Use Oxygenation Index OI when you need to compute the oxygenation index as mean airway pressure x FiO2 x 100 divided by arterial oxygen tension. Enter Mean airway pressure, Inspired oxygen fraction, and Arterial O2 using the definitions and units below so the result can be reproduced.

Mean airway pressure

A finite measured or assumed value, expressed in cmH2O.

Inspired oxygen fraction

A finite measured or assumed value from 0 through 1.

Arterial O2

A finite measured or assumed value, expressed in mmHg.

The published tool contract uses this rule: Compute the oxygenation index as mean airway pressure x FiO2 x 100 divided by arterial oxygen tension.^[1]

Oxygenation index

The calculated oxygenation index.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small. Inspired oxygen fraction must remain between 0 and 1.

Retain the original Mean airway pressure, Inspired oxygen fraction, and Arterial O2 values and their units alongside the result. OI Variant With PEEP is useful when you instead need to compute an oxygenation index variant as mean airway pressure times the inspired oxygen percentage divided by arterial oxygen tension, without a scaling factor of 100. Cardiac Index provides another view by helping you compute cardiac index as cardiac output divided by body surface area.

• OI Variant With PEEP

  Compute an oxygenation index variant as mean airway pressure times the inspired oxygen percentage divided by arterial oxygen tension, without a scaling factor of 100.

• Cardiac Index

  Compute cardiac index as cardiac output divided by body surface area.

• Drought Tolerance Index

  Compute the drought tolerance index as stressed yield divided by control yield times one hundred.