Cardiogenic shock

Revision as of 02:22, 8 January 2014 by Mceledon83 (talk | contribs)

Background

  • Leading cause of death in pts w/ MI who reach the hospital alive

Physical Exam

  • Assess for signs of CHF
    • elevated JVD, pulmonary edema, S3
  • Assess for valvular disease (MR, critical AS, or aortic regurgitation)
  • Assess e/o end-organ hypoperfusion
    • cool/mottled extremities, weak pulses, AMS, decreased UOP
  • Assess for pulsus paradoxus (cardiac tamponade)

Work-Up

  • Labs
    • Troponin
    • Lactate
    • CBC
    • Chem
    • BNP
      • <100 may rule-out cardiogenic shock
  • ECG
  • CXR
  • TTE

Etiology

  • Myocardial infarction
    • Pump failure
    • Mechanical complications
    • Acute MR (papillary muscle rupture)
    • VSD
    • Free-wall rupture
  • RV infarction
  • Decreased forward flow
    • Sepsis
    • Rate-related
      • Bradycardia
      • Tachycardia
    • Myocarditis
    • Myocardial contusion
    • Cardiomyopathy
  • Mechanical obstruction to forward flow
    • AS
    • HOCM
    • Mitral stenosis
    • Pericardial
  • LV regurgitation
    • Chordal rupture
    • Aortic insufficiency

DDX

  • MI
  • PE
  • COPD exacerbation
  • Peri/myocarditis
  • Aortic dissection
  • Pericardial tamponade
  • Acute valvular insufficiency
  • Sepsis
  • Hemorrhage
  • Toxins/drugs of abuse

Treatment

  • General
    • Intubation
      • Decreases O2 demand BUT may worsen preload
  • Coronary perfusion
  1. Small Fluid challenge
  2. Increase inotropy
    1. Titrate to clinical effect
      • Dobutamine or Milrinone:
      1. Use milrinone if pt is on BB
      2. CaCl 1gm
        1. Give if pt is hypocalcemic
  3. Achieve MAP >65

Pressors

Pressor Initial Dose Max Dose Cardiac Effect BP Effect Arrhythmias Special Notes
Dobutamine 2.5mcg/kg/min 10-40 mcg/kg/min mainly inotrope (ß1) alpha effect minimal Some HR(ß1) increase. Also Increase SA and AV node fx Debut Research 1979[1] Isoproterenol has most Β2 vasodilatory and Β1 HR effects
Dopamine 2mcg/kg/min 20-50 mcg/kg/min β1 and NorEpi release α effects if > 20mcg/kg/min Arrhythmogenic from β1 effects More adverse events when used in shock compared to Norepi[2]
Norepinephrine 8-12mcg/min 30 mcg/min β1 direct effect β1 and α1,2 effects Less arrhythmias than Dopamine[2] Increases MAP, coronary perfusion pressure, little β2 effects.
Milrinone 50mcg/kg x 10 min 0.375-75mcg/kg/min Direct influx of Ca2+ channels Smooth muscle vasodilator PDE Inhibitor which increases Ca2+ uptake by sarcolemma. No venodilatory activity
Phenylephrine 100-180mcg/min then 40-60mcg/min 0.4-9 mcg/kg/min Alpha agonist Long half life
Vasopressin Fixed Dose 0.4 U/min unknown increases via ADH peptide should not be titrated due to ischemic effects

Other Therapies

  • Transfusion
    • Consider if Hb < 10

Specific Situations

  1. Mitral Regurg
    1. Need to increase forward flow
    2. Dobutamine (contractility)
    3. Nitroprusside (afterload reduction)
  2. MI
    1. PCI or thrombolysis
  3. Aortic Stenosis
    1. Do not give preload reducers such as Nitro
    2. Patients are flow dependent over stenotic value. Flow proportional to degree of stenosis and afterload.
    3. Maintain flow by decreasing afterload (use with extreme caution and in very small carefuly titrated doses)
      1. Nitropruside
      2. Dobutamine
      3. Hydralazine
  4. Toxins
    1. Beta-Blocker Toxicity
    2. Calcium Channel Blocker
    3. Digoxin

See Also

Source

Tintinalli EMCrit Podcast 10

  1. Edmund H. Sonnenblick, M.D., William H. Frishman, M.D., and Thierry H. LeJemtel, M.D. Dobutamine: A New Synthetic Cardioactive Sympathetic Amine
  2. 2.0 2.1 De Backer Daniel et al. Comparison of Dopamine and Norepinephrine in the Treatment of Shock. NEJM 363(9). 779-789