Question 29

A 22-year-old patient is admitted with an acute traumatic brain injury with raised intracranial pressure. They also have a severe acute kidney injury requiring renal replacement therapy (RRT). Outline the potential issues of providing RRT, including your management of the issues

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College answer

Not available.


This question is a reworded version of Question 21 from the first paper of 2018, which means readers can go there to see what the official college answer would likely have been.

Recommendations for Renal replacement Therapy in Patients with traumatic Brain Injury
Domain Recommendations Rationale
Access Avoid internal jugular lines Promote venous drainage from the brain
Modality Prefer CRRT Produces a more gradual solute clearance; 
less likely to produce cerebral oedema
  Low efficiency IHD/SLED
Frequency Daily, if not continuous Daily treatments decrease the fluctuations of urea 
Blood flow Start low, increase slowly Minimise haemodynamic effects
Dialysate flow Start low, increase slowly Minimise solute clearance
Dose Under-dialyse (by half) Minimise solute clearance per unit time
Solute clearance Pre-dilution haemofiltration Minimise urea clearance: decrease the resulting urea gradient between brain parenchyma and blood, minimising cerebral oedema 
Filtration Low volume fluid removal Minimise dialysis-associated hypotension to prevent cerebral hypoperfusion
Anticoagulation Regional, or none Prevent cerebral haemorrhage extension due to anticoagulation. Minimal anticoagulation is recommended for 2 weeks following TBI.
Dialysate Add sodium Minimise the hyponatremia which develops due to exposure to hyponatremic dialysate (to keep sodium around 145-150 mmol/L)
Add urea Minimise urea clearance
Minimise bicarbonate Prevent intracellular acidosis (may be hypthetical)
Fluid warmer Temperature matching Maintain therapeutic hypothermia if this is being used for ICP control


Davenport, Andrew. "Renal replacement therapy in the patient with acute brain injury." American journal of kidney diseases37.3 (2001): 457-466.

Davenport, Andrew. "Renal replacement therapy for the patient with acute traumatic brain injury and severe acute kidney injury." Acute Kidney Injury. Vol. 156. Karger Publishers, 2007. 333-339.

Davenport, Andrew. "Practical guidance for dialyzing a hemodialysis patient following acute brain injury." Hemodialysis International 12.3 (2008): 307-312.

Yeh, Shih-Hao, Chen-Yu Wang, and Chien-Min Lin. "Preventing intracranial pressure fluctuation in severe traumatic brain injury during hemodialysis." Journal of Medical Sciences 36.4 (2016): 152.