This has been asked about in Question 12 from the first paper of 2010 and Question 5 from the first paper of 2003.
Specifically, " Briefly outline the relationship between dose of dialysis and outcome"
The 2010 question makes reference to the following "relevant studies":
Since then, there have been a few more:
In summary:
Higher intensity renal replacement therapy does not reduce mortality rates or improve renal recovery among patients with AKI.
There is no evidence to recommend a dose in excess of 25ml/kg/hr.
It seems beyond a certain dose, renal replacement therapy removes as many useful molecules as it does toxins, and the benefit from escalating the dose deteriorates.
In detail:
So, though small trials occasionally found a mortality benefit, large well-designed studies were unable to detect one. At this stage, the issue could be said to have been put to rest. Subsequent investigators have made attempts to find subtle non-survival benefits, or to investigate higher dialysis doses in patients with sepsis. More negative trials ensued.
Ronco, Claudio, et al. "Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: a prospective randomised trial." The Lancet 356.9223 (2000): 26-30.
Saudan, P., et al. "Adding a dialysis dose to continuous hemofiltration increases survival in patients with acute renal failure." Kidney international 70.7 (2006): 1312-1317.
Bouman, Catherine SC, et al. "Effects of early high-volume continuous venovenous hemofiltration on survival and recovery of renal function in intensive care patients with acute renal failure: a prospective, randomized trial." Critical care medicine 30.10 (2002): 2205-2211.
Tolwani, Ashita J., et al. "Standard versus high-dose CVVHDF for ICU-related acute renal failure." Journal of the American Society of Nephrology 19.6 (2008): 1233-1238.
VA/NIH Acute Renal Failure Trial Network. "Intensity of renal support in critically ill patients with acute kidney injury." The New England journal of medicine359.1 (2008): 7.
Bellomo, R., et al. "Intensity of continuous renal-replacement therapy in critically ill patients." The New England journal of medicine 361.17 (2009): 1627-1638.
Jun, Min, et al. "Intensities of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis." Clinical Journal of the American Society of Nephrology 5.6 (2010): 956-963.
Zhang, Ping, et al. "Effect of the intensity of continuous renal replacement therapy in patients with sepsis and acute kidney injury: a single-center randomized clinical trial." Nephrology Dialysis Transplantation 27.3 (2012): 967-973.
Vesconi, Sergio, et al. "Delivered dose of renal replacement therapy and mortality in critically ill patients with acute kidney injury." Crit Care 13.2 (2009): R57.
Van Wert, Ryan, et al. "High-dose renal replacement therapy for acute kidney injury: systematic review and meta-analysis." Critical care medicine 38.5 (2010): 1360-1369.
Joannes-Boyau, Olivier, et al. "High-volume versus standard-volume haemofiltration for septic shock patients with acute kidney injury (IVOIRE study): a multicentre randomized controlled trial." Intensive care medicine 39.9 (2013): 1535-1546.
Clark, Edward, et al. "High-volume hemofiltration for septic acute kidney injury: a systematic review and meta-analysis." Critical Care 18.1 (2014): R7.
Clark, Edward G., and Sean M. Bagshaw. "Unnecessary Renal Replacement Therapy for Acute Kidney Injury is Harmful for Renal Recovery." Seminars in dialysis. Vol. 28. No. 1. 2015.
Zhang, Ping, et al. "Effect of the intensity of continuous renal replacement therapy in patients with sepsis and acute kidney injury: a single-center randomized clinical trial." Nephrology Dialysis Transplantation 27.3 (2012): 967-973.