Initial distribution volume of glucose as noninvasive indicator of cardiac preload: comparison with intrathoracic blood volume

Objective: To analyze the correlation between initial distribution volume of glucose (IDVGI) and intrathoracic blood volume measured by single indicator dilution technique. Design and setting: Prospective clinical study conducted in the intensive care unit of a university hospital. Patients and methods: We enrolled 20 consecutive adult patients requiring hemodynamic monitoring with arterial pulse contour analysis system (PiCCO) and without any underlying pathology inducing generalized protein capillary leakage and/or marked peripheral edema. Cardiac output, intrathoracic blood volume, extravascular lung water were recorded. IDVGI was measured once per day for the first 5 days after PiCCO positioning by administering a bolus of 25 ml 20% glucose (5 g) over 30 s through a central venous catheter. The relationship between IDVGI and other variables was studied by regression analysis. Receiver operating characteristic curves were used to study the relationship between changes in IDVGI and changes in cardiac index, intrathoracic blood volume, and central venous pressure. Results: A good linear correlation was obtained between intrathoracic blood volume and IDVGI (R-2=0.79). Receiver operating characteristic curve analysis showed a good ability of initial distribution volume of glucose variations to reflect cardiac index variations. Conclusions: Our results indicate that IDVGI can serve as noninvasive indicator of cardiac preload.