What is the management approach post Norwood operation?

Post-Norwood Operation Management

The management of patients after Norwood operation requires meticulous attention to maintaining the appropriate balance between systemic and pulmonary blood flow through careful monitoring of hemodynamic parameters and timely interventions to optimize circulation and prevent complications. 1

Immediate Postoperative Management

Hemodynamic Monitoring and Optimization

• Monitor key parameters continuously:

  • Systolic, diastolic, and mean blood pressure
  • Central venous pressure
  • Arterial and venous oxygen saturation
  • Lactate levels
  • Urine output 1

• Maintain appropriate pulmonary-to-systemic blood flow ratio (Qp:Qs):

  • Target Qp:Qs of 1:1 to avoid pulmonary overcirculation or systemic hypoperfusion
  • Adjust inspired oxygen fraction (initially 100%, then taper)
  • Consider inhaled nitric oxide (20 ppm initially, then taper) 2

Medication Management

• Vasodilator therapy:

  • Nitroglycerin (2-4 μg/kg/min) to reduce pulmonary vascular resistance
  • Chlorpromazine as a systemic and pulmonary vasodilator 2
  • Afterload reduction to improve cardiac output, especially in patients with diminished myocardial function 3

• Inotropic support:

  • Milrinone for inotropy and afterload reduction
  • Epinephrine or dopamine for additional inotropic support as needed 3

Respiratory Management

• Initial ventilation with high FiO2 (100%) and inhaled nitric oxide (20 ppm)
• Gradual weaning of inspired oxygen and nitric oxide as arterial oxygen saturation improves
• Target extubation by postoperative day 2-6 2, 4
• Careful monitoring for respiratory complications

Monitoring for Complications

Shunt-Related Complications

• Assess for shunt stenosis or thrombosis:

  • Sudden desaturation
  • Metabolic acidosis
  • Hemodynamic instability 5

• Management of stenotic right ventricle-pulmonary artery (RV-PA) shunt:

  • If stenosis is identified, removal of the stenotic RV-PA shunt and conversion to an optimal modified Blalock-Taussig shunt is preferred over adding a second shunt 6

Other Complications

• Monitor for retrograde aortic arch obstruction which can compromise coronary blood flow 5
• Assess for neoaortic dilation and potential aortic valve insufficiency 5
• Watch for signs of coronary ischemia, particularly important as coronary arteries arise from a small aortic root 5

Standardized Approach

• Implementation of a standardized clinical guideline for perioperative management has been shown to:
  • Decrease variability in care
  • Reduce hours of postoperative mechanical ventilation
  • Shorten cardiac ICU length of stay
  • Increase successful extubation by postoperative day 2
  • Decrease reintubation rates 4

Long-term Considerations

• Prepare for subsequent staged surgeries:

  • Bidirectional cavopulmonary anastomosis (Glenn procedure) typically around 6 months of age
  • Fontan procedure typically at 2-4 years of age 5

• Monitor for long-term sequelae specific to Norwood repair:

  • Aortic obstruction related to anastomosis of pulmonary artery and aorta
  • Neoaortic dilation
  • Coronary ischemia 5

Pitfalls to Avoid

• "Hands-off" approach in patients with preoperative diminished myocardial function - these patients benefit from afterload reduction and inotropic support similar to traditional Norwood management 3
• Pulmonary overcirculation which can lead to systemic hypoperfusion and decreased oxygen delivery 6
• Inadequate monitoring of the balance between systemic and pulmonary circulation, which can rapidly deteriorate in these fragile patients 1