What is the management approach for a patient experiencing a pulmonary hypertensive crisis?

Management of Pulmonary Hypertensive Crisis

For patients experiencing a pulmonary hypertensive crisis, immediately admit to ICU and initiate inhaled nitric oxide as first-line pulmonary vasodilator, add dobutamine for inotropic support, and escalate to continuous IV epoprostenol if the patient fails to stabilize—while maintaining oxygen saturation >90% and avoiding mechanical ventilation whenever possible. 1, 2

Immediate Recognition and ICU Admission

A pulmonary hypertensive crisis is characterized by high heart rate, low systolic blood pressure, low urine output, and rising lactate levels, indicating imminent right ventricular failure. 1 The mortality rate for PAH patients admitted to ICU reaches 41%, making early recognition and aggressive intervention critical. 1

All patients with suspected pulmonary hypertensive crisis require immediate ICU admission with continuous hemodynamic monitoring. 1, 2

Pharmacologic Management Algorithm

First-Line Therapy: Inhaled Nitric Oxide

Initiate inhaled nitric oxide immediately as the preferred first-line pulmonary vasodilator. 1, 2 Inhaled nitric oxide decreases pulmonary vascular resistance, improves cardiac output, has a short half-life, and does not affect systemic vascular resistance. 2, 3

Second-Line Therapy: Inotropic Support

Start dobutamine as the preferred inotrope for all hypotensive PAH crisis patients, as it has neutral or beneficial effects on pulmonary vascular resistance. 1, 2 Dobutamine is often preferred over milrinone due to its shorter half-life when there is risk of hypotension. 2

Alternative inotropes with acceptable pulmonary vascular effects include milrinone and epinephrine. 2

Third-Line Therapy: IV Epoprostenol

If the patient fails to stabilize on inhaled nitric oxide and dobutamine, initiate continuous IV epoprostenol. 1, 3 Epoprostenol is the only therapy for PAH that has been shown to prolong survival and is the preferred treatment option for the most critically ill patients. 3

Dosing protocol for IV epoprostenol: 4

• Start at 2 ng/kg/min
• Increase in increments of 2 ng/kg/min every 15 minutes or longer until dose-limiting pharmacologic effects are elicited
• If symptoms persist after initial stabilization, increase by 1-2 ng/kg/min increments at intervals of at least 15 minutes

Epoprostenol must be administered by continuous intravenous infusion via a central venous catheter using an ambulatory infusion pump. 4

Vasopressor Support

Consider vasopressin to offset potential drops in systemic vascular resistance, particularly in septic or liver patients with pulmonary hypertension, as vasopressin deficiency is common in these populations. 2 Maintaining systemic vascular resistance greater than pulmonary vascular resistance is critical to prevent right ventricular ischemia. 2

Alternative Pulmonary Vasodilators

If inhaled nitric oxide is unavailable, consider aerosolized prostacyclin or analogue (such as iloprost) to reduce pulmonary vascular resistance. 3 If neither inhaled agent is available, an IV bolus of prostacyclin may be considered. 3

Respiratory Management

Oxygenation

Maintain oxygen saturation >90% at all times to prevent hypoxia-induced increases in pulmonary vascular resistance. 3, 1, 2 Patients with borderline oxygen saturations may require 3-4 L per minute of supplemental oxygen. 3

Mechanical Ventilation

Avoid mechanical ventilation if possible, as positive intrathoracic pressure reduces venous return and worsens right ventricular failure. 1, 2 If ventilation becomes necessary:

• Employ a low tidal volume strategy (approximately 6 mL/kg lean body weight) 1, 2
• Keep peak pressures <30 cmH₂O 2
• Limit positive end-expiratory pressure to ≤10 cmH₂O when possible 2
• Avoid permissive hypercapnia as acidosis can acutely increase pulmonary vascular resistance 2

Fluid Management

Optimize fluid balance with IV diuretics for symptomatic management of right ventricular volume overload. 3 Volume overload worsens right ventricular function. 1, 2

Avoid aggressive volume expansion in patients with right ventricular failure, as this may worsen right ventricular function. 1, 2 In hypotensive patients, vasopressors and inotropes rather than fluid boluses are required to augment cardiac output and reduce the risk of exacerbating right ventricular ischemia. 5

Hemodynamic Monitoring

Direct measurement of central venous pressure via central line placement is necessary, as non-invasive estimates may be misleading. 2 Consider pulmonary arterial catheterization for accurate hemodynamic assessment in patients not responding to initial therapy. 2

Continuously monitor the systemic-to-pulmonary vascular resistance ratio, as maintaining systemic vascular resistance greater than pulmonary vascular resistance is crucial. 2

Mechanical Circulatory Support

For patients with pulmonary hypertensive crisis, low cardiac output, or right ventricular failure despite optimal medical therapy, initiate veno-arterial ECMO as a bridge to recovery or transplantation. 1, 2 Veno-venous ECMO has also been successfully used to permit dose titration of pulmonary vasodilator therapy in unstable patients. 6

Supportive Therapy

Maintain oral anticoagulation with warfarin in patients with idiopathic PAH (target INR 1.5-2.5 in North American centers or 2.0-3.0 in European centers). 1 However, note the potential inhibitory effects of prostanoid drugs on platelet function. 3

Ensure current immunization against influenza and pneumococcal pneumonia, as respiratory infections can be devastating in these patients. 3, 1

Critical Pitfalls to Avoid

Never abruptly lower the dose or withdraw epoprostenol dosing, as this can precipitate acute decompensation. 4 All dosing initiation and changes should be closely monitored. 4

Avoid oversedation during procedures, as this can lead to ventilatory insufficiency and precipitate clinical deterioration. 3

Do not use beta-blockers in patients with PAH, as they may worsen right ventricular function. 7

Avoid non-selective systemic vasodilators that may cause systemic hypotension without reducing pulmonary pressure. 7

The combination of riociguat and PDE-5 inhibitors (such as sildenafil) is contraindicated due to the risk of hypotension. 7

Caution with laparoscopic procedures using carbon dioxide for abdominal insufflation, as absorption can produce hypercarbia, which is a pulmonary vasoconstrictor. 3

Avoid non-essential surgery, and when surgery is necessary, care should be provided at a pulmonary hypertension center using a multidisciplinary approach including cardiovascular anesthesiology with careful monitoring of clinical status, oxygenation, and hemodynamics postoperatively. 3

Transition and Long-Term Management

Upon weaning from inhaled nitric oxide, start or restart a phosphodiesterase inhibitor (such as sildenafil or tadalafil) as replacement therapy to prevent rebound pulmonary hypertension. 2

For longer-term management after crisis stabilization, consider PAH-specific targeted therapies including phosphodiesterase-5 inhibitors, endothelin receptor antagonists, or prostacyclin pathway agonists. 2

Lung transplantation is an option for selected patients who progress despite optimal medical management. 3