Intraoperative fluid restriction improves outcome after major elective gastrointestinal surgery

Fluid therapy is one of the most controversial topics in perioperative management. There is continuing debate with regard to the quantity and the type of fluid resuscitation during elective major surgery. However, there are increasing reports of perioperative excessive intravascular volume leading to increased postoperative morbidity and mortality. Recent evidence suggests that judicious perioperative fluid therapy improves outcome after major elective gastrointestinal surgery. The observed benefits may not be solely attributable to crystalloid restriction but also to the use of colloids instead. Some clinically useful guidelines based on the studies discussed in this review include avoidance of deep general anesthesia and elimination of preload for patients who receive epidural analgesia. A balanced approach to fluid management is recommended, with colloids administered to provide hemodynamic stability and maintain urine output of 0.5 mL · kg^-1 · h ^-1 and crystalloids administered only for maintenance. In addition, blood loss may be replaced with colloid on a volume-to-volume basis. Furthermore, predetermined algorithms that suggest replacement of third space losses and losses through diuresis are unnecessary. Significant reduction in crystalloid volume can be achieved without encountering intraoperative hemodynamic instability or reduced (i.e., < 0.5 mL · kg^-1 · h^-1) urinary output just by avoiding replacement of third space losses and preloading. Finally, there is a need for well-controlled studies in a well-defined patient population using clear criteria or endpoints for perioperative fluid therapy.