Fluid Management in Acute Kidney Injury

The goal of fluid therapy in critical care medicine is to restore hemodynamic stability and vital organ perfusion while avoiding interstitial edema. Acute kidney injury (AKI) is a common complication in critically ill patients. Decisions regarding fluid management in critically ill patients with AKI are difficult, as these patients often have accompanying oliguria as well as body fluid overload. Both hypovolemia and volume overload are associated with increased morbidity and mortality in critical care patients; therefore, accurate assessment of the intravascular volume status as well as the response to fluid replacement remains one of the most challenging and important issues for clinicians in daily practice. Newer dynamic preload indexes, such as stroke volume variation and pulse pressure variation in conjunction with the end-expiratory occlusion test and the passive leg-raising test, have been shown to be more reliable indicators for accurate evaluation of fluid responsiveness in critically ill patients than static pressure measurements, such as central vein pressure and pulmonary artery occlusion pressure. In patients with established AKI who are unresponsive to fluid administration, fluid restriction is the treatment of choice. When fluid therapy is indicated for AKI patients, isotonic crystalloids should be the preferred agents in the absence of hemorrhagic shock. Balanced solutions may reduce the risk of hyperchloremic acidosis and kidney injury. In summary, volume management is an integral part of the care of critically ill patients with AKI. An optimal strategy might involve a timely period of guided fluid resuscitation with appropriate solutions, followed by an appropriate fluid balance.