This chapter tries to satisfy the requirements of Section H1(viii) from the 2017 CICM Primary Syllabus, which expects the exam candidate to "describe the physiological effects of renal dysfunction". It has been asked about in Question 19 from the second paper of 2012, as well as Question 1 from the first Fellowship Exam paper of 2011. The First Part exam question specifically asked about "the changes that occur in the plasma with renal dysfunction". The college comments for this question were characteristically brief and unenlightening, but at the end did mention that "It was expected that some mention of changes in electrolytes (e.g.Na+, K+, Ca2+), HCO3, PO4, hormones (1, 25 vitamin D, erythropoietin), proteins, etc. be included." In short, the question really wanted only biochemistry. In contrast, the Part Two exam question asked for everything, and the college model answer was so good that the author had no choice but to reproduce it below, with minimal modification.
Biochemical changes associated with renal failure, in brief summary, are:
The best reference for this actually ended up being Wills (1968), which is as ancient as the bedrock, but still relevant for the same reason that kidneys themselves are still relevant (i.e that they and their failure have not changed markedly in the last hundred thousand years).
Overall, the physiological changes associated with renal failure could be summarised as follows:
Metabolic and Endocrine:
Polyneuropathy and myopathy
To this, one might add a note regarding nutrition. A normal or slightly increased daily protein intake may be required to compensate for amino acid losses into the circuit, and for the hypercatabolic state of critical illness. In contrast, intermittent haemodialysis patients tend to benefit from low protein and low sodium diet so as to decrease their urea load.
LITFL take this answer, and build wonderfully upon it. Specifically, they quote an editorial by Szamosfalvi and Yee (2013), which is the single most useful published resource on this topic.
Issues specific to ESRD raised in this article include:
The all-cause in-ICU mortality of ESRD patients admitted to ICU seems to be over double that of patients without renal failure (11% vs 5%), though it is lower than the mortality of patients with acute renal failure (23%).
Clermont, Gilles, et al. "Renal failure in the ICU: comparison of the impact of acute renal failure and end-stage renal disease on ICU outcomes." Kidney international 62.3 (2002): 986-996.
Szamosfalvi, Balazs, and Jerry Yee. "Considerations in the critically ill ESRD patient." Advances in chronic kidney disease 20.1 (2013): 102-109.
Arulkumaran, N., N. M. P. Annear, and M. Singer. "Patients with end-stage renal disease admitted to the intensive care unit: systematic review." British journal of anaesthesia 110.1 (2013): 13-20.
Thompson, Stephanie, and Neesh Pannu. "Renal replacement therapy in the end-stage renal disease patient with critical illness." Blood purification 34.2 (2012): 132-137.
Wills, M. R. "Biochemical consequences of chronic renal failure: a review." Journal of clinical pathology 21.5 (1968): 541.