Sympathetic crashing acute pulmonary edema (SCAPE)

Background

  • Different from acute CHF exacerbation or hypotensive cardiogenic shock, which do not have sympathetic overdrive
  • Patients can decompensate rapidly, so rapid intervention required
  • Patients are generally more fluid depleted despite "wet" lungs, so do not give diuretics
  • Usually history of poorly controlled hypertension
    • Acute afterload increase causes pulmonary edema and poor peripheral perfusion
    • Sympathetic surge occurs as a result of decreased systemic perfusion
    • Afterload further increases and patient rapidly decompensates
Pulmonary edema with small pleural effusions on both sides.

Clinical Features

  • Rales, crackles
  • SBP >180 mmHg
  • Tachycardic

Differential Diagnosis

Pulmonary Edema Types

Cardiogenic pulmonary edema

Noncardiogenic pulmonary edema

Evaluation

  • CBC (rule out anemia)
  • Chem
  • ECG
  • CXR - signs of pulmonary congestion may not show for hours after acute flash pulmonary edema, so normal CXR is frequently seen
    • Cephalization
    • Interstitial edema
    • Pulmonary venous congestion
    • Pleural effusion
    • Alveolar edema
    • Cardiomegaly
  • Troponin
  • Ultrasound
  • Consider arterial line monitoring for titration of NTG

Brain natriuretic peptide (BNP)[1]

  • Measurement
    • <100 pg/mL: Negative for acute CHF (Sn 90%, NPV 89%)
    • 100-500 pg/mL: Indeterminate (Consider differential diagnosis and pre-test probability)
    • >500 pg/mL: Positive for acute CHF (Sp 87%, PPV 90%)

NT-proBNP[2][3][4]

  • <300 pg/mL → CHF unlikely
  • CHF likely in:
    • >450 pg/mL in age < 50 years old
    • >900 pg/mL in 50-75 years old
    • >1800 pg/mL in > 75 years old

Management

Vasodilate arterial side, while maintaining oxygenation

  • BiPAP with PEEP of 8 mmHg
    • Titrate PEEP quickly to 12
  • High dose nitroglycerin over 2 min (at these doses, nitroglycerin has vasodilation > venodilation[5])
    • Goal BP at the patient's norm
    • Load 800 mcg over 2 min (may start at 100 mcg/min, then titrate rapidly to 400 mcg/min for 2 min)
    • Then start maintenance at 100 mcg/min, titrate up as needed
    • NOTE: it takes time to set up nitroglycerin drip, so consider SL nitroglycerin in interim
      • 0.4mg tab during 5 min = ~80 mcg/min (2 tabs = ~160 mcg/min, etc.)
      • Difficult to titrate if giving more than 1-2 tabs
  • Patients are likely more dehydrated that overloaded but should be recurrently volume assessed
  • Consider captopril 12.5 - 25mg SL for continuation of afterload reduction[6]
  • Wean CPAP after sustained BP at patient's baseline
    • Decrease FiO2 to 40%
    • Wean PEEP down 2 cm H2O q10 min
    • At 5 cmH2O, trial of NC

Other Interventions

  • Furosemide
    • Targets kidneys which are poorly perfused in BOTH hypotension and catecholamine surge
    • Consider waiting until BiPAP and nitroglycerin control hypertension first
  • Nitroprusside, alternative when insufficient response to NTG
    • Start 0.5 mcg/kg/min, titrate to blood pressure
    • Max 10 mcg/kg/min for x10 min
    • Cyanide toxicity risk increases proportionately with infusion rate as well as length of time[7]
  • If intubation required, consider delayed sequence intubation

Disposition

  • Admit

See Also

External Links

References

  1. Maisel AS, Krishnaswamy P, Nowak RM, et al. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med. 2002;347(3):161-167. doi:10.1056/NEJMoa020233.
  2. Januzzi JL, van Kimmenade R, Lainchbury J, et al. NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1256 patients: the International Collaborative of NT-proBNP Study. Eur Heart J. 2006 Feb. 27(3):330-7.
  3. Kragelund C, Gronning B, Kober L, Hildebrandt P, Steffensen R. N-terminal pro-B-type natriuretic peptide and long-term mortality in stable coronary heart disease. N Engl J Med. 2005 Feb 17. 352(7):666-75.
  4. Moe GW, Howlett J, Januzzi JL, Zowall H,. N-terminal pro-B-type natriuretic peptide testing improves the management of patients with suspected acute heart failure: primary results of the Canadian prospective randomized multicenter IMPROVE-CHF study. Circulation. 2007 Jun 19. 115(24):3103-10.
  5. Haber et al. Bolus intravenous nitroglycerin predominantly reduces afterload in patients with excessive arterial elastance. J Am Coll Cardiol. 1993;22(1):251-257.
  6. Hamilton RJ, Carter WA, Gallagher JE. Rapid Improvement of acute pulmonary edema with sublingual captopril. Acad Emerg Med 1996; 3: 205-12.
  7. GlobalRPH. Nitroprusside (Nipride®). http://www.globalrph.com/nitroprusside_dilution.htm