From the Guidelines
To handle an acute kidney injury (AKI), first identify and address the underlying cause while optimizing hemodynamics and volume status, and consider the use of isotonic crystalloids for initial management of expansion of intravascular volume, as suggested by the KDIGO clinical practice guideline 1. The management of AKI involves a multifaceted approach that includes discontinuing nephrotoxic medications, ensuring adequate hydration, monitoring fluid balance and electrolytes, and adjusting medication dosages based on estimated GFR. Some key considerations in the management of AKI include:
- Discontinuing nephrotoxic medications, including NSAIDs, aminoglycosides, and contrast agents
- Ensuring adequate hydration with intravenous fluids, typically isotonic crystalloids like normal saline, if the patient is hypovolemic, but avoiding fluid overload
- Monitoring fluid balance, daily weights, and intake/output carefully
- Checking electrolytes, BUN, and creatinine regularly, correcting abnormalities as needed, particularly hyperkalemia, which may require urgent treatment with calcium gluconate, insulin with glucose, or sodium bicarbonate
- Adjusting medication dosages based on estimated GFR
- Considering renal replacement therapy (dialysis) for refractory hyperkalemia, volume overload, severe acidosis, uremic symptoms, or certain toxin ingestions
- Providing nutritional support while limiting protein in severe cases The management approach varies based on AKI staging (1-3) and whether the etiology is prerenal (circulation problems), intrinsic (kidney damage), or postrenal (outflow obstruction). Early nephrology consultation is recommended for severe or complex cases, especially when dialysis might be needed, as suggested by the KDIGO clinical practice guideline 1. Additionally, the use of vasopressors in conjunction with fluids may be considered in patients with vasomotor shock with, or at risk for, AKI, as suggested by the KDIGO clinical practice guideline 1. However, the optimal timing for liberation from renal replacement therapy in critically ill patients is still a topic of ongoing research, and a systematic review and meta-analysis found that numerous parameters have been evaluated to help identify patients for whom RRT may be safely discontinued, including traditional biochemical markers of kidney function and clinical findings such as urine output 1.
From the Research
Handling Acute Kidney Injury (AKI)
To handle AKI, several key aspects of management must be considered, including:
- Treating the underlying cause of AKI
- Supportive care through fluid management, vasopressor therapy, and kidney replacement therapy (KRT) 2
- Management of blood pressure, with targets often being higher in AKI patients, achievable through fluids and vasopressors 2
- Consideration of the timing of KRT initiation, with controversy surrounding early start dialysis 2
Fluid Management in AKI
Fluid management is crucial in AKI patients, with the following considerations:
- Volume resuscitation as a cornerstone in treating hemodynamic instability 3
- Preference for crystalloids over synthetic colloids due to the latter's association with increased risk of AKI 3
- Aiming for neutral or slightly negative fluid balance, rather than hypervolemia, which is increasingly shown to be detrimental to renal outcomes and survival 3, 4
- Use of conservative fluid strategies, diuretics, or renal replacement therapy to achieve fluid balance and minimize complications 3, 4
Evaluation and Management of AKI
Initial evaluation and management of AKI involve:
- Laboratory work-up
- Medication adjustment
- Identification and reversal of the underlying cause
- Referral to appropriate specialty care 5
- Consideration of a 3-phase model of fluid management in critically ill patients with AKI, incorporating early goal-directed fluid therapy and conservative late fluid management 6