Outline  the  pathophysiological   changes  associated  with  end-stage  kidney disease (dialysis dependent) that may impact on the management of critically ill patients.

[Click here to toggle visibility of the answers]

College Answer

Renal:
•    Low/no urine output
Metabolic and Endocrine:
•     Associated
o   Hyperkalaemia
o   Abnormal Ca++
o   Hyperphosphataemia
Need for dialysis determines fluid prescribing, feeding and any protein restriction
Cardiovascular:
•    Hypertension very common
•    Atherosclerosis common
•    Pericarditis common
Respiratory:
•    Prone to pulmonary oedema
Neurological:
•    Dialysis disequilibrium
Polyneuropathy and myopathy
Skin:
•    Fragile skin
Haematological:
•     Anaemia
•    Platelet dysfunction
Gastrointestinal:
•    Impaired gastrointestinal motility
•    Increased risk of bleeding related to gastric ulceration
Immunological:
•    Increased risk of infection
Pharmacological:
•    Altered clearance of medications that have predominant renal excretion
Vascular access:
•    Fistulas used for dialysis may complicate CVC and arterial access

Discussion

The college answer to this question is a systematic approach which the clever candidate will model. All one can do is rearrange the college response into a different frame.

B) Respiratory considerations:

  • Tendency towards pulmonary oedema

C) Cardiovascular considerations:

  • These chronically hypertensive patients may require higher MAP to perfus their organs
  • They are prone to pericardial effusions
  • The myocardium may be hypertrophied
  • Atheromatous disease is amplified; coronary artery disease will likely be present

D) Pharmacokinetics are affected:

  • Renally cleared substances will persist until the next dialysis session
  • Renally cleared metabolites will also have a persisting effect
  • Volume of distribution is increased

Neurological function can be impaired by high urea

E) Electrolyte and acid-base balance will be disturbed:

  • High potassium
  • High phosphate
  • Accumulation of non-volatile acids (sulfate, urate, etc)

F) Fluid balance will be disturbed:

  • Inability to produce urine makes the patient more likely to develop fluid overload
  • Dialysis disequilibrium syndrome may develop

G) Nutrition is affected:

  • Low-protein diets are usually required to decrease the rate of urea production.
  • Albumin may be low (eg. with nephrotic syndrome) which decreases its positive antioxidant and scavenging effect.

H) There may be anaemia due to decreased EPO synthesis.

I) There may be immune dysfunction and increased risk of infection.

References

References

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.

 

Szamosfalvi, Balazs, and Jerry Yee. "Considerations in the critically ill ESRD patient." Advances in chronic kidney disease 20.1 (2013): 102-109.