EM@3AM: Pulmonary Hypertension

Author: Katharine White, MD (EM Resident Physician, UTSW/Parkland Memorial Hospital) // Edited by: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX) and Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 65F presents to your emergency department complaining of chest pain and shortness of breath. She states her symptoms have been going on for several months and have been progressively worsening. She states that she has felt this way since she was diagnosed with a “blood clot in her lungs” several months ago. VS include T 37.5C, BP 101/71, HR 103, RR 22, Pox 89% on RA.

What should you consider, and what’s your next step in evaluation and treatment?

Answer: Pulmonary Hypertension (PH)

1. When to think PH:¹

• Dyspnea (with rest or with exertion)
• Fatigue
• Chest Pain
• Syncope
• Exertional lightheadedness
• Physical exam is often normal and early diagnosis is often missed: average interval between symptom onset and diagnosis is 2 years
• Patients with severe pulmonary HTN can develop signs of R heart failure (JVD, hepatomegaly, ascites, edema)

2. Brief Overview of Pathophysiology:

• Pulmonary vasculature is meant to be a high-flow, low-resistance circuit
• Normal PA systolic pressures range from 10-30
• PH defined as PA pressure >25 at rest or >30 during exertion. Definitive diagnosis via right heart catheterization¹
• Why the RV fails:
  • Increased RV afterload
  • Reduced RV perfusion and contractility
  • Changes in RV preload

3. Five flavors of pulmonary HTN: ¹

• Group 1: Pulmonary arterial HTN
  • Idiopathic
  • Genetic/Heritable abnormalities
  • Drug/Toxin induced
  • Associated with known risk factors (HIV, liver disease, collagen vascular disorders)
• Group 2: Pulmonary venous HTN (left heart disease)
  • Systolic or diastolic dysfunction
  • Mitral or aortic valve disease
• Group 3: Chronic hypoxemic lung disease
  • Obstructive lung disorders (COPD)
  • Interstitial Lung Disease
  • Idiopathic Pulmonary Fibrosis
  • Sleep-Disordered breathing (OSA)
• Group 4: Embolic disease (PE)
• Group 5: Miscellaneous

4. The Workup

• EKG:
  • Most common abnormality is right axis deviation
  • Signs of R heart strain: S1Q3T3, right atrial enlargement in the inferior leads, incomplete/complete RBBB
• Labs:
  • CBC, CMP often nonspecific
  • BNP often elevated and correlates with outcomes
  • Elevations in troponin are associated with higher morbidity and mortality
• CXR
  • Can demonstrate signs of RV failure – enlarged RA, RV, pulmonary arteries
  • Can demonstrate underlying etiology – hyperinflation, ILD, edema
• Echo
  • Best initial diagnostic test
  • Apical four chamber helpful to evaluate size of RV relative to LV and assess for septal deviation
  • US not helpful in assessing volume status in these patients!

5. Management

• For every patient:
  • Think back to the basics: IV, O2, Monitor – ensure adequate access is obtained!
  • Give life-sustaining home medications:
    • Is the patient on a pulmonary vasodilator via pump? Is the pump functioning correctly? Is the cassette out of medication? Is the catheter clogged?
    • Restart medications quickly
  • Consult your specialists as early on in the course as possible.
• Further management considerations can often be thought of in considering the 3 Ps: Preload, Pump and Pipes
  • RV function determined by 3Ps: Preload, Pump, Pipes
  • Preload:
    • Assessing volume can be difficult in this patient population.
    • Consider gentle hydration (250cc IVF) vs. gentle diuresis based on your history and physical exam
  • Pump:^{1, 3}
    • Cardiovert dysrhythmias as indicated
    • Consider inotropic support

• • • • Dobutamine 2-10 mcg/kg/min
      • Milrinone 0.375mcg/kg/min (can cause hypotension)
    • Are you getting adequate perfusion to the heart?
      • Consider low dose norepinephrine (0.05–0.75mcg/kg/min) to maintain coronary artery perfusion
  • Pipes: (afterload)
    • Consider Pulmonary vasodilators
    • Prostanoids, endothelin receptor antagonists, and phosphodiesterase-5 (PDE-5) inhibitors
    • Prostanoids are treatment of choice
      • Epoprostenol is the only therapy proven to improve survival
      • Can be given by peripheral IV
  • Don’t forget to address underlying etiology of their exacerbation. Treat the pneumonia, sepsis, vomiting, etc. that you found on your thorough workup.
• BEWARE OF INTUBATION:
  • Intubation can cause rapid cardiovascular collapse due to increased Pulmonary Vascular Resistance and decreased preload³
  • If you must intubate, have vasopressors at bedside
  • Low TV, low PEEP ventilation strategy
  • Avoid hypercapnia, which can increase pulmonary vascular resistance, pulmonary artery pressure, and RV strain

References:

1. Tintinalli J, Stapczynski J, Ma OJ et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, Seventh Edition (Book and DVD). Mcgraw-hill; 2010.
2. Wilcox SR, Kabrhel C, Channick RN. Pulmonary Hypertension and Right Ventricular Failure in Emergency Medicine. Ann Emerg Med. 2015;66(6):619-28.
3. Zamanian RT, Haddad F, Doyle RL, Weinacker AB. Management strategies for patients with pulmonary hypertension in the intensive care unit. Crit Care Med. 2007;35(9):2037-50.