Undifferentiated shock


  1. SBP <90 in normal pt
  2. SBP <100 with h/o HTN or age >60
  3. Lactate > 4 or base def < -4


Type Skin HR Oth
Hypovolemic cold inc
Obstructive cold inc
Cardiogenic cold inc/dec  ?dysth
Distributive warm inc
Neurogenic warm dec

Undifferentiated Hypotension Algorithm

  • Which of the following is the main cause?
  • Which of the following is contributing?

Check the following in order:

  1. HR (assess based on pt's age)
    1. Too slow or too fast? (to the point where CO is affected)
      1. If so HR is likely primary etiology of hypotension
      2. Pace or cardiovert
  1. Volume Status
    1. What is the LV end-diastolic volume?
      1. Approximated by the CVP, IVC diameter
    2. If low must rule-out occult blood loss:
      1. FAST for intra-abdominal source
      2. US to rule-out AAA
      3. Guaiac to rule-out GI bleed
      4. CXR to rule-out hemothorax

  1. Contractility
    1. Is the myocardium severely decreased in its contractile function?
      1. Poor contractility on ultrasound, bounding/thready pulse, hyperdynamic precordium
    2. Is forward flow occurring?
      1. Assess for valvular dysfunction (MR, AR)
      2. Assess for obstruction (PE, HOCM)
  1. Systemic Vascular Resistance
    1. Pathologic vasodilation (decreased SVR) suggested by:
      1. Warm extremities
      2. Bounding pulse
      3. The other three components are normal (HR, volume status, contractility)

Lack of Response to Normal Tx (DDX)

  1. Cardiogenic
    1. Acute Valvular Regurg/VSD
    2. CHF
    3. Dysrhythmia
    4. Ischemia/Infarction
    5. Myocardial Contusion/Myocarditis
  2. Obstructive
    1. Air embolism
    2. Aortic Stenosis
    3. Cardiac Tamponade
    4. Massive PE
    5. Tension Pneumo
  3. Distributive
    1. Adrenal Crisis
    2. Anaphylaxis
    3. Neurogenic
    4. Sepsis
    5. Toxicologic
  4. Hypovolemic
    1. Hemorrhage Traumatic and Non-traumatic
    2. Severe Dehydration

See Also


2/06 DONALDSON (Adapted from Tintinalli)

Morchi 2010