Undifferentiated shock

Undifferentiated Hypotension Algorithm

Check/manage the following in order:

1. Pulse (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
2. Volume Status
   1. What is the LV end-diastolic volume?
      1. Approximated by the IVC diameter or CVP
      2. If low:
         1. Assess for blood loss versus fluid loss
            1. FAST for intra-abdominal bleed
            2. US for ruptured AAA
            3. Guaiac for GI bleed
            4. CXR for hemothorax
         2. Treat with IVF and/or pRBC depending on cause
3. Contractility
   1. Is the myocardium severely depressed in its contractile function (cardiogenic shock)?
      1. Assess via ultrasound
      2. Treat w/ inotrope
   2. Is forward flow occurring?
      1. Assess for valvular dysfunction (MR, AR)
      2. Assess for obstruction (PE, tamponade)
4. Systemic Vascular Resistance
   1. Pathologic vasodilation (decreased SVR) suggested by:
      1. Warm extremities
      2. Bounding pulse
   2. Treated based on likely etiology of distributive shock (see below)

Differential Diagnosis

1. Cardiogenic
   1. Acute valvular Regurgitation/VSD
   2. CHF
   3. Dysrhythmia
   4. ACS
   5. Myocardial Contusion
   6. Myocarditis
2. Obstructive
   1. Air embolism
   2. Aortic Stenosis
   3. Cardiac Tamponade
   4. PE
   5. Tension Pneumothorax
3. Distributive
   1. Adrenal Crisis
   2. Anaphylaxis
   3. Neurogenic Shock
   4. Sepsis
   5. Toxicologic
4. Hypovolemic
   1. Severe dehydration
   2. Hemorrhage (traumatic and non-traumatic)
      1. Classes of Hemorrhagic Shock

Class	I	II	III	IV
Blood Loss (mL)	< 750	750-1000	1500-2000	>2000
Blood Loss (%)	< 15	15-30	30-40	>40
Pulse rate (per min)	<100	100-120	120-140	>140
Blood Pressure	Normal	Normal	Decreased	Decreased
Pulse Pressure (mmHg)	Normal or Increased	Decreased	Decreased	Decreased
Respiratory Rate (per min)	14-20	20-30	30-40	>35
Urine Output (mL/hr)	>30	20-30	15-May	Negligble
Mental Status	Slightly Anxious	Mildly Anxious	Anxious, Confused	Confused, Lethargic

See Also

• Ultrasound in Shock and Hypotension
• Cardiogenic Shock

Source

• Tintinalli
• Morchi, Undifferentiated Hypotension and Shock, All LA Conference, 05/06/2010