Relationship among the heart, vasculature and blood volume at perioperative period: The influence of volatile anesthetics

Ventricular pressure-volume relationship enables us to understand the relationship among the heart, vasculature, and blood volume, since it provides, on a single plane, the preload, afterload, and cardiac contractility, which are major determinants of stroke volume. In addition, it is also possible to estimate cardio-vascular matching, namely the optimum of cardio-vascular interaction, by an analysis of ventricular pressure-volume relationship. Volatile anesthetics cause circulatory depression due primarily to decreases in cardiac contractility and stressed blood volume. The optimal treatment for it is to restore these decreases produced by volatile anesthetics. Thus, an increase in afterload by vasoactive agents may cause deterioration of cardio-vascular matching. A rationale for optimal perioperative circulatory management can be deduced from understanding a quantitative interaction among the heart, vasculature, and blood volume.