Palliative care in transposition of great vessels

Associate Editors-In-Chief: Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]; Atif Mohammad, M.D., Priyamvada Singh, MBBS

Palliative



Palliative treatment is normally administered prior to corrective surgery in order to reduce the symptoms of TGA (and any other complications), giving the newborn or infant a better chance of surviving the surgery. Treatment may include any combination of:


 * Echocardiogram
 * Chest x-ray
 * Magnetic resonance imaging (MRI)
 * Computed tomography (CT) scan

Each type of medical imaging has its merits and drawbacks, so they are usually used in combination to provide as complete a model as possible from which to plan and prepare for the corrective surgery. Medical imaging may also be used to monitor how well the heart is functioning, or to determine whether a treatment is having the desired effect. [edit] Surgery [edit] Minor


 * Cardiac catheterization
 * Rashkind balloon atrial septostomy
 * Balloon angioplasty
 * Endovascular stenting
 * Angiography

Cardiac catheterization is a minimally invasive procedure which provides a means of performing a number of other procedures.

A balloon atrial septostomy is performed with a balloon catheter, which is inserted into a foramen ovale, PFO, or ASD and inflated to enlarge the opening in the atrial septum; this creates a shunt which allows a larger amount of red blood to enter the systemic circulation.

Angioplasty also requires a balloon catheter, which is used to stretch open a stenotic vessel; this relieves restricted blood flow, which could otherwise lead to CHF.

An endovascular stent is sometimes placed in a stenotic vessel immediately following a balloon angioplasty to maintain the widened passage.

Angiography involves using the catheter to release a contrast medium into the chambers and/or vessels of the heart; this process facilitates examining the flow of blood through the chambers during an echocardiogram, or shows the vessels clearly on a chest x-ray, MRI, or CT scan - this is of particular importance, as the coronary arteries must be carefully examined and "mapped out" prior to the corrective surgery.

It is commonplace for any of these palliations to be performed on a TGA patient.

Moderate


 * Left anterior thoracotomy
 * Isolated pulmonary artery banding (PAB)
 * Left lateral thoracotomy
 * PAB (when coarctation or aortic arch repair also required)
 * Right lateral thoracotomy
 * Blalock-Hanlon atrial septectomy

Each of these procedures is performed through an incision between the ribs and visualized by echocardiogram; these are far less common than heart cath procedures.

Pulmonary artery banding is used in a small number of cases of d-TGA, usually when the corrective surgery needs to be delayed, to create an artificial stenosis in order to control pulmonary blood pressure; PAB involves placing a band around the pulmonary trunk, this band can then be quickly and easily adjusted when necessary.

An atrial septectomy is the surgical removal of the atrial septum; this is performed when a foramen ovale, PFO, or ASD are not present and additional shunting is required to raise the oxygen saturation of the blood. [edit] Major


 * Median sternotomy
 * PAB (when intracardiac procedures also required)
 * Concomitant atrial septectomy

In recent years, it is quite rare for palliative procedures to be done via median sternotomy. However, if a sternotomy is required for a different procedure, in most cases all procedures that are immediately required will be performed at the same time. [edit] Monitoring and maintenance Palliated pre-operative d-TGA + VSD neonate. Palliated pre-operative d-TGA + VSD neonate.


 * Nasogastric tube (NG tube or simply NG)
 * Intubation, oxygen mask, or nasal cannula
 * Intravenous drip (IV)
 * Arterial line
 * Central venous catheter
 * Fingerprick
 * Sphygmomanometer
 * Pulse oximeter
 * EKG

An NG tube is used to deliver nourishment, and occasionally medication, to the patient. Since the tube extends right into the stomach, it can also be used to monitor how well the patient is digesting their "food". Paediatric units normally provide facilities and equipment for mothers of infant patients to pump their breastmilk, which can then be fed to the infant through the NG tube, and/or stored for later use.

Oxygen therapy is commonplace for hospitalized d-TGA patients. This may range from an oxygen mask resting on the bed nearby their head to intubation. In some cases, patients are intubated as a precaution; the machine can monitor breathing and supplement the patient as much or as little as they need.

IV's are used to deliver medication, blood products, or other fluids to the patient. Arterial lines provide a constant monitor of blood pressure, as well as a method of obtaining samples for blood gas tests; central lines can also monitor blood pressure and provide blood samples, as well as provide a means to deliver medication and nourishment; fingerpricks (or heelpricks on small babies) are used to obtain blood samples for certain tests.

A sphygmomanometer may be used for intermittent blood pressure monitoring even if a patient is being otherwise monitored using a central or arterial line.

A pulse oximeter is attached to a finger or toe and provides constant or intermittent monitoring of the blood's oxygen saturation level.

An EKG creates a visual readout of how well the heart is functioning. [edit] Medication


 * Prostaglandin (PGE)
 * Antibiotics
 * Diuretics
 * Analgesics
 * Cardiac glycosides
 * Sedatives

When PGE is administered to a newborn, it prevents the ductus arteriosus from closing, therefore providing an additional shunt through which to provide the systemic circulation with a higher level of oxygen.

Antibiotics may be administered preventively. However, due to the physical strain caused by uncorrected d-TGA, as well as the potential for introduction of bacteria via arterial and central lines, infection is not uncommon in pre-operative patients.

Diuretics aid in flushing excess fluid from the body, thereby easing strain on the heart.

Analgesics normally are not used pre-operatively, but they may be used in certain cases. They are occasionally used partially for their sedative effects.

Cardiac glycosides are used to maintain proper heart rhythm while increasing the strength of each contraction.

Sedatives may be used palliatively to prevent a young child from thrashing about or pulling out any of their lines. [edit]