Acute kidney injury and chronic kidney disease fluid management and electrolyte disorder control
Fluid and electrolyte management in AKI should be directed to correction of immediately life-threatening abnormalities and to prevention of worsening volume overload or solute complications. Specialist escalation for renal replacement therapy (RRT) should occur when hyperkalaemia, metabolic acidosis, uraemic complications, or fluid overload persist despite medical management. [1]
Fluid balance principles in acute kidney injury
- Hourly urine output measurement can be useful early after initial fluid resuscitation until intravascular volume is restored. [2]
- After volume is restored, hourly urine output should not be used as a primary target for further fluid management because urine output can become an unreliable indicator of kidney perfusion during AKI. [2]
- Loop diuretics can be considered to treat fluid overload or oedema while awaiting RRT or while renal function is recovering in patients not receiving RRT. [1]
Renal replacement therapy triggers for solute and fluid disorders
- Immediate referral and discussion for RRT initiation should occur when any of the following are not responding to medical management: hyperkalaemia, metabolic acidosis, symptoms or complications of uraemia (for example pericarditis or encephalopathy), fluid overload, or pulmonary oedema. [1]
- The decision to start RRT should be based on the patient’s overall condition rather than an isolated urea, creatinine, or potassium value. [1]
Hyperkalaemia management in acute kidney injury and chronic kidney disease
- Emergent hyperkalaemia management should follow a stepwise approach that rapidly stabilizes the myocardium and removes potassium from the body. [3]
- Stable patients with mild to moderate hyperkalaemia should undergo hospital assessment when acutely unwell and particularly in the presence of AKI. [3]
- Nonemergent hyperkalaemia management in CKD should include correction of correctable factors, including severe metabolic acidosis, and structured consideration of diet and medications that contribute to hyperkalaemia. [4]
- Food-based potassium restriction should be individualized in CKD G3–G5 in the setting of emergent hyperkalaemia and should be supported by dietitian or accredited nutrition provider assessment. [4]
- For people with CKD G3–G5 with a history of hyperkalaemia, advice should include limiting foods rich in bioavailable potassium (for example processed foods) as a prevention strategy during periods of increased hyperkalaemia risk. [4]
Metabolic acidosis management
- Metabolic acidosis should be treated as an indication for escalation when it is not responding to medical management. [1]
- CKD hyperkalaemia management should account for the role of correction of severe metabolic acidosis as a correctable factor within a systematic approach. [4]
Monitoring and transition planning after acute kidney injury
- Serum creatinine should be monitored after an episode of AKI with monitoring frequency based on stability and degree of renal function at the time of discharge. [1]
- Referral consideration after recovery from AKI should include eGFR thresholds (for example eGFR 30 mL/min/1.73 m² or less in adults). [1]
Common clinical sequencing errors to avoid
- Over-reliance on urine output as a primary target after intravascular volume restoration should be avoided because urine output may become an unreliable measure of kidney perfusion during AKI. [2]
- Deferring evaluation for RRT in the setting of persistent hyperkalaemia, persistent metabolic acidosis, uraemic complications, or persistent fluid overload despite medical management should be avoided. [1]
- Treatment decisions for RRT should not be based on isolated laboratory values without integration of the patient’s overall clinical condition. [1]
Goals of therapy
- The goals of AKI fluid and electrolyte management are prevention of cardiac arrhythmia and other life-threatening complications from hyperkalaemia, mitigation of complications from metabolic acidosis, and control of fluid overload to avoid pulmonary oedema. [1]
- The overarching CKD goals in hyperkalaemia management are reduction of recurrent hyperkalaemia risk using individualized dietary and pharmacologic strategies and correction of correctable contributors such as metabolic acidosis. [4]