DETERMINATION OF TOTAL EFFECTIVE VASCULAR COMPLIANCE IN PATIENTS WITHSEPSIS SYNDROME

Changes in capacitance vessels have important consequences on cardiac filling pressure and fluid volume distribution in patients with sepsis syndrome. Vascular compliance may be evaluated from the slope of the relationship between changes in total blood volume (Delta TBV) and cha nges in central venous pressure (Delta CVP) during acute volume expans ion (450 mi of gelatin fluid over 6 min), i.e., from the Delta TBV/Del ta CVP ratio. The mean ratio (mi x mm Hg-1 x kg(-1)) was 2.03 +/- 0.21 in control subjects, 1.43 +/- 0.25 in mechanically ventilated patient s without sepsis syndrome, and 0.94 +/- 0.24 in mechanically ventilate d patients with sepsis syndrome (p < 0.0001 versus the other two group s). Based on echocardiographic determinations, cardiac performance was constantly found within the normal range (cardiac output ranged from 5.6 +/- 1.2 to 6.7 +/- 2.0 L/min in nonseptic patients from 6.8 +/- 1. 9 to 7.8 +/- 2.2 in septic patients). Effective compliance of the tota l vascular bed is therefore reduced in patients with sepsis syndrome, independently of the hemodynamic modifications due to mechanical venti lation.