Shock Index Calculator


Shock Index Calculator

Hello there, fellow number crunchers! Brace yourselves as we dive into the thrilling world of the Shock Index. You’ll be as surprised as a cat watching a horror movie!


The Shock Index (SI) is a simple calculation where the heart rate takes a nosedive off the diving board and is divided by the systolic blood pressure. Here’s the formula, landing with a splash:

Shock Index = Heart Rate / Systolic Blood Pressure

Now, let’s get serious.

Shock Index Categories

Category Shock Index Range (Imperial Units) Interpretation
Normal ≤ 0.7 No shock
Mild 0.7 – 0.9 Possible shock
Moderate 0.9 – 1.3 Likely shock
Severe > 1.3 Severe shock

Shock Index Calculation Examples

Individual Heart Rate Systolic Blood Pressure Shock Index Calculation
Mr. Fast Heart 120 bpm 100 mmHg 1.2 120 / 100 = 1.2
Mrs. Low Pressure 80 bpm 60 mmHg 1.3 80 / 60 = 1.3
Ms. Normal 70 bpm 120 mmHg 0.58 70 / 120 = 0.58

Shock Index Calculation Methods

Method Advantages Disadvantages Accuracy
Standard SI Simple, widely used Doesn’t consider age or sex Moderate
Age-adjusted SI Considers age More complex High

Evolution of Shock Index

Year Change
1960s SI introduced
1990s SI applied to trauma patients
2000s SI incorporated into early warning scores

Limitations of Shock Index

  1. Doesn’t consider age or sex: The standard SI doesn’t take into account age or sex, which can influence vital signs.
  2. Less accurate for certain conditions: The SI may be less accurate for conditions like sepsis or heart failure.

Alternative Methods

Method Pros Cons
Mean arterial pressure Considers both systolic and diastolic BP More complex
Pulse pressure Simple to calculate Less accurate


  1. What is the Shock Index? The Shock Index is a medical calculation used to assess the severity of a patient’s condition.
  2. How is the Shock Index calculated? The Shock Index is calculated by dividing a patient’s heart rate by their systolic blood pressure.
  3. Why is the Shock Index important? It can help detect shock early and predict severity of conditions like sepsis or heart failure.
  4. What is a normal Shock Index? A normal Shock Index is less than or equal to 0.7.
  5. What is considered a high Shock Index? A Shock Index higher than 1.3 is considered severe shock.
  6. Can Shock Index predict mortality? Yes, a higher Shock Index can indicate a higher risk of mortality.
  7. What are the limitations of the Shock Index? SI doesn’t consider age or sex and may be less accurate for conditions like sepsis.
  8. What are alternatives to the Shock Index? Alternatives include Mean arterial pressure and Pulse pressure.
  9. Where can I find more information about the Shock Index? You can find more information at the CDC and NIH websites.
  10. How can I calculate the Shock Index? You can calculate it manually using the formula or use a Shock Index calculator.


  1. CDC: The CDC provides a wealth of information on vital signs and their importance in assessing patient health.
  2. NIH: The NIH offers numerous research papers and resources on the Shock Index and its uses in medicine.