How do you induce anesthesia in patients with pulmonary hypertension?

Anesthetic Induction in Patients with Pulmonary Hypertension

Patients with pulmonary hypertension should undergo anesthesia induction at a specialized pulmonary hypertension center with a multidisciplinary team including pulmonary hypertension specialists, cardiac anesthesiologists, and surgeons to minimize mortality risk. 1

Pre-induction Preparation

• Optimize PAH-specific therapy before any surgical intervention 1
• Continue all PAH-specific medications perioperatively without interruption 1
• Consider arterial line placement before induction for continuous hemodynamic monitoring 1
• Ensure availability of pulmonary vasodilators (inhaled nitric oxide, prostacyclins) 2
• Have vasopressors and inotropes immediately available 1

Anesthetic Induction Technique

1. Avoid rapid sequence induction if possible due to sympathetic stimulation
2. Consider awake fiberoptic intubation to minimize sympathetic stimulation and maintain spontaneous ventilation 1, 2
3. Use cardiac anesthesiologist for intubation when possible 1
4. Choose induction agents carefully:
   • Etomidate: Preferred for hemodynamic stability
   • Ketamine: Use with caution (may increase pulmonary vascular resistance)
   • Propofol: Use reduced doses with careful titration to avoid systemic hypotension
   • Avoid high-dose opioids that may cause respiratory depression

Critical Physiologic Parameters to Maintain

• Oxygenation: Keep SpO₂ >91% to prevent hypoxic pulmonary vasoconstriction 1, 2
• Ventilation: Avoid hypercarbia and acidosis which increase PVR 1, 2
• Hemodynamics: Maintain systemic blood pressure above pulmonary artery pressure 2
• Temperature: Prevent hypothermia which increases PVR 3

Ventilation Strategy Post-Intubation

• Use low tidal volume ventilation (6-8 mL/kg) 1, 2
• Keep peak pressures <30 cmH₂O 1
• Limit PEEP to ≤10 cmH₂O if oxygenation allows 1
• Avoid permissive hypercapnia 1

Management of Hemodynamic Instability

• First-line: Inhaled nitric oxide (iNO) at 20 ppm for selective pulmonary vasodilation 1, 2
• Second-line: Inhaled prostacyclins (iloprost) if iNO unavailable 3, 4
• For RV support: Dobutamine (first-line inotrope) 2, 4
• For systemic hypotension: Consider vasopressin rather than norepinephrine 2, 5
• Avoid: Excessive fluid administration which may worsen RV function 5

Common Pitfalls and How to Avoid Them

• Oversedation: Can lead to ventilatory insufficiency and hemodynamic collapse 1
• Excessive positive pressure: Can increase RV afterload and precipitate RV failure 1
• Inadequate monitoring: Always use invasive arterial monitoring; consider pulmonary artery catheter in severe cases 4
• Abrupt withdrawal of PAH medications: Continue all PAH-specific therapies perioperatively 1
• Inadequate post-induction monitoring: Continue close monitoring for at least 24 hours post-procedure 1

Special Considerations

• For laparoscopic procedures, minimize CO₂ insufflation pressure and duration as absorbed CO₂ can increase PVR 1
• Be aware that prostanoid drugs may affect platelet function 1
• Have anticholinergic agents readily available to treat bradycardia, as patients with PAH are prone to vasovagal events 1

Remember that induction of anesthesia in patients with pulmonary hypertension carries significant risk of mortality due to right ventricular failure. The key principle is to avoid increases in pulmonary vascular resistance while maintaining adequate systemic vascular resistance and right ventricular function.