Perioperative changes in the circulatory blood volumes in patients undergoing the abdominal aortic aneurysm repair

Background: The effect of the intraoperative volume load on the circulating blood volume is unclear. Therefore, we investigated the changes of the perioperative blood volume in patients undergoing major surgery. Methods: In 16 patients undergoing abdominal aortic aneurysm repair, we measured the circulating blood volume (BV · kg^-1) with the pulse dye-densitometry method (DDG analyzer) before operation, just after operation, on the first postoperative day (IPOD) and 2POD. Anesthesia was maintained with general anesthesia and epidural analgesia. The volume of infusion depended on empiric judgment by an anesthesiologist. Results: Mean anesthesia time was 390 minutes, the mean volume of infusion 4225 ml, transfusion 1329 g, blood loss 1567 g, urine output 729 ml, and mean water balance +3287ml. The mean body weight (BW) was 59.2 ± 13.7 (before), 60.2 ± 14.4 (just after), 60.5 ± 14.3 (IPOD), and 60.3 ± 14.3 (2POD) kg, respectively. The mean BV · kg^-1 was 78.0 ± 19.0 (before), 65.6 ± 13.4 (just after), 70.4 ± 15.7 (IPOD), and 76.5 ± 18.2 (2POD) ml · kg^-1, respectively. The mean BW after operation increased significantly from the value before surgery. However, the mean BV · kg^-1 decreased significantly. There was a significant correlation between the intraoperative increase in BW and intraanesthetic water balance (Y = -2.91 + 0.071X; R = 0.66, P = 0.0412), but there was no significant correlation between the change in BV · kg^-1 and intraanesthetic water balance. Conclusions: Intraoperative water balance influenced a change of BW significantly, but did not affect BV · kg^-1.