The shock index calculator works out mean arterial pressure (map), modified shock index (msi) and age shock index (age si) from age, diastolic blood pressure (dbp), heart rate (hr), systolic blood pressure (sbp) and one way. Enter what you have and the relationship is applied straight away, so you get the answer without working through the algebra yourself.
What Is the Shock Index Calculator?
The shock index calculator gives you an estimate of mean arterial pressure (map), modified shock index (msi) and age shock index (age si) based on age, diastolic blood pressure (dbp), heart rate (hr), systolic blood pressure (sbp) and one way.
It is a quick reference figure rather than a diagnosis, and it is most useful for tracking how a number moves over time rather than for interpreting a single reading.
How the Shock Index Estimate Is Worked Out
The calculation follows published reference relationships, so it is a reasonable approximation when the inputs are accurate. It assumes an average adult and does not account for individual variation.
If you are comparing two people, or the same person over a period of weeks, keep the method and the inputs identical. A change in the method can easily look like a change in the person.
What This Calculator Does Not Do
It does not diagnose anything, and it does not replace advice from a clinician. If a figure comes out at an extreme, or if it differs sharply from what you expect, that is a reason to speak to a professional rather than to adjust the inputs.
Nothing you type here is stored or sent anywhere. The whole calculation happens in your browser.
A Worked Example
Working through an example, with age set to 10, diastolic blood pressure (dbp) set to 5, heart rate (hr) set to 2, the calculator returns shock index (si) of 0.02, and mean arterial pressure (map) of 36.67, and age shock index (age si) of 0.2. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out mean arterial pressure (map)?
Enter age, diastolic blood pressure (dbp), heart rate (hr), systolic blood pressure (sbp) and one way. The calculator then works through the relationship and reports mean arterial pressure (map), modified shock index (msi) and age shock index (age si).
What does the shock index actually calculate?
It takes age, diastolic blood pressure (dbp), heart rate (hr), systolic blood pressure (sbp) and one way and converts them into mean arterial pressure (map), modified shock index (msi) and age shock index (age si) using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter age?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.