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Pulmonary Arterial Hypertension Crisis

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Pulmonary Arterial Hypertension Crisis, Pulmonary Hypertension Crisis, Acute Pulmonary Hypertension Management, PAH Crisis, Acute Right Ventricular Failure Management

  • See Also
  1. Pulmonary Arterial Hypertension
  2. Pulmonary Hypertension
  3. Pulmonary Hypertension Causes
  4. Pulmonary Hypertension Diagnosis
  5. Pulmonary Hypertension Management
  • Definitions
  1. Pulmonary Arterial Hypertension Crisis
    1. Pumonary Arterial Hypertension (PAH) associated acute on chronic Right Ventricular Failure
  • Pathophysiology
  1. See Pulmonary Arterial Hypertension
  2. Uncompensated Right Ventricular Failure results in hemodynamic collapse
    1. Causes of Right Heart Failure
      1. Pulmonary Arterial Hypertension (as described here)
      2. Decreased contractility (right ventricular Myocardial Infarction or Myocarditis)
      3. Volume overload (e.g. Excessive volume Resuscitation as in multisystem Trauma, Sepsis)
    2. Right Ventricular Failure spiral of death (regardless of cause)
      1. Right Ventricular Afterload (pulmonary artery pressure) increases
      2. Decreases right ventricular coronary pressure (esp. in systole) and results in RV ischemia
      3. Decreases right ventricular ejection fraction
      4. Increases right ventricular volume
      5. Interventricular Septum shifts left, reducing left ventricular volume and cardiac ouput
      6. Decreases mean arterial pressure and further decreases right ventricular pefusion
  • Risk Factors
  • Precipitating and Predisposing Factors
  1. Infectious causes
    1. Pneumonia
    2. Indwelling catheter
    3. Sepsis
    4. 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 and factors
    1. Trauma or surgery
    2. Anemia
    3. Tricuspid Regurgitation
    4. Hypoxia
    5. Obesity
    6. Chronic lung disease
  1. See Pulmonary Hypertension
  2. Decreased Cardiac Output
  3. Increased Right Ventricular Filling Pressures
  4. Right ventricle chamber size may appear larger than left ventricle with septal deviation left
    1. Right ventricular findings may be dynamic, worsening quickly with decompensation
    2. What appears initially to be a normal right ventricle, may rapidly dilate with reduced contractility
  • 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
  4. Correct factors that exacerbate pulmonary artery pressure (to decrease pulmonary vascular resistance)
    1. Hypoxia
    2. Hypercarbia
    3. Acidosis
  1. Supplemental Oxygen to keep Oxygen Saturation >90-92%
    1. Correcting Hypoxia reduces pulmonary vascular constriction, lowering right sided pressures
  2. Goal mean arterial pressure: >65 mmHg
    1. Optimize fluid balance (e.g. Diuretics, unless volume depleted)
    2. Critical to maintain systemic Blood Pressure much higher than pulmonary artery pressure (e.g. Vasopressors)
  3. Preload optimization
    1. Volume overload (most common): Diuretics (e.g. Furosemide IV)
    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. Vasopressors to increase Systemic Vascular Resistance (SVR)
    1. Goal
      1. Increase Systemic Vascular Resistance (SVR) without increasing pulmonary vascular resistance (PVR)
      2. Maintains SVR higher than PVR gradient, maintaing right heart perfusion throughout diastole AND systole
      3. Avoid in normotensive PAH due to risk of increased pulmonary artery pressure
    2. Preferred agents that primarily increase SVR (more than PVR)
      1. Vasopressin 0.01 to 0.04 units/min
      2. Low dose Epinephrine
        1. Consider in combination with Vasopressin at doses starting as low as 0.02 mcg/kg/min
      3. Low dose Norepinephrine
        1. May be used at low dose instead of Epinephrine in combination with Vasopressin
    3. Avoid inotropes that significantly increase pulmonary artery pressure
      1. Avoid Phenylephrine
      2. Avoid Dopamine
  5. Myocardial contractility optimization (inotropes)
    1. Precautions
      1. Inotropes such as Milrinone and Dobutamine are best deferred to intensivists once invasive monitoring available
      2. Aside from Epinephrine and norephinephrine, inotropic effects (e.g. Milrinone, Dobutamine) are long lasting
        1. Once given, the inotropic effects are not easily reversed and may have profound adverse effects
    2. Milrinone
    3. Levosimendan
    4. 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
      3. Use Vasopressor in hypotensive patients prior to Dobutamine (or if Hypotension occurs after Dobutamine started)
    5. Epinephrine, and Norepinephrine to lesser extent, are also inotropes
  6. Right Ventricular Afterload optimization (decrease pulmonary vascular resistance)
    1. General
      1. These agents may exacerbate Left Ventricular Failure
      2. Consider in submassive or massive Pulmonary Embolism with acute Pulmonary Hypertension
    2. Epoprostenol
      1. Inhalation with nebulizer or Ventilator (50 mcg/kg/min)
        1. Local effects reduce lung pressures without significant Hypotension risk
      2. Intravenous: 0.05 mcg/kg/min IV
        1. Risk of vasodilation and Hypotension
        2. Avoid even brief interruptions once started (short Half-Life) with decompensation risk
    3. Inhaled Nitric Oxide (20 ppm)
      1. Advantages: No systemic effects and improves V-Q mismatch
      2. Risk of rebound, severe Pulmonary Arterial Hypertension if abruptly stopped
    4. Alternatives when nitric oxide or epoprostenol are not available (see Crager lecture reference below)
      1. Nitroglycerin 1 mg/ml inhaled/nebulized 5 mg (5 ml) over 15 minutes OR
      2. Milrinone 1 mg/ml inhaled/nebulized 5 mg (5 ml) over 15 minutes
      3. https://emcrit.org/pulmcrit/ntg/#:~:text=Nitroglycerin%20is%20metabolized%20into%20nitric,intubated%20patients%20and%20intubated%20patients.
  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
    2. RSI in Pulmonary Hypertension Crisis is high risk for Cardiac Arrest
  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)
  • Resources
  1. Scott Weingart. EMCrit 272 – Right Heart Failure with Sara Crager. EMCrit Blog. Published 4/29/20. Accessed 8/22/20.
    1. https://emcrit.org/emcrit/right-heart-sara-crager/
  • References
  1. Kobner and Crager (2024) EM:Rap, 3/18/2024
  2. Meter (2013) Crit Dec Emerg Med 27(5): 2-10
  3. Orman, Greenwood and Swaminathan in Herbert (2016) EM:Rap 16(10): 9-11
  4. Galie (2009) Eur Heart J 30(20): 2493-537 [PubMed]
  5. Greenwold (2015) Emerg Med Clin North Am 33(3): 623-43 +PMID:26226870 [PubMed]
  6. Hoeper (2011) Am J Respir Crit Care Med 184(10): 1114-24 [PubMed]