6.1 Pre-operative
Patients may be exposed to contrast agents from clinical procedures prior to having their cardiac surgery. These are known to be nephrotoxic and would, therefore, involve a certain risk of developing contrast-induced AKI (CI-AKI). Newer iso-osmolar contrast agents that are less toxic can be used as an alternative for these procedures. Likewise, factors that alter renal perfusion should be identified and corrected. Nephrotoxic medications should be discontinued. If necessary, perioperative hydration and inotropic agents to improve cardiac output may be used. While intravenous isotonic crystalloid solution could lower CI-AKI risk, excess fluids may potentially cause harm and increase CI-AKI incidence. Whenever possible, renal recovery should be encouraged, and surgery should be delayed to prevent CS-AKI risk.42 Likewise, pre-operative anaemia is reported to be independently associated with postoperative AKI and should thereby be avoided and managed appropriately before surgery.27