Fluid management in perioperative and critically ill patients

Fluid therapy to restore and/or maintain tissue perfusion may affect patient outcomes in perioperative, emergency, and intensive care. Kinetic analyses and outcome-oriented studies have provided more insight into fluid management. Crystalloids are slowly distributed to the interstitial space, and the efficiency (proportion of infused fluid retained in the bloodstream) is 50%−75% as long as infusion continues and may increase up to 100% when the arterial pressure has decreased. Elimination of the infused fluid during general anesthesia and surgery is very slow, amounting to only 10%–20% compared with that in conscious patients. When the endothelial glycocalyx layer is degraded in sepsis or trauma-induced systemic inflammation, turnover of colloids and crystalloids is accelerated and the efficiency is reduced, which may lead to tissue edema, inflammation, poor wound healing, and organ dysfunction. Balanced crystalloids are pragmatic initial resuscitation fluids and improve patient outcomes compared to saline (0.9% sodium chloride). Albumin may be beneficial, but other synthetic colloids appear to increase the risk of acute kidney injury and death among patients in the intensive care unit. Fluid kinetics is likely to change based on patient physiological conditions (e.g., general anesthesia, surgery, stress, dehydration, blood pressure, or inflammation) and fluid types. To maximize efficacy and minimize iatrogenic side effects, fluids should be prescribed based on individual patient factors, disease states, and other treatment remedies.