The evaluation of hemodynamics in post thoracic esophagectomy patients

Thoracic esophagectomy is one of the most invasive operations, and it is necessary to have a precise understanding of postoperative hemodynamics in order to maintain normal circulation. PiCCO (pulse contour cardiac output, Pulsion Medical Systems; Munich, Germany), a new technique based on an arterial thermodilution technique, allows the measurement of intra-thoracic blood volume index (ITBVI), which has been reported to be a useful parameter for cardiac preload. In this study, changes of ITBVI were analyzed after thoracic esophagectomy using the PiCCO system. Simultaneously, the patient's circulating blood volume (cBV) and cardiac index (CI) were measured using dye densitometry and the relation between the CI and ITBVI was evaluated.

The PiCCO system was introduced in 20 patients immediately after thoracic esophagectomy, and circulatory parameters such as central venous pressure (CVP), and ITBVI were measured on ICU Days (ICUD) 1, 2 and 3. cBV and CI were simultaneously measured using the Dye Densitogram (DDG) Analyzer System (Nihon Koden, Tokyo, Japan).

The mean fluid balance during the operation was 3462 +/- 1341mL. CI was 3.8 +/- 0.7L/min/m2 on ICUD 1, 4.4 +/- 0.8L/min/m2 on ICUD 2, and 4.3 +/- 1.OL/ min/m2 on ICUD 3, and postoperative hemodynamics were well maintained. The ITBVI (normal range: 850-1000mL/m2) was also well controlled with 977 +/- 216mL/m2 on ICUD 1, 1061 +/- 221mL/m2 on ICUD 2, and 1043 +/- 151mL/m2 on ICUD 3, respectively, although BV ratio (measured cBV / Japanese standard cBV based on height and weight) was less than 1.0 during the same period. Additionally, ITBVI had better correlation with CI (r = 0.559, p = 0.003) compared with CVP (r = 0.036, p = 0.861).

Following thoracic esophagectomy, ITBVI was maintained within the normal range, in spite of a decrease in cBV. There was a correlation between ITBVI and CI, indicating that ITBVI might be a useful parameter for cardiac preload.