What is the management of Acute Kidney Injury (AKI)?

From the Guidelines

For acute kidney injury (AKI) management, I recommend a comprehensive approach focusing on identifying and treating the underlying cause while supporting kidney function, as outlined in the KDIGO clinical practice guideline 1. First, ensure adequate hydration and blood pressure with IV fluids, typically isotonic crystalloids like normal saline at 10-20 ml/kg, unless the patient has volume overload, as suggested by the KDIGO guideline 1. Stop nephrotoxic medications including NSAIDs, aminoglycosides, and contrast agents. Monitor fluid balance, electrolytes, and kidney function with daily creatinine, BUN, and electrolyte measurements. Adjust medication dosages based on estimated GFR. For hyperkalemia, consider calcium gluconate (10 ml of 10% solution IV), insulin with glucose (10 units regular insulin with 50 ml of 50% dextrose), or sodium bicarbonate (50 mEq IV) for immediate management. Diuretics like furosemide may help manage fluid overload but won't improve kidney recovery. Renal replacement therapy (dialysis) is indicated for severe cases with refractory hyperkalemia, acidosis, uremia, or volume overload. Nutritional support should provide adequate protein (0.8-1.0 g/kg/day) while avoiding excessive nitrogen load, as recommended by the KDIGO guideline 1. Regarding the discontinuation of renal replacement therapy (RRT), a systematic review and meta-analysis found that numerous parameters, including traditional biochemical markers of kidney function and clinical findings such as urine output, can help identify patients for whom RRT may be safely discontinued 1. However, the decision to discontinue RRT should be based on individual patient assessment and the KDIGO recommendation that RRT should be discontinued “when it is no longer required, either because intrinsic kidney function has recovered to the point that it is adequate to meet patient needs, or because RRT is no longer consistent with the goals of care” 1.

Some key points to consider in AKI management include:

• Using isotonic crystalloids rather than colloids for initial management of expansion of intravascular volume in patients at risk for AKI or with AKI 1
• Using vasopressors in conjunction with fluids in patients with vasomotor shock with, or at risk for, AKI 1
• Avoiding the use of diuretics to prevent or treat AKI, except in the management of volume overload 1
• Providing nutritional support preferentially via the enteral route in patients with AKI 1
• Monitoring aminoglycoside drug levels when treatment with multiple daily dosing is used for more than 24 hours, or when treatment with single-daily dosing is used for more than 48 hours 1

From the Research

Definition and Diagnosis of Acute Kidney Injury (AKI)

• Acute kidney injury is a clinical syndrome characterized by a rapid decline in glomerular filtration rate and resultant accumulation of metabolic waste products 2.
• Severity of AKI is classified according to urine output and elevations in creatinine level 2.
• Etiologies of AKI are categorized as prerenal, intrinsic renal, and postrenal 2.

Management of AKI

• General management principles for AKI include determination of volume status, fluid resuscitation with isotonic crystalloid, treatment of volume overload with diuretics, discontinuation of nephrotoxic medications, and adjustment of prescribed drugs according to renal function 2, 3.
• Measures to prevent AKI include optimization of volume status and avoidance of nephrotoxic medications 3.
• Crystalloids are preferred over colloids for most patients, and hydroxyethyl starches should be avoided 3.
• Volume overload in the setting of AKI is associated with adverse outcomes, so attention should be paid to overall fluid balance 3.

Treatment and Supportive Care

• There are no targeted pharmacotherapies approved for the treatment of AKI 4, 3.
• The optimal timing of renal replacement therapy in critically ill patients with AKI is unclear, but is an area of active investigation 3.
• Supportive care measures may include optimizing nutritional status and glycemic control 2.
• Pharmacist-led quality-improvement programs reduce nephrotoxic exposures and rates of AKI in the hospital setting 2.
• AKI care bundles are associated with improved in-hospital mortality rates and reduced risk of progression 2.

Evaluation and Initial Management

• The evaluation and initial management of patients with AKI should include an assessment of the contributing causes of the kidney injury, an assessment of the clinical course including comorbidities, a careful assessment of volume status, and the institution of appropriate therapeutic measures designed to reverse or prevent worsening of functional or structural kidney abnormalities 5.
• The initial assessment of patients with AKI classically includes the differentiation between prerenal, renal, and postrenal causes 5.