Anesthesia for Congenital Heart Disease

Anesthesia for Congenital Heart Disease - Shifty Shunts & Cycles

• Shunts: Dynamic blood flow.
  • L→R (Acyanotic: VSD, ASD, PDA): ↑PBF. Risk: Eisenmenger.
  • R→L (Cyanotic: ToF, TGA): ↓PBF, systemic desat. Risk: paradoxical air embolism.
• PVR vs. SVR Balance: Key for shunt direction/magnitude. Anesthetics alter this.
  • Goal: Optimize Qp/Qs.
• Neonatal Circulation: Initially high PVR; PVR ↓ post-birth.

  ⭐ In R→L shunts, inhalation induction is slower; IV induction faster.

• 📌 Shunt Control: FiO2, PEEP, CO2, vasoactive drugs.

Anesthesia for Congenital Heart Disease - Tiny Hearts, Big Checks

• Core Goals: Maintain cardiac output, oxygen delivery; balance Qp:Qs (pulmonary/systemic flow).
• Shunt Physiology:
  • L→R (VSD, ASD): Risk pulmonary overcirculation. Faster inhalational induction. Avoid ↓SVR.
  • R→L (TOF, TGA): Risk hypoxia. Slower inhalational, faster IV induction. Maintain SVR. 📌 Right-to-Left = Rapid IV.
• Key Concerns: Pulmonary hypertension (PHTN) - avoid ↑PVR (hypoxia, acidosis). Single ventricle - delicate balance.
• Monitoring: Pre/post-ductal SpO2, arterial line, CVP.

⭐ For Tetralogy of Fallot (TOF) "tet spells": ↑SVR (phenylephrine), ↓PVR (O2, morphine), sedation, β-blockers.

Anesthesia for Congenital Heart Disease - Delicate Drug Dance

• Primary Goals: Maintain cardiac output (CO), tissue oxygenation. Crucially, balance Pulmonary (PVR) & Systemic Vascular Resistance (SVR).
• Induction Agents:
  • Ketamine: Preferred for stability; ↑SVR, ↑HR, maintains CO.
  • Etomidate: Hemodynamically stable.
  • Avoid/Caution Propofol: ↓SVR, myocardial depression.
• Maintenance Agents:
  • Volatiles (Sevoflurane, Isoflurane): Dose-dependent ↓SVR; minimal myocardial depression.
  • Nitrous Oxide (N₂O): ↑PVR; avoid in R→L shunts, pulmonary hypertension (PHTN).
  • Opioids (Fentanyl, Remifentanil): Hemodynamic stability, blunt stress.
• PVR/SVR Modulation:

⭐ In Tetralogy of Fallot (TOF) with a cyanotic "Tet spell," immediate goals are to ↑SVR (e.g., phenylephrine IV) and ↓PVR (e.g., 100% O₂, morphine, correct acidosis). 📌 Knee-chest position is a key non-pharmacological maneuver.

Anesthesia for Congenital Heart Disease - Lesion Anesthesia Keys

• General: Maintain CO & O2 delivery. De-air IV lines (esp. R→L shunts).
• L→R Shunts (VSD, ASD, PDA):
  • Goal: Avoid ↑shunt. Maintain SVR. Avoid significant ↓PVR.
• Tetralogy of Fallot (TOF) (R→L Shunt):
  • Goal: Maintain SVR (critical!), ↓PVR, contractility.
  • "Tet Spell": From ↑PVR / ↓SVR.
  • 📌 Management: MOCK (Morphine, Oxygen, Knee-chest, Ketamine or β-blocker, Phenylephrine).
• Transposition of Great Arteries (TGA):
  • Goal: Maintain PDA (PGE1). Balance Qp:Qs. Avoid ↑PVR.
• Coarctation of Aorta:
  • Goal: Control proximal HTN, ensure distal perfusion.
• Single Ventricle (Fontan):
  • Goal: Low PVR, adequate preload, contractility. Spontaneous ventilation.

⭐ For TOF, maintaining SVR is crucial; ↓SVR (e.g., vasodilators) worsens R→L shunt, risking a "Tet" spell.

High‑Yield Points - ⚡ Biggest Takeaways

• Shunt direction impacts drug delivery: L-R shunts slow IV induction; R-L shunts speed gas induction, ↑ paradoxical air embolism risk.
• Manage TOF "tet spells" by ↑SVR (e.g., phenylephrine), ↓PVR (e.g., O2, avoid crying), and providing sedation.
• Maintain ductal patency in duct-dependent lesions with continuous PGE1 infusion.
• Single ventricle physiology (e.g., Fontan) requires meticulous balancing of SVR/PVR; avoid factors that ↑PVR.
• Sevoflurane is often preferred for inhalational induction; ketamine generally maintains cardiovascular stability.
• Crucial: meticulous IV line de-airing (especially with R-L shunts) and appropriate endocarditis prophylaxis for high-risk patients.