorax, infection or inflammation. Persistent effusions are not uncommon following Fontan or hemi-Fontan procedures. This occurs because of the higher central venous pressures in the large veins in the chest that results following these operations.
Post-perfusion ("capillary leak") Syndrome
A generalized inflammatory response following cardiopulmonary bypass, typically occurring in newborns and young infants. This results in generalized swelling (edema), low urine output, and worsening deterioration of the heart musclefunction.
Postpericardiotomy syndrome
A febrile illness with inflammation of the pericardium (the sac in which the heart is located and protected in the chest) and pleura (lining surrounding the lung). Fluid accumulation may occur in the pericardial sac and around the lung one week or more following surgery in which the pericardium is opened. Accompanying the fever may be tiredness, lack of energy, abdominal pain, respiratory distress and poor appetite. Some patients do not appear ill; other children are irritable; but a few are desperately sick, especially if the fever is high or if there is enough fluid around the heart to compromise its function (tamponade). Echocardiography is diagnostic. Bed rest and anti-inflammatory drugs are beneficial. Emergency pericardiocentesis (draining the fluid from around the heart) may be life saving.
Stroke
A sudden decrease or stopping of blood flow in an artery of the brain sufficient to cause damage to the brain tissue. These occur infrequently following cardiopulmonary bypass (open heart operations) and most likely result from obstruction of a small blood vessel or blood vessels by clots or debris, or from air embolization. Children and young adults with persistent cyanosis (right to left shunting through atrial or ventricular septal defects) are at continued higher risk from embolism from intravenous catheters.
- Other Articles in This Section
- Associated Conditions
- Cath Lab Procedures
- Imaging Techniques
- Medical Personnel /Services
- New Strategies / Techniques
- Surgical Complications
- Surgical Procedures
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