A linear approximation of Brody's equation to predict oxygen consumption in adult humans

Objective. The objective of our study was to derive a linear approximation to Brody's equation for oxygen consumption as a simpler alternative for the clinician. Methods. The approximation was derived by using calculus to construct a line tangent to Brody's equation at 81 kg. Results. The linear approximation was derived to be: {Mathematical expression} where w is the subject's weight in kilograms. The error introduced by this linear approximation is 10.9% at 30 kg and 1.35% at 120 kg. Conclusions. This linear equation may have utility for approximating oxygen consumption when an approximation is required, as in closed circuit anesthesia. The utility of this equation is that it is linear and produces a result similar to Brody's equation.