PESI score: how the Pulmonary Embolism Severity Index adds up

The Pulmonary Embolism Severity Index (PESI) is a point score for a person with a pulmonary embolism that has already been confirmed. It starts with the person's age in years and adds points for male sex, cancer, heart failure, chronic lung disease, five vital-sign findings and altered mental status. A 50-year-old woman with none of the other items scores 50.

Not a medical device. Not a diagnosis or dosing recommendation.

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Aujesky D et al. · 2005
The PESI formula
Worked examples
Frequently asked questions

What is the PESI score?

PESI was published by Aujesky and colleagues in the American Journal of Respiratory and Critical Care Medicine in 2005. It's also called the PE severity index or the Aujesky PESI. Magent's calculator is the original PESI, with heart failure and chronic lung disease as two separate items. It isn't the simplified PESI (sPESI).

This page explains the arithmetic. The class limits appear only in the exact expression the calculator uses, below; this page doesn't turn a score into an outcome or say what a score means for a particular person.

The PESI formula

PESI = age in years
     + 10 male + 30 cancer + 10 heart failure + 10 chronic lung disease
     + 20 heart rate ≥ 110 + 30 systolic BP < 100 + 20 respiratory rate ≥ 30
     + 20 temperature < 36 °C + 60 altered mental status + 20 SpO2 < 90%

Exact expression the calculator uses:

PESI = age_in_years + 10*male + 30*cancer + 10*heart_failure + 10*chronic_lung_disease + 20*(HR>=110) + 30*(SBP<100) + 20*(RR>=30) + 20*(temp<36) + 60*altered_mentation + 20*(SpO2<90); classes I <=65, II 66-85, III 86-105, IV 106-125, V >125

What each part means

Item	What earns points	Points
Age	Age in years (18 to 120)	Same as the age
Sex	Male	10
Cancer	Present	30
Heart failure	Present	10
Chronic lung disease	Present	10
Heart rate	110 beats per minute or more	20
Systolic blood pressure	Below 100 mm Hg	30
Respiratory rate	30 breaths per minute or more	20
Temperature	Below 36 °C	20
Altered mental status	Present	60
Oxygen saturation (SpO2)	Below 90%	20

How the score works

Start with age. Age 50 contributes 50 points; age 80 contributes 80.
Add the history items. Male sex adds 10, cancer 30, heart failure 10 and chronic lung disease 10. Heart failure and chronic lung disease count separately.
Add the vital signs. Heart rate of 110 or more adds 20, systolic pressure under 100 adds 30, respiratory rate of 30 or more adds 20, temperature under 36 °C adds 20, and SpO2 under 90% adds 20.
Add mental status. Altered mental status adds 60.
The sum is the score. There's no fixed maximum, because age is added as a number.

Inputs come from the user

The record says the person using the calculator supplies every input. Cancer, heart failure, chronic lung disease and altered mental status are true/false answers. Magent's calculator doesn't examine anyone. It takes age from 18 to 120, heart rate from 30 to 220, systolic pressure from 50 to 250 mm Hg, respiratory rate from 4 to 80, temperature from 30 to 45 °C and SpO2 from 50 to 100%. It returns the total, the age it used and a line for each item.

Worked examples

These are the worked examples in Magent's record for the calculator.

Example 1: age 50, female, nothing else

Age 50 → 50. Female → 0. No cancer, heart failure or chronic lung disease → 0.
Heart rate 80, systolic pressure 120, respiratory rate 16, temperature 37.0 °C and SpO2 96% don't meet any threshold → 0.
No altered mental status → 0.
Score = 50.

Example 2: age 80, male, cancer, altered mental status

Age 80 → 80. Male → 10. Cancer → 30. Altered mental status → 60.
Nothing else is present.
Score = 180.

Values at the boundaries

Each line changes one item from Example 1. All are Magent's expected values for the calculator.

Heart rate 109 → 50; heart rate 110 → 70.
Systolic pressure 100 → 50; systolic pressure 99 → 80.
Respiratory rate 29 → 50; respiratory rate 30 → 70.
Temperature 36.0 °C → 50; temperature 35.9 °C → 70.
SpO2 90% → 50; SpO2 89.9% → 70.
Altered mental status → 110.

History of PESI

The score comes from Aujesky D, Obrosky DS, Stone RA and colleagues, Derivation and validation of a prognostic model for pulmonary embolism, American Journal of Respiratory and Critical Care Medicine, 2005 (volume 172, issue 8, pages 1041–1046).

When it's used

Magent's record limits the calculator to people whose pulmonary embolism has already been confirmed, as in the 2005 paper. It isn't a test for whether someone has a pulmonary embolism.

Where it's used

The inputs are things recorded at the bedside: age, sex, a short history, vital signs and mental status.

Who uses it

The person using the calculator assigns every finding. The calculator does the adding.

Limits of the calculation

It adds up points. It doesn't confirm or rule out a pulmonary embolism.
It's the original PESI from 2005, not sPESI.
It's the 11-variable point score.
Heart failure and chronic lung disease are separate items.
This page doesn't say what a score or class means or what to do with it.

Clinical decisions belong to a qualified clinician who knows the patient.

sPESI is the simplified version of the index. PESI adds age in years and gives each item its own weight.
PERC is a separate rule made of yes/no findings rather than weighted points. PESI is for a pulmonary embolism that has already been confirmed.

Glossary

Pulmonary embolism (PE): a blood clot that blocks an artery in the lungs.
Altered mental status: a change in alertness, orientation or thinking.
SpO2: oxygen saturation measured by a pulse oximeter.
Systolic blood pressure: the higher number in a blood pressure reading.

Common mistakes

Adding 1 point for age. Age is added as the number of years.
Giving heart rate 109 a point. The heart-rate item starts at 110.
Counting a systolic pressure of 100. The item needs a value under 100.
Rounding 35.9 °C up. The temperature item is for values under 36.
Combining heart failure and chronic lung disease. Each one adds 10 on its own.

Source

Aujesky D, Obrosky DS, Stone RA, et al. Derivation and validation of a prognostic model for pulmonary embolism. Am J Respir Crit Care Med. 2005;172(8):1041-1046. DOI: 10.1164/rccm.200506-862OC

Frequently asked questions

How do you calculate the PESI score?

Start with age in years. Add 10 for male sex, 30 for cancer, 10 each for heart failure and chronic lung disease, 20 each for heart rate of 110 or more, respiratory rate of 30 or more, temperature under 36 °C and SpO2 under 90%, 30 for systolic pressure under 100, and 60 for altered mental status.

What does a PESI score of 100 mean?

This page doesn't give an outcome by score or class. It adds up the points; what a score means depends on the person and the clinical context.

Is PESI the same as sPESI?

No. This calculator is the original PESI. sPESI is a separate, simplified score.

Why can the PESI score be over 100?

Age is added as a number of years, so an older person starts with a high total before any other item.

Who developed PESI?

Aujesky and colleagues, in a 2005 paper in the American Journal of Respiratory and Critical Care Medicine.