NurseSavvy Cheat SheetDisease
Cyanotic Heart Defects
Pathophysiology & Risk Factors
Cyanotic defects shunt blood right-to-left (or mix it), so deoxygenated blood bypasses the lungs and enters systemic circulation, producing central cyanosis. Acyanotic defects shunt left-to-right, overloading the lungs and causing heart-failure signs instead. The 5 T's are the classic cyanotic lesions; Tetralogy of Fallot is the most common.
Cyanotic vs acyanotic congenital heart defects
CyanoticAcyanotic
Shunt directionRight-to-left or mixingLeft-to-right
HallmarkCentral cyanosis, tet spells, clubbingCHF signs, lung overload
Classic lesions5 T's: ToF, TGA, truncus, tricuspid atresia, TAPVRVSD, ASD, PDA, coarctation
Response to O2Cyanosis does not correctNot the issue
Cyanotic
- Shunt direction
- Right-to-left or mixing
- Hallmark
- Central cyanosis, tet spells, clubbing
- Classic lesions
- 5 T's: ToF, TGA, truncus, tricuspid atresia, TAPVR
- Response to O2
- Cyanosis does not correct
Acyanotic
- Shunt direction
- Left-to-right
- Hallmark
- CHF signs, lung overload
- Classic lesions
- VSD, ASD, PDA, coarctation
- Response to O2
- Not the issue
Signs & Symptoms
Late / SevereProgresses →
instinctive squatting
older child; raises SVRdigital clubbing
chronic hypoxiaOther findings
central cyanosis Hallmark
lips and mucous membranes, oxygen-unresponsivehypercyanotic tet spell Hallmark
ToF; sudden deep cyanosis, agitation, hyperpneaspell triggered by feeding, crying, or straining
softer murmur during spell
paradox: less pulmonary flow = worsecontinuous cyanosis from birth
suggests TGA rather than ToFDiagnostics & Labs
cyanosis unresponsive to supplemental oxygen Hallmark
points to structural shunt, not respiratoryelevated hemoglobin and hematocrit
compensatory polycythemia from chronic hypoxiapulse oximetry screening below 95%
critical CHD screen>3% SpO2 difference right hand vs foot
echocardiogram
Interventions & Priorities
Tet spell rescue sequence
- Knee-to-chest positionfirst; raises SVR
- Calm, minimize stimulation
- Supplemental oxygen
- IV morphine as prescribed
- IV fluids + phenylephrineif refractory
Treatments & Medications
prostaglandin E1 infusion Hallmark
TGA; keeps PDA open for mixing until repairarterial switch operation
TGA; within first 2 weeks of lifesurgical ToF repair
closes VSD, relieves RV outflow obstructionmorphine
tet spell pharmacologic therapyPatient Teaching
give prescribed stool softeners
straining triggers tet spellsmaintain adequate hydration
dehydration worsens polycythemia hyperviscosityavoid fluid restriction
avoid iron supplementation
worsens polycythemia and thromboembolic riskallow self-limited activity
do not strictly immobilize the childComplications
polycythemia and hyperviscosity
thromboembolic riskjunctional ectopic tachycardia
post-ToF-repair; low cardiac outputsurgical heart block
post-VSD-closure bradycardiaReport Nowescalate immediately
hypercyanotic tet spell Hallmark
knee-to-chest, calm, O2; emergencycyanosis unresponsive to oxygen in newborn
think TGA needing prostaglandin E1junctional ectopic tachycardia after ToF repairjunctional rate ~210-220 bpm
life-threatening, can cause hemodynamic collapsepostoperative bradycardia with poor perfusionHR ~46 bpm, cap refill >3 s, UOP <0.5 mL/kg/hr
surgical heart block; low cardiac output emergencyClinical Pearl
Blue baby + oxygen doesn't help = think structural. Knee-to-chest is your tet spell rescue: it's the squat the toddler already knows to do.