Tetralogy of Fallot
Paroxysmal hypercyanotic attacks (hypoxic, “blue,” or“tet” spells)
A reduction of an already compromised pulmonary blood flow > severe systemic hypoxia > metabolic acidosis
Infants who are only mildly cyanotic at rest more prone and less tolerant of hypoxic spells because they are not as polycythemic
Usually in morning or after vigorous crying
Spells may last from a few minutes to a few hours
Decrease in intensity of the EJECTION systolic murmur as right ventricular outflow diminishes
↑RR, agitated > cyanosis > gasping > syncope > convulsions > hemiparesis
If resolve quickly, followed by generalised weakness and sleep
Rx
A reduction of an already compromised pulmonary blood flow > severe systemic hypoxia > metabolic acidosis
Infants who are only mildly cyanotic at rest more prone and less tolerant of hypoxic spells because they are not as polycythemic
Usually in morning or after vigorous crying
Spells may last from a few minutes to a few hours
Decrease in intensity of the EJECTION systolic murmur as right ventricular outflow diminishes
↑RR, agitated > cyanosis > gasping > syncope > convulsions > hemiparesis
If resolve quickly, followed by generalised weakness and sleep
Rx
- place prone in the knee-chest position
- oxygen
- SC morphine max 0.2 mg/kg
- if no response check pH and correct HCO3
- intubation and sedation
- intravenous phenylephrine (↑SVR > ↑R outflow ↓R>L shunt
- β-Adrenergic blockade by the intravenous administration of propranolol (0.1 mg/kg given slowly to a maximum of 0.2 mg/kg)