The management of acute kidney injury (AKI) in the intensive care unit (ICU) involves several key considerations:
Risk assessment
- Patients should be stratified for risk of AKI according to their susceptibilities, especially preexisting proteinuria and chronic kidney disease (CKD), and exposures to nephrotoxic medications or interventions
- The patient's age, preoperative renal dysfunction, cardiac dysfunction, use of RAAS inhibitors, and duration of cardiopulmonary bypass are considered risk factors for AKI
- Hospital-acquired AKI has a worse survival prognosis than community-acquired AKI, and septic AKI has a higher mortality than non-septic AKI
Fluid management
- Controlled fluid resuscitation should be initiated in true or suspected volume depletion
- Isotonic crystalloids are recommended for volume expansion in patients with AKI in the absence of hemorrhagic shock
- Balanced crystalloids are preferred over isotonic saline in patients with AKI
Hemodynamic monitoring
- The physiological status of the patient should be promptly assessed after identification of AKI or recognition of high risk for it
- Additional monitoring is recommended in patients with persistent AKI to reevaluate hemodynamic and volume status, adequacy of kidney perfusion, and to identify complications of AKI, such as fluid overload, acidosis, and hyperkalemia
General principles
- Therapeutic drug dosing should be adjusted to altered kinetics in AKI
- Regular reevaluation of drug dosing is necessary as renal function changes and as renal support is initiated, altered, or discontinued
- A documented review of all medications in patients at risk of or with identified AKI is recommended to withhold medications likely to adversely affect renal function
Renal replacement therapy (RRT)
- RRT is deployed to address metabolic dysfunction and volume excess until kidney function recovers in patients with severe AKI
- The optimal time to initiate RRT to improve clinical outcomes remains uncertain
In conclusion, the management of acute kidney injury in the ICU involves careful risk assessment, appropriate fluid management, vigilant hemodynamic monitoring, adjustment of therapeutic interventions, and consideration of renal replacement therapy when necessary. Early identification and intervention can improve patient outcomes, and tailoring the management to the individual patient's needs is essential.