In patients undergoing major abdominal surgery, optimal perioperative fluid management remains challenging, according to researchers. Adequate tissue perfusion is an essential component of oxygenation and can improve postoperative outcomes. Perioperative fluid management includes 2 primary, partially overlapping strategies: (1) fluid substitution using unmonitored fixed regimens and estimations of fluid losses (and suggesting high or low volumes of fluids) and (2) goal-directed fluid therapy (GDT) based on the maximization of flow-related parameters. GDT has been shown to improve patient outcomes and reduce in-hospital stays compared with conventional fluid replacement. In theory, GDT, based on the maximization of flow-related parameters, hypovolemia and fluid overload could be prevented because the administration of fluids is stopped when the applied parameter is maximized. Although targeting indicators of early tissue hypoxia such as central venous oxygen saturation (ScvO2) may aid in the management of surgical patients, the effects of various fluid strategies on perioperative ScvO2 are unknown. Researchers conducted a prospective, randomized trial to compare the influence of 2 volumes of fluid, integrated with GDT, on hypovolemia and ScvO2 and to assess their relationships with postoperative morbidity. They reported study results in Archives of Surgery [2010;145(12):1193-1200]. The study cohort included 70 consecutive patients undergoing major abdominal surgery. The patients were randomly assigned to a restrictive fluid strategy (6 mL/kg/h of crystalloid; R-GDT) or a more conservative fluid strategy (12 mL/kg/h; C-GDT). A fluid bolus was administered in both groups when respiratory variation in peak aortic flow velocity was >13%. Postoperative complications were recorded for all patients. The primary outcome measures were overall incidence of postoperative complications, especially anastomotic leak and sepsis. Baseline characteristics were similar for both groups. Surgical procedures were equally distributed between the 2 groups and included colon or rectal resections (43%, n=33 patients), duodenopancreatectomy (20%, n=14 patients), gastrectomy (21%, n=15 patients), and hepatectomy (16%, n=11 patients). All patients were extubated within 2 hours following surgery. In the C-GDT group, the total mean volume of fluids perfused was greater than in the R-GDT group (1.22 vs 7.7 mL/kg/h, respectively; P<.001). The mean incidence of intraoperative hypovolemia was higher in the R-GDT group than in the C-GDT group (3.8 vs 1.2; P<.001). The patients in the R-GDT group required more colloid fluid than patients in the C-GDT group (mean volume, 854 vs 316 mL, respectively; P<.001). There was no difference between the 2 groups in intraoperative blood loss, need for blood transfusion, need for vasoactive or inotropic support, or the principal hemodynamic and biologic variables. The overall incidence of complications was higher in the R-GDT group compared with the C-GDT group (58% vs 36%, respectively; P<.007). The R-GDT group had greater incidence of anastomotic leak and/or perianastomotic abscess (12 vs 4, respectively; P=.03) and postoperative sepsis (16 vs 5, respectively; P=.007). There was no difference in rates of reintervention, wound abscess, pneumonia, or urinary tract infection. There was an increase in the number of patients with hypovolemia in the R-GDT group compared with the C-GDT group (P<.001). The C-GDT group had higher perioperative mean ScvO2 compared with the R-GDT group (81.1% vs 78.9%, respectively; P=.02) and mean minimum ScvO2 (72% vs 69%, respectively; P=.04). Univariate analysis revealed 4 variables associated with anastomotic leak and/or perianastomotic abscess and sepsis: intraoperative hypovolemia (P=.004), group (P=.007), mean minimum ScvO2 (P=.003), and body mass index (P=.02).