Perioperative fluid management: progress despite lingering controversies.

Perioperative fluid management remains controversial. Nevertheless, its optimization is essential to reducing the risk of postoperative complications, which have been shown to profoundly affect patients' short- and long-term outcomes. Current evidence favors a "flow-guided" approach to perioperative fluid administration, which uses variables such as stroke volume and cardiac output as the basis for guiding fluid requirements. The optimal fluid is controversial, although colloids appear to have some physiologic advantages over crystalloids. Minimally invasive technologies have emerged for intraoperative monitoring of blood flow, which may enable more precise fluid titration.