| Popis: |
Summary Current mathematical descriptions of fluid and blood component kinetics are limited. Many apply only to steady-state conditions or to limited parts of physiology. The blood conservation models assume normovolemia in the face of operative blood loss. Although limited, current models appear to provide acceptable guidelines for blood conservation practices. The end points and procedures for conserving blood will certainly evolve over time. More will be learned about the physiology of fluid and blood administration and loss. Mathematical models can provide quantitative guidance to safely performing conservation procedures and reaching end points. Although an understanding and application of kinetic principles to blood and fluid replacement therapy should lead to more efficient restoration or maintenance of normal concentrations and volumes, these are only partial goals. In the case of drugs, while achieving therapeutic drug level is an important goal, the possibility of variability in pharmacodynamics cannot be ignored. Likewise, stored and re-infused RBCs and platelets may not have normal “concentration-effect” curves. If this turns out to be true, than achieving normal concentrations and volumes may not be the right end point. |
