If you happen to be someone who has tried to memorize the Alveolar Gas Equation, Osmolal gap, or sodium-glucose correction formula more than once, you probably should be carrying the ICE Card.

It is an "Intensive Care Equation" card made of indestructible polyvinyl. Tables on the ICE Card list the normal values for hemodynamic pressure monitoring and flow-related parameters, renal equations and ventilatory equations.