Recommended Citation: Dorritie M. Critical Care Pearls - Sympathetic Crashing Acute Pulmonary Edema [Internet]. Cook County Emergency Medicine Residency;Available from: https://cookcountyem.com/blog/2023/11/19/critical-care-pearls-sympathetic-crashing-acute-pulmonary-edema
The Case:
A 55-year-old female with a past medical history of hypertension, end-stage renal disease (ESRD) on hemodialysis, insomnia, depression, and opioid use disorder presents with rapidly worsening dyspnea that began several hours prior to arrival. She endorses an associated cough productive of clear sputum and admits to inhalation opioid use the day prior. She most recently received hemodialysis two days earlier and has not missed any sessions recently.
Initial vitals were remarkable for BP 263/149 mmgHg, HR 125 bpm, RR 34 bpm, SpO2 80% on 6L O2 via nasal cannula, and temperature 36.3oC. Her exam was remarkable for a dry oral mucosa, significant dyspnea and tachypnea with accessory muscle use, and diffuse crackles bilaterally. Cardiopulmonary point-of-care ultrasound (POCUS) evaluation was notable for bilateral B lines (Figure 1) and grossly reduced EF with IVC reflux and significant LV hypertrophy and LA dilation (Figure 2).
Figure 2: Still image of subxiphoid cardiac POCUS view demonstrating IVC dilation with reflux.
The patient’s clinical presentation raised concerns for sympathetic crashing acute pulmonary edema (SCAPE), otherwise known as flash pulmonary edema. Despite the initiation of nitroglycerin drip and BiPAP, the patient decompensated and was ultimately intubated and admitted to the medical ICU. Her treatment further included a nicardipine drip and volume management, after which she was extubated two days later and discharged home several days thereafter.
Discussion:
SCAPE is a must-catch diagnosis for any emergency physician. The disease process is most often characterized by rapid-onset dyspnea, hypoxia, significant hypertension (SBP >180 mmHg), crackles on exam, and B-lines on POCUS (1). Patients with poorly controlled volume statuses – such as patients with ESRD or heart failure with reduced ejection fracture (HFrEF) – are most frequently susceptible to developing SCAPE.
Notably, SCAPE has a different pathophysiologic mechanism from decompensated heart failure exacerbations or hypotensive cardiogenic shock, which may present similarly (2). SCAPE occurs primarily due to sympathetic overdrive, whereby systemic vasoconstriction leads to markedly increased afterload (1). This causes fluid to back up into the patient’s lungs and further exacerbates the patient’s sensation of dyspnea, leading to a dangerous cycle for the patient. For this reason, symptoms develop rapidly over the course of only a few hours. Moreover, patients with SCAPE often present euvolemic or hypovolemic.
The goal of treatment is to rapidly reduce afterload to empty fluid out of the lungs. Blood pressure reversal need not be titrated slowly as with many other hypertensive emergencies. Thus, the hallmarks of treatment include high-dose nitroglycerin (preferably a drip, though you may start with sublingual or patch treatments if more readily available) and BiPAP/CPAP (3,4). Titrate BiPAP/CPAP up quickly with a high expiratory pressure. If the patient is still not improving, physicians may consider further hypertensive control with a clevidipine or nicardipine drip and intubation for respiratory support. Diuretics such as furosemide may play a role in the hypervolemic patient, though they are typically unnecessary in providing clinical improvement (5).
Take Home Points:
SCAPE is a true medical emergency requiring rapid diagnosis and treatment. Your history and physical exam may be aided by cardiopulmonary POCUS findings to intervene early in the patient’s course.
The hallmarks of treatment are high-dose nitroglycerin and BiPAP/CPAP. Adjunctive therapies to consider include a clevidipine or nicardipine drip, as well as intubation.
Unlike decompensated heart failure exacerbations or hypotensive cardiogenic shock, SCAPE is a consequence of sympathetic overdrive, not systemic hypervolemia. Therefore, diuretics play a limited role in management.
Authored by Michael Dorritie, DO
References:
Farkas J. Sympathetic Crashing Acute Pulmonary Edema (SCAPE). The Internet Book of Critical Care. August 31, 2021. https://emcrit.org/ibcc/scape/
Clark SB, Soos MP. Noncardiogenic Pulmonary Edema. In: StatPearls. Treasure Island (FL): StatPearls Publishing; October 1, 2020.
Haber et al. Bolus intravenous nitroglycerin predominantly reduces afterload in patients with excessive arterial elastance. J Am Coll Cardiol. 1993;22(1):251-257.
Paone S, Clarkson L, Sin B, Punnapuzha S. Recognition of Sympathetic Crashing Acute Pulmonary Edema (SCAPE) and use of high-dose nitroglycerin infusion. Am J Emerg Med. 2018 Aug;36(8):1526.e5-1526.e7. doi:10.1016/j.ajem.2018.05/013
Agrawal N, Kumar A, Aggarwal P, Jamshed N. Sympathetic crashing acute pulmonary edema. Indian J Crit Care Med. 2016 Dec;20(12):719-723. doi:104103/0972-5229.195710