NEW YORK (Reuters Health) – Restricting fluids excessively during major abdominal surgery, even using an individualized “goal-directed fluid strategy,” increases the risk of hypovolemia and impairs organ function after surgery, suggest results of a randomized controlled study conducted in France.

In the study, fluid restriction was associated with “an increased incidence of postoperative complications such as an anastomotic leak and/or perianastomotic abscess (33%) and sepsis (44%),” the study team reports in the December issue of Archives of Surgery.

Dr. Emmanuel Futier, of the Department of Anesthesiology and Critical Care Medicine, Estaing Hospital, University Hospital of Clermont-Ferrand, Cedex, France, is first author on the paper. He told Reuters Health the key messages from this study could be the following.

One: “Fluid restriction should be administered cautiously during major surgery as there is a high risk of occult hypovolemia.”

Two: “Although fluid excess was found to be deleterious, the margin of safety with fluid restriction seems weak and requires careful monitoring.”

Three: “Individualized preload optimization and fluids alone may be not sufficient to ensure optimal tissue oxygenation.”

Adequate tissue perfusion is a key determinant of postoperative outcomes, complications and length of stay after surgery. Two concepts, in part contradictory, are proposed to manage fluids during surgery. One is fluid restriction and the other is goal-directed fluid therapy to optimize stroke volume and oxygen delivery.

In their study, Dr. Futier and colleagues aimed to integrate those concepts with the rationale that fluid restriction and an individualized preload optimization should represent the optimal strategy.

They randomly assigned 70 consecutive patients having major abdominal surgery to a restrictive fluid strategy (6 mL/kg/h of crystalloid) or a more conservative fluid strategy (12 mL/kg/h of crystalloid). Both groups received a fluid bolus when respiratory variation in peak aortic flow velocity was greater than 13%.

The clinicians observed that the incidence of complications overall, including postoperative anastomotic leak and sepsis, was significantly higher in the restrictive group than in the conservative group (all P < 0.05). The incidence of hypovolemia was also significantly higher in the restrictive group compared with the conservative group (P < 0.001). Compared with the more conservative fluid strategy, the restrictive fluid strategy also led to significantly lower mean perioperative and mean minimum central venous oxygen saturation levels (P = 0.02 and 0.04, respectively). In multivariate analysis, both hypovolemia and mean minimum central venous oxygen saturation were independently associated with anastomotic leak and sepsis. “Optimization of intravascular volume is a prerequisite to adequate tissue perfusion,” Dr. Futier noted, and “early detection and correction of potential tissue hypoxia triggers such as hypovolemia are fundamentally important.” The clinicians conclude, based on their study, that “excessively restrictive (fluid) strategies, particularly if unmonitored fixed regimens are used, should be applied cautiously to surgical patients.” Reference:
Conservative vs Restrictive Individualized Goal-Directed Fluid Replacement Strategy in Major Abdominal Surgery

Arch Surg 2010;145:1193-1200.