Positive correlation between daily changes of initial distribution volume of glucose and cardiac output following subtotal esophagectomy

Introduction

We have reported that the initial distribution volume of glucose (IDVG) reflects the central extracellular fluid volume status and correlated with cardiac output following major surgery. In clinical practice we are using IDVG as an indicator of cardiac preload to predict hypovolemia or fluid refilling phase following major surgery. IDVG is an intermittent measurement parameter and its rather time consuming procedure limits frequent measurements of IDVG. In this study, to investigate whether or not continuous cardiac output (CO) monitoring could be used as a clinical alternative of IDVG to estimate the changes in cardiac preload, we examined a correlation between changes in CO and IDVG in sedated, mechanically ventilated postoperative patients.

Methods

Thirty-one patients with written informed consent managed in our ICU following subtotal esophagectomy ware included. IDVG was measured once a day from the day of admission in our ICU until 3rd postoperative day by injecting 5 g of glucose and calculated using a one-compartment model. CO was measured using a pulmonary artery catheter equipped with a continuous CO calculation computer. Regression analysis was used to detremine the relationship between daily differences in IDVG and CO.

Results

Trends of mean absolute values of IDVG and CO indicate parallel changes of the curves. Daily differences in IDVG and CO had a statistically significant correlation (r = 0.59, n = 93, P < 0.0001).

Conclusion

In sedated, mechanically ventilated patients following subtotal esophagectomy, changes of IDVG and CO had a good correlation. In this limited clinical setting, continuous CO monitoring could be used as an alternative of IDVG as a preload indicator although false positive error of changes in CO during the period of each IDVG measurement cannot be ruled out in our study design.