Cardiogenic shock

Background

  • Leading cause of death in patients with ACS who reach the hospital alive

Etiologies

Clinical Features

Physical Exam

Differential Diagnosis

Shock

Evaluation

Workup

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%)
    • Combination of BNP with clinician judgment 94% sensitive 70% specific (compared to 49% sn and 96% spec clinical judgement alone) [2]

NT-proBNP[3][4][5]

  • <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

General

Aim for MAP >65

  1. Consider etiologies (see above) and treat specific one, if present
  2. Consider small fluid challenge (250-500cc normal saline IV) or fluid removal, depending on estimation of patient's point on Starling curve
  3. Increase inotropy
  4. Consider transfusion if hemoglobin < 10 (be aware of added fluid)
  5. Consider intubation
    • Decreases O2 demand BUT may worsen preload

Mitral Regurgitation

Increase forward flow

ACS

  • PCI or thrombolysis

Aortic stenosis

Decrease afterload (with extreme caution in very small, carefully-titrated doses)

  • Agents:
  • Do not give preload reducers such as nitro
  • Patients are flow dependent over stenotic value. Flow proportional to degree of stenosis and afterload.

Toxins

Vasopressors

PressorInitial DoseMax DoseCardiac EffectBP EffectArrhythmiasSpecial Notes
Dobutamine3-5 mcg/kg/min5-15 mcg/kg/min (as high as 200) [6]Strong ß1 agonist +inotrope +chronotrope, Weak ß2 agonist +weak vasodilatation )alpha effect minimalHR variable effects [7]. Also Increase SA and AV node fxindicated in decompensated systolic HF, Debut Research 1979[8] Isoproterenol has most Β2 vasodilatory and Β1 HR effects
Dopamine2 mcg/kg/min20-50 mcg/kg/minβ1 and NorEpi releaseα effects if > 20mcg/kg/minArrhythmogenic from β1 effectsMore adverse events when used in shock compared to Norepi[9]
Epinepherine0.1-1 mcg/kg/min+ inotropy, + chronotropy
Norepinephrine0.2 mcg/kg/min0.2-1.3 mcg/kg/min (5mcg/kg/min) [10]mild β1 direct effectβ1 and strong α1,2 effectsLess arrhythmias than Dopamine[9]First line for sepsis. Increases MAP with vasoconstriction, increases coronary perfusion pressure, little β2 effects.
Milrinone50 mcg/kg x 10 min0.375-75 mcg/kg/minDirect influx of Ca2+ channelsSmooth muscle vasodilatorPDE Inhibitor which increases Ca2+ uptake by sarcolemma. No venodilatory activity
Phenylephrine100-180 mcg/min then 40-60 mcg/min0.4-9 mcg/kg/minAlpha agonistLong half life
VasopressinFixed Dose0.01 to 0.04 U/minunknownincreases via ADH peptideshould not be titrated due to ischemic effects
Methylene blue[11]IV bolus 2 mg/kg over 15 min1-2 mg/kg/hourPossible increased inotropy, cardiac use of ATPInhibits NO mediated peripheral vasodilationDon't use in G6PD deficiency, ARDS, pulmonary hypertension
Medication IV Dose (mcg/kg/min) Concentration
Norepinephrine (Levophed)0.1-2 mcg/kg/min8mg in 500mL D5W
Dopamine2-20 mcg/kg/min400mg in 250 D5W
Dobutamine2-20 mcg/kg/min250mg in 250 mg D5W
Epinephrine0.1-1 mcg/kg/min1mg in 250 D5W

Disposition

  • Admission, frequently to intensive or higher-level of care

See Also

Video

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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. McCullough et al. B-Type natriuretic peptide and clinical judgment in emergency diagnosis of heart failure: analysis from breathing not properly (BNP) multinational study. Circulation. 2002:DOI: 10.1161/01.CIR.0000025242.79963.4
  3. 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.
  4. 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.
  5. 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.
  6. https://www.ncbi.nlm.nih.gov/pubmed/8449087
  7. Edmund H. Sonnenblick, M.D., William H. Frishman, M.D., and Thierry H. LeJemtel, M.D. Dobutamine: A New Synthetic Cardioactive Sympathetic Amine
  8. De Backer Daniel et al. Comparison of Dopamine and Norepinephrine in the Treatment of Shock. NEJM 363(9). 779-789
  9. https://www.ncbi.nlm.nih.gov/pubmed/15542956
  10. Pasin L et al. Methylene blue as a vasopressor: a meta-analysis of randomised trials. Crit Care Resusc. 2013 Mar;15(1):42-8.
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