In a patient, optimizing oxygen delivery has more options than manipulating
oxygen demand. To optimize oxygen delivery, one should break down the
components of the DO2 equation:
DO2= Cardiac Ouput [(1.34 x Hgb x O2 sat) + (PO2 x 0.003) ]
DO2= Cardiac Output [ Bound O2 + Dissolved O2]
For practical purposes, one should ignore the contributions of “ dissolved
O2”, since it is multiplied by a factor of 0.003. Increasing hemoglobin (transfusion)
when one is anemic and optimizing oxygen saturation (oxygenation maneuvers)
increase the number of “trucks” and the amount of beer in the trucks for delivery to
Green Bay. Optimizing cardiac output CO requires manipulation of the
components of cardiac output.
Stroke volume is affected by preload (volume status) afterload (systemic
vascular resistance) and contractility (inotropic characteristics). Recall, however,
that contractility of the heart is also dependent on the preload as depicted by the
Frank Starling curve.