new presentation notes for chd

8/7/2019 new presentation notes for chd

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Cyanosis

What is cyanosis and how you would identify it?

Porth, (2002:1449) says that cyanosis is a bluish discolouration,

especially to the skin and mucous membranes, caused by an excess of

deoxygenated haemoglobin in the blood.

It is important for the nurse to distinguish between cardiopulmonary and

respiratory causes ensures effective management.

Hypoxemia test can be instigated

Administer 100% high-pressured oxygen for ten minutes. If the infant

responds and its colour becomes pink then cardiopulmonary causes are

discounted (McConnell & Elixson, 2002). In addition to this, arterial

blood gases should be monitored.


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Transposition of the great vessels

The great vessels of the heart include the aorta and the pulmonary artery.

In the transposition of the great vessels the aorta and pulmonary artery are

reversed (McConnell & Elixson, 2002). Hence:

The pulmonary artery is connected to the left ventricle instead of

the right ventricle.

The aorta is connected to the right ventricle instead of the left

ventricle.

This means two things:

That unoxygenatated blood returning from the body to the heart

misses out on getting oxygenated and gets pumped directly into the

system via the aorta what would happen?

Oxygenated blood returning from the lungs gets pumped back to

the lungs again what may happen with this?

In the infant with transposition of the great arteries Reddy (2002) claim

that the closure of the patent ductus arteriosus will cause a rapid onset of

cyanosis and tachypnoea. It is an emergency. Infants with the

transposition of the great vessels will not survive unless there is another

defect in the form of a patent ductus arteriosus (Muscari).


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What is a patent ductus arteriosis?

The initial breath at birth induces the circulatory switch from placental to

pulmonary oxygenation of blood. Prior to this, blood in the foetal heartbypasses the lungs and flows across the left and right ventricles to the

systemic circulation via openings called the ductus arteriosus and the

foramen ovale (Porth, 2002:522).

Within the first 24 to 72 hours of life, the switch to pulmonary

oxygenation of blood causes these openings to close, thereby separating

the ventricles into the pulmonary and systemic circulations (Porth,

2002:524).

Emergency medical care for infants with the transposition of the great

arteries is focused on maintaining the patent ductus arteriosus by

administering intravenous Prostaglandin E.

This procedure may cause apnoea. Hence the nurse must prepare for an

intubation procedure (McConnell & Elixson, 2002).

Surgical treatment is arterial switch. Preferably performed within the

first two weeks of life. If conditions do not permit this, then an atrial

switch is performed, however, this operation has a much higher long-term

morbidity rate (Porth, 2002:528).


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Tetralogy of Fallot

The tetralogy of Fallot is the most common cyanotic heart defect (Pretre

et al., 2001).

It is a complex congenital heart disorder that consists offour linked

congenital heart defects.

These include,

A ventricular septal defect,

Right ventricular hypertrophy causing right to left shunting of

unoxygenated blood. Which leads to cyanosis and hypoxemia.

Obstruction of the pulmonary outflow channel including

pulmonary stenosis. Also leads to decreasing oxygenated blood.

An aorta overriding the ventricular defect.

What happens?

The obstruction of the pulmonary outflow and pulmonary stenosis

causes the right ventricle to work harder (Porth, 2002:527).

This leads to hypertrophy of the right ventricle.

Right to left shunting through the ventricles causes mixing of

oxygenated blood and unoxygenated blood. This causes decrease inoxygenated blood to systemic circulation.

Also decrease in pulmonary blood, which causes hypoxemia and

cyanosis (Suddaby, 2001).


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Signs and Symptoms of Tetralogy of Fallot

Infants with the tetralogy of Fallot will display some cyanosis at birth.

As pulmonary obstruction and ventricular hypertrophy increase, cyanosis

will become more severe, and they will experience hypercyanotic or tet

spells

These will be evident in the infants first months of life and continue into

childhood. Pfleiger, (2005).

What are tet spells?

Activities that increase oxygen requirements such as crying, feeding,

defaecating

Increase pulmonary vascular resistance.

Right to left shunting

Decreases pulmonary blood flow.

What signs and symptoms do we see?

Child becomes acutely cyanotic.

Hyperpneic (increase to rate of breath in proportion to rate of

metabolism)

Irritable

Diaphoretic

As spell progresses child will become limp and may lose consciousness.


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What do we do?

Place child in knee to chest position increases vascular systemic

resistance and increases pulmonary blood flow.

Older children may naturally assume these positions.

Surgical Management of Tetralogy of Fallot

Palliative surgery designed to increase pulmonary blood flow and

decrease hypoxemia. A shunt to increase pulmonary blood flow called

Blalock-Taussig shunt

Corrective surgery carried out later on in childhood is cardiopulmonary bypass and

aortic cross-clamping will be necessary.

new presentation notes for chd

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