Management of AKI: Fluids

Acute kidney injury (AKI) significantly impacts critically ill patients, increasing morbidity, mortality, and healthcare costs. The incidence of AKI in intensive care units (ICUs) has risen, affecting over 50% of patients, particularly among older individuals with multiorgan failure. While traditional approaches emphasize fluid resuscitation to ensure renal perfusion, recent evidence challenges its efficacy, revealing AKI patients’ susceptibility to volume overload. This chapter reviews fluid management in critically ill AKI patients, emphasizing the delicate balance required between adequate resuscitation and preventing volume overload. The interplay of factors influencing renal perfusion is discussed, including renal blood flow, vascular resistance, and the impact of hypotension and venous congestion. Clinical evaluation strategies for AKI in the ICU setting, considering that the most frequent causes of AKI are consequences of hemodynamically mediated reductions in the glomerular filtration rate, are explored. Then, the chapter delves into studies examining the association between fluid therapy and AKI, addressing volume and type of fluid. In the context of fluid type, the debate between crystalloids and colloids is scrutinized, with a focus on recent trials comparing their impact on AKI patients. The preference for balanced crystalloids is highlighted, and chloride-rich solutions might be an option in the case of hypochloremia. The chapter concludes by emphasizing a cautious and systematic approach to fluid management in AKI, with careful assessment and reassessment of the volume and hemodynamic status, promoting the use of balanced crystalloids in cases of hypovolemia and avoiding fluid overload.