II. Definition

  1. Pumonary Arterial Hypertension (PAH) associated acute on chronic right ventricular failure

III. Pathophysiology

  1. See Pulmonary Arterial Hypertension
  2. Uncompensated right ventricular failure results in hemodynamic collapse

IV. Risk Factors: Precipitating Factors

  1. Infectious causes
    1. Pneumonia
    2. Indwelling catheter
    3. Bowel organism transposition
      1. Intestinal barrier fails due to hypoperfusion and venous congestion
  2. Medication causes
    1. Continuous intravenous infusion pump or catheter malfunction (e.g. epoprostenol infusion)
    2. Medication non-compliance
  3. Cardiovascular causes
    1. Supraventricular Tachycardia
    2. Pulmonary Embolism
  4. Miscellaneous causes
    1. Trauma or surgery
    2. Anemia
    3. Hypoxia

V. Imaging: Echocardiogram

VI. Management: Manage underlying exacerbating factors

  1. Treat infections
  2. Correct pump or catheter dysfunction
  3. Manage Supraventricular Tachycardia
    1. Rate control is insufficient and may reduce Cardiac Output (e.g. Beta Blockers, Calcium Channel Blockers)
    2. Synchronized Cardioversion or chemical cardioversion (e.g. Amiodarone) is preferred

VII. Management: Optimize right ventricular function in PAH Crisis

  1. Supplemental Oxygen to keep Oxygen Saturation >90-92%
  2. Goal mean arterial pressure: 65 mmHg
  3. Preload optimization
    1. Volume overload (most common): Diuretics
    2. Volume deficit: Small volume bolus trials (250-500 cc)
      1. Exercise caution in Fluid Replacement
      2. Avoid excessive volume replacement
        1. Risks worsening right ventricular failure
        2. May force septum to bow into left ventricle with decreased EF
  4. Myocardial contractility optimization (inotropes)
    1. Low dose Dobutamine (<5 mcg/kg/min)
      1. Improves myocardial contracility (beta-1 agonist and inotrope) and decreases Afterload
      2. Avoid Dobutamine at doses above 5 mcg/kg/min due to risk of tachyarrhythmia
    2. Norepinephrine (or Epinephrine is preferred by many)
      1. Indicated in hypotensive patients prior to Dobutamine (or if Hypotension occurs after Dobutamine started)
      2. Avoid in normotensive PAH due to risk of increased pulmonary artery pressure
  5. Right Ventricular Afterload optimization
    1. Epoprostenol IV
      1. Risk of vasodilation and Hypotension
      2. Avoid even brief interruptions once started (short half-life) with decompensation risk
      3. Epoprostenol may also be delivered by inhalation (50 mcg/kg/min) including with Ventilator
    2. Inhaled Nitric Oxide in the intubated patient
      1. Advantages: No systemic effects and improves V-Q mismatch
      2. Risk of rebound, severe Pulmonary Arterial Hypertension if abruptly stopped

VIII. Management: Mechanical Ventilation

  1. Avoid intubation and Mechanical Ventilation if possible
    1. Mechanical Ventilation increases right Ventricular Preload and Afterload
    2. Highest risk with higher Tidal Volume and PEEP
  2. Rapid Sequence Intubation
    1. Ketamine may be preferred induction agent
  3. Ventilator settings
    1. Reduce Tidal Volume, PEEP and plateau pressure to lowest level that will maintain oxygenation and ventilation
    2. Titrate up FIO2 to prevent Hypoxia
    3. Avoid hypoventilation and secondary hypercapnia (increases pulmonary artery pressure)

IX. References

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