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Sympathetic Crashing Acute Pulmonary Edema

Sympathetic Crashing Acute Pulmonary Edema (SCAPE) also known as Acute Pulmonary Edema, Flash Pulmonary Edema, or Acute Decompensated Heart Failure is a severe life-threatening emergency that requires quick and aggressive treatment to prevent respiratory collapse. When treated appropriately by prehospital providers this condition can be lessened or reversed and prevent an afflicted patient from becoming intubated, or admitted to the ICU.


  • Demographics
    • Estimates are difficult to find.
    • Prevalence of 1-2% of western population rising with increasing age. of 2.2% for patients at 50 years, increasing to 8.4% at 75 years.
    • More likely found in women.
    • Concurrent medical history of Hypertension, Heart Attacks, and Coronary Artery Disease.
    • Typical Patient: Elderly woman with longstanding hypertension.
  • Risk Factors
    • Heart Attacks, Coronary Artery Disease, Bypass Grafts / Stents, Hypertension, Infections, Tachyarrhythmias, Drug Use, Congestive Heart Failure
  • Prescribed Medications
    • Betablockers, Diuretics, ACE Inhibitors


  • Acute injury such as a heart attack or prolonged stress of the heart muscle results in left ventricular dysfunction which causes hypotension and decreased renal perfusion.
  • Loss of arterial pressure activates the sympathetic nervous system to release catecholamines increasing heartrate and vasoconstriction, afterload increases.
  • Loss of blood flow to the kidneys activate the renin-angiotensin-aldosterone-system (RAAS) which worsens diastolic stiffening and increases diastolic pressures.
  • The effects of the catecholamines and RAAS causes intravascular fluid to permeate the pulmonary capillaries filling the interstitial and alveolar spaces.
  • TL;DR – Weak heart causes body to overcompensate and push fluid into the patient’s lungs.

Assessment Findings

  • Complaint: Severe respiratory distress with an acute onset (minutes to hours). Concurrent chest pain not uncommon, MIs are a common cause of SCAPE.
  • Mental Status: Restless, Agitated, Panicked. Tired, Weakness and Confusion is a sign of impending respiratory collapse.
  • Airway: Usually clear. Pink frothy sputum is possible and is a distinguishing factor for pulmonary edema.
  • Breathing: Rapid and labored. Bilateral rales is another distinguishing factor of pulmonary edema. Pulse Oximetry will be low.
  • Circulation: Tachycardic. Hypertensive (often 180 mmHg or greater). Skin may be diaphoretic and jugular vein distention may be found during assessment.
  • Diagnostic Testing
    • 12-Lead EKG: Check of Cardiac Injury or Ischemia and tachyarrhythmias.
    • Pulse Oximetry: 70s, 80s or lower.


Fast aggressive treatment is needed to prevent patient collapse.


  • Non-Invasive Ventilation
    • Will provide oxygentation as well as stent open the affected alveoli for improved gas exchange.
    • BiPAP may show some advantages to CPAP but both are safe and effective.
    • Holding the mask on the patient’s face will make it more tolerable and allow rapid removal if intubation is necessary.
    • Start at 6 mmH2O of pressure and increase to 12-14 mmH2O until improvement.
  • High Dose Nitroglyercine
    • Targeted reduction of afterload to help restore correct pulmonary pressures and return fluid to the intravascular space.
    • High Dose Nitro is safe for patients suffering from SCAPE. Intravenous bolus doses of up to 2 mg have been used safely and effectively. In the unlikely event hypotension occurs it can be resolved with a normal saline bolus.
    • Dosage:
      • Sublingual Nitro Tab or Spray (0.4 mg)
        • Systolic Blood Pressure > 200 mmHg give Nitro SL x3 (1.2 mg) q 5 min
          Systolic Blood Pressure > 160 mmHg give Nitro SL x2 (0.8 mg) q 5 min
          Systolic Blood Pressure > 120 mmHg give Nitro SL x1 (0.4 mg) q 5 min
      • Titrate to relief and a target Systolic Blood Pressure of 140 mmHg
    • Intubation
      • May be required if respiratory failure occurs. First pass success is and preoxygenation will be difficult.
Cite this article as: Scott Kostolni, EMT-P, "Sympathetic Crashing Acute Pulmonary Edema," from SickPatient.com, February 3, 2018, date accessed: November 28, 2022 https://sickpatient.com/scape/

References and Resources

  1. Agrawal, Naman, et al. “Sympathetic crashing acute pulmonary edema.” Indian Journal of Critical Care Medicine , vol. 20, no. 12, 2016, p. 719. Health Reference Center Academic ,
  2. Anand Swaminathan, M. (2015). Acute Pulmonary Edema. [online] Core EM. Available at: https://coreem.net/core/ape/ [Accessed 4 Feb. 2018].
  3. Scott Weingart. EMCrit Podcast 1 – Sympathetic Crashing Acute Pulmonary Edema (SCAPE). EMCrit Blog. Published on April 25, 2009. Accessed on June 29th 2017. Available at [https://emcrit.org/emcrit/scape/ ]
  4. Clemency, B., Thompson, J., Tundo, G., & Lindstrom, H. (2013). Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension. Prehospital and Disaster Medicine, 28(5), 477-481. doi:10.1017/S1049023X13008777
  5. Walenczak, D. (2017). Episode 18: Dry Land Drowning. [online] CritMedic. Available at: https://www.critmedic.com/podcasts/episode-18-dry-land-drowning/ [Accessed 4 Feb. 2018].