II. Indications

III. Background

  1. Shock Index provides early identification of compensated shock at risk for decompensation
    1. Shock Index may indicate more ill patients with less reserve when Blood Pressure is "soft" without frank Hypotension
  2. Diastolic Shock Index similarly may identify compensated shock patients
    1. Catecholamine surge may transiently raise Blood Pressure by increasing Heart Rate, Cardiac Output and vascular tone
      1. Catecholamine surge may be signaled by episodic Hypotension that corrects
      2. However, ultimately Hypotension is expected when Catecholamine effects are exhausted

IV. Exam: Shock Index (Systolic Shock Index)

  1. Shock Index = (Heart Rate) / (Systolic Blood Pressure)
    1. Systolic Blood Pressure reflects Cardiac Output
  2. Interpretation
    1. Normal: 0.5 to 0.7
    2. Mild Shock: 0.7 to 1.0
    3. Moderate Shock: 1.0 to 1.4
    4. Severe Shock: >1.4
  3. Efficacy
    1. Shock Index (by contrast with Vital Signs) does correlate with degree of Hemorrhage
    2. Mutschler (2013) Crit Care 17(4): R172 [PubMed]

V. Exam: Diastolic Shock Index (DSI)

  1. Diastolic Shock Index = (Heart Rate) / (Diastolic Blood Pressure)
    1. Diastolic Blood Pressure reflects vascular tone (Peripheral Vascular Resistance)
  2. Interpretation
    1. Compensated Shock at risk of decompensation: >2.5

VI. References

  1. Weingart and Swaminathan in Swadron (2022) EM:Rap 22(11): 2-3

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