Pulmonary Hypertensive Crisis

Originally published at Pediatric EM Morsels on January 4, 2018. Reposted with permission.

Follow Dr. Sean M. Fox on twitter @PedEMMorsels


Caring for children can be rather challenging. Yes, there is a fair amount of finding ways to avoid saying “It’s Just a Virus” while conveying the fact that the child is doing just fine; however, there are also a number of children who require overt Critical Care. We have previously discussed critical presentations involving hypertension (ex, Hypertensive CrisisEclampsiaPheochromocytomaThyroid Storm), but there is another that involves the lungs that we need to add to the library. Let’s review Pulmonary Hypertensive Crisis:

 

Pulmonary Hypertension

  • Pulmonary Hypertension is not a specific disease.
  • It is the clinical picture of: [Del Pizzo, 2016]
    • Decreased pulmonary vasculature function
    • Elevated right ventricle pressure
    • Can progress to right heart failure.
  • Largely results from one or more of the following: [Del Pizzo, 2016]
    • Interruption of pulmonary vasculature maturation
      • Adult number of alveoli don’t develop until ~ 4years of age.
      • ex, congenital diaphragmatic hernia
    • Lung destruction from inflammation
    • Vasodilator/vasoconstrictor imbalance
  • Can be associated by numerous conditions and factors: [Del Pizzo, 2016]
    • Examples:
      • Acquired and Congenital heart disease
      • Respiratory distress syndrome of the newborn
      • Pulmonary veno-occlusive disease
      • Hypoxia
      • Cystic fibrosis
      • Hypercoagulable states (ex, Nephrotic Syndrome)
      • HIV infection
      • Inhaled toxins
      • Sickle Cell Disease
      • Genetic factors – Trisomy 21 is the most common.
    • Can also be idiopathic – accounts for the majority of cases
  • Presentation and diagnosis is often delayed.
  • Initial symptoms can be non-specific.
    • Dyspnea, cough, chest pain, fatigue, syncope, palpitations
    • RED FLAGS for undiagnosed Pulmonary Hypertension: [Del Pizzo, 2016]
      • Dyspnea with exertion
      • Syncope with exertion
      • Abdominal pain with exertion
      • Look for these associated with known concerning comorbidities (ex, sickle cell disease, connective tissue disorder)
  • Can present with critical distress. [Del Pizzo, 2016]
      • Patients with pulmonary hypertension walk a tenuous tightrope where stability can be quickly jeopardized.
      • They do not tolerate hypovolemia well – but volume overload is also problematic.
      • They do not tolerate arrhythmias well, especially bradycardia!

 

Pulmonary Hypertensive Crisis: Basics

  • Occurs when pulmonary vascular resistance increases to the point that it: [Kaestner, 2016; Del Pizzo, 2016]
    • Right Ventricle (RV) pressure and volume increase.
      • Causes septum to be displaced leftward reducing Left Ventricle (LV) volume
      • Ventricular filling pressures increase as well as compensatory tachycardia and decreases in systemic vascular resistance occur.
      • Leads to drop in cardiac output and coronary blood flow andmetabolic acidosis.
    • Pulmonary blood flow decreases.
      • Leading to pulmonary arterial distension, mechanically obstructing small airways
      • Pulmonary edema develops
      • These increase Dead Space and worsen V/Q mismatch -> hypoxia and respiratory acidosis.
  • Can be triggered by: [Del Pizzo, 2016]
    • Fever
    • Hypovolemia (ex, good ol’ fashioned viral gastroenteritis)
    • Increased cardiac demand
    • Interruption of continuous prostanoid infusion
  • Presents with:
    • Tachycardia, hypotension, cool extremities, poor perfusion, and altered mental status.
    • Essentially, looks like Cold Shock, but with hyperdynamic right ventricle.
      • May hear loud single S2, holosystolic murmur.
      • May palpate engorged liver edge.

 

Pulmonary Hypertensive Crisis: Management

  • Primary goals: [Kaestner, 2016; Cunningham, 2016; Del Pizzo, 2016]
    • Reduce pulmonary vascular resistance
    • Augment RV preload and cardiac output
    • Resolve systemic hypotension and maintain coronary artery flow
    • Avoid tachyarrhythmias  
  • Primary therapies: [Kaestner, 2016; Del Pizzo, 2016]

See [Kaestner, 2016] for a nice treatment algorithm

    • Supplemental Oxygen
      • Use if Pulse Ox is < 95%
      • Adjust to typical baseline for those with congenital heart diseases.
    • Judicious fluid administration
      • Need volume to support output, but too much will exacerbate right heart failure
      • Aliquots of 5 – 10ml/kg with vigilant reassessment is advised. [Del Pizzo, 2016]
    • Inhaled Prostanoids / prostacyclin
      • Iloprost can be given IV as well.
      • Inhaled therapies have benefit in the spontaneously breathing patient
        • Can be started without IV,
        • Have less impact on systemic blood pressure.
          • May need concomitant vasopressor therapy.
          • Norepinephrine or Vasopressin [Siehr, 2016Kaestner, 2016]
          • Dobutamine, epinephrine, or milrinone may also be needed.
    • Inhaled Nitric Oxide (NO)
      • NO at 20 – 40 ppm via nasal cannula can work rapidly
      • If intubated, need to have inhaled NO continued via circuit.
    • Sildenafil
      • Can potentiate NO effects
      • Can be given orally or IV, but in critical states, IV makes more sense.
    • Normalizing blood pH
      • Acidosis causes vasoconstriction.
      • Treating acidosis with IV bicarbonate is described.
      • Goal serum pH of 7.44 has been recommended. [Kaestner, 2016]
    • Avoiding bradycardia
      • If heart rate is noted to be dropping, start chronotropic medications early.
      • Isoproterenol, a pure beta agonist, is a good choice.
  • Additional therapeutic considerations:
    • Treat the inciting event / trigger (ex, fever).
    • If a patient is on chronic IV therapies, these should be continued during treatment.
    • Sedation, anesthesia, and intubation are known risk factors for pulmonary hypertensive crisis. [Del Pizzo, 2016]
      • Avoiding intubation is best, but if required, used medications that have the least influence on hemodynamics.
      • Be prepared to give vasopressor support for pronounced fall in systemic vascular resistance!
    • ECMO may be considered. [Kaestner, 2016]

 

Moral of the Morsel

  • Chest Pain / Abdominal Pain / Syncope with exertion is Bad! Add Pulmonary Hypertension to the list of scary things that cause this.
  • Children with Pulmonary Hypertension walk upon a thin tightrope. Be ready to catch them when they fall.
  • Reduce the Pressure in the Pulmonary Vascular beds… breath in the meds!

 

References

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