Difficulty with feeding
Failure to thrive
Episodes of bluish pale skin during crying or feeding
(ie, "Tet" spells)
Exertional dyspnea, usually worsening with age
Squatting during excercise
Most infants are smaller than expected for age
A systolic thrill is usually present anteriorly along the left sternal
A harsh systolic ejection murmur (SEM) is heard over the
pulmonic area and left sternal border
During cyanotic episodes, murmurs may disappear
Cyanotic (Tet) spells
Acute hypoxemic attacks represent a true emergency
Usually, the underlying diagnosis is tetralogy of Fallot.
In a Tet spell,
increase in obstruction to pulmonary blood flow (either in heart or in
if systemic perfusion is reduced, as with hypovolemia or the development of
Clinical presentation and diagnosis
They are characterised by:
Period of uncontrollable crying / panic,
Rapid and deep breathing (hyperpnoea),
Deepening of cyanosis,
Decreased intensity of heart murmur,
Limpness, convulsions and rarely, death.
common in the early morning
Prolonged agitation and crying
Exercise, bathing, or fever
In such cases(tet spells), the absence of a heart
murmur is a worrisome indicator that pulmonary
blood flow is severely compromised
Hemoglobin and hematocrit values are usually elevated in proportion to
the degree of cyanosis. Prolonged cyanosis causes reactive polycythemia
that increases the oxygen-carrying capacity. While in cyanosis due to
Anemia hb is 3-5g/dl
results show varying oxygen saturation, but pH and partial pressure of
carbon dioxide (pCO2) are normal, unless the patient is in extremis, such
as during a tet spell.
Oximetry is particularly useful in a dark-skinned patient or an anemic
patient whose level of cyanosis is not apparent. Generally, cyanosis is not
evident until 3-5 g/dL of reduced hemoglobin is present.
Management is directed at manipulating the relative resistances of the
systemic and pulmonary
vascular beds, as well as maintenance of appropriate circulating volume
and heart rate
1. Knee-to-chest / Squatting:
2. Oxygen (100%) can be administered which also increases systemic
resistance and may help enhance oxygen delivery
but usually has minimal effect.
3. Morphine: 0.1-0.2 mg/kg IM. (Caution in infants under 3 months).
morphine may cause pulmonary vasodilatation and decreases vantilatory drive
If the above procedures are ineffective or have suboptimal effect, the following
treatments may need to be given.
4. Crystalloid or colloid fluid bolus: 10-20ml/kg by rapid IV push.
give an IV fluid bolus of 20 mL/kg normal saline
Sodium bicarbonate, 1–2 mEq/kg slowly IV
5. . phenylephrine
If cyanosis persists, give phenylephrine (10 mcg/kg by slow IV push)
to pharmacologically increase the systemic vascular resistance
5. beta blocker (e.g. propranolol or esmolol)
In severe episodes, propranolol (Inderal) may be given
Esmolol 500 mcg/kg over one minute IV, then maintenance of 50
mcg/kg/min can be increased in steps of 50mcg/kg/min to maximum dose of
beta blocker, reduces dynamic muscular stenosis of the right ventricular
outflow tract and increasing pulmonary blood flow
. Progressive hypoxemia and the occurrence of cyanotic spells are
indications for early surgery.