Question: What is renal replacement therapy?

Answer: Acute kidney injury occursin up to 50% of critically ill patients and is linked with high morbidity and mortality. Renal replacement therapy can rapidly correct life-threatening complications lined with acute kidney injury, like severe hyperkalemia, metabolic acidosis or pulmonary edema because of fluid overload. However, there is ambiguity regarding initiating renal replacement therapy in the presence of severe complications.

Question: Should renal replacement therapy be initiated early?

Answer: Early initiation of renal replacement therapy might lead to better control of metabolic dysfunctions and other complications linked with raised mortality, but may also unnecessarily expose patients to iatrogenic complications such as low blood pressure, bleeding, infection or hypothermia.

If the initiation of renal replacement therapy is intentionally delayed, it can allow for spontaneous renal function recovery, thus preventing the need for renal replacement therapy.

Question: What is the relationship between renal replacement therapy timing and clinical outcomes?

Answer: Results of a meta-analysis suggested an advantage of early renal replacement therapy; however, studies promoting early initiation included patients who received renal replacement therapy while not considering the patients with severe acute kidney injury who recovered kidney function without even receiving renal replacement therapy and hence are biased.

A delayed renal replacement therapy approach is reflected in a lesser number of patients receiving renal replacement therapy because renal recovery precludes the need for renal replacement therapy. Broader adoption of the delayed strategy may lead to lesser renal replacement therapy free days compared with those receiving early therapy.

Also, adverse events such as hyperkalemia, severe bleeding and severe cardiac rhythm disorder werenot common. There was an insignificant difference between their occurrence in early and delayed strategies. Hence, it can be concluded that delaying renal replacement therapy may be safe in the absence of life-threatening conditions.

Source

Gaudry SG, et al. Delayed versus early initiation of renal replacement therapy for severe acute kidney injury: a systematic review and individual patient data meta-analysis of randomised clinical trials. The Lancet. 2020; 395:1506-15.