Fig. 5

Effects of fluid and vasoactive agents on cardiovascular performance and the venous system. Figure reused with the permission of the Perioperative Quality Initiative (POQI). For permission requests, contact info@poqi.org. I Effect of volume loading on mean systemic filling pressure (Pmsf) and (un)stressed volume. Administration of a fluid bolus increases Pmsf (from Pmsf1 to Pmsf2, indicated respectively by position A (red dot) to B (green dot) on the pressure/volume curve). Unstressed volume remains constant while stressed volume increases. Total volume = unstressed + stressed increases, carrying a risk for fluid overload. See text for explanation. II Effect of venoconstriction and venodilation on mean systemic filling pressure (Pmsf) and (un)stressed volume. Venoconstriction increases Pmsf (from Pmsf1 to Pmsf2, indicated respectively by position A (red dot) to B (green dot) on the pressure/volume curve). Unstressed volume decreases while stressed volume increases. Total volume = unstressed + stressed remains constant, resulting in an auto-transfusion effect. Venodilation as seen in sepsis (vasoplegia) decreases Pmsf (from Pmsf1 to Pmsf3, indicated respectively by position A (red dot) to C (blue dot) on the pressure/volume curve). Unstressed volume increases while stressed volume decreases. Total volume = unstressed + stressed remains constant, resulting in an intravascular underfilling effect