RT Book, Section A1 Doherty, Gerard M. SR Print(0) ID 58102325 T1 Tetralogy of Fallot T2 Quick Answers Surgery YR 2010 FD 2010 PB The McGraw-Hill Companies PP New York, NY SN LK accesssurgery.mhmedical.com/content.aspx?aid=58102325 RD 2024/10/10 AB • A congenital heart lesion that decreases pulmonary arterial blood flow resulting in a right-to-left shunt• Cyanosis and decreased oxygen delivery causes compensatory polycythemia (Hct > 70%) and spontaneous thrombosis• Exercise, acidosis, pain worsens cyanosis, can cause hypoxic spells• Squatting increases systemic resistance, causing increased pulmonary flow and oxygen saturation• β-Blockers (decreases spasm), fluid intake, HCO3 administration, norepinephrine (increases systemic resistance) may help decrease hypoxia• Clubbing due to proliferation of capillaries and AV fistulas in extremities• Bronchial and mediastinal arteries enlarge• Ductus arteriosus maintains flow to lungs during fetal development• Alprostadil early can allow time for optimization before definitive treatment• 4 anomalies: 1. Ventricular septal defect (VSD)2. Pulmonary stenosis or atresia3. Overriding aorta4. RV hypertrophy• Pulmonary stenosis may involve infundibulum, valve, or main pulmonary artery (PA)• Extent of pulmonary atresia/stenosis has wide spectrum of severity• Pulmonary flow depends on aortopulmonary collaterals, can be extensive enough to cause congestive heart failure• Spasm of infundibular muscle may cause unconciousness and death