Tuesday, 10 June 2014

Dialysis

Dialysis is surprisingly difficult to find information about. In the emergency department, I think we're only interested in:
 - how do we not look stupid when a renal patient comes in
 - which patients do we need to arrange urgent dialysis for
 - what do we do differently with a sick patient on dialysis

Overview

There are two main types of "routine" dialysis. In ICU it is different, and their dialysis is normally continuous, and there are many different types.


- Haemodialysis
Fine fibre tubes mimic the body's glomeruli, and filter the blood. Semi permiable. Waste products carried away. You need hydrostatic pressure to be able to increase.

- Peritoneal dialysis
Dialysis fluid introduced into the adbdominal cavity. Waste transfers through the peritoneal membrane into the fluid. Abdomen then drained. Could be continuous ambulatory peritoneal dialysis - which doesn't need a machine, or continuous cycler-assisted peritoneal dialysis.

Urgent Dialysis
I think the most common cause of urgent dialysis from the ED is hyperkalaemia, and potentially drug overdose. Dialysis might also be indicated for pulmonary oedema.

Not all drugs are dialysed out successfully.



Sick Dialysis Patient
- Speak to their renal unit
- Check electrolytes
- Fluid overload normally needs dialysis, as diuretics need functioning kidneys
- Infection is a leading cause of death - always send cultures. Pyrexia is often related to gram positive sepsis.
- Anticoagulation - renal failure often leads to a bleeding tendency. Ask which anticoagulants have been used.

- Dialysis related hypotension is the most frequent symptomatic complication. It is caused by reflex withdrawal of sympathetic tone resulting from reduced left ventricular filling. This normally happens because the patient's fluid balance is suboptimal.
- Cramps are common and might be due to volume depletion and tissue hypoxia. Hypertonic fluid, like 50mls of 50% dextrose often raises plasma osmolality and helps.

- The most serious acute events during dialysis include air embolism, line disconnection leading to haemorrhage, acute haemolysis or toxicity related to line kinking or dialysis contamination, and acute allergic reactions to dialysers or sterilants (ethylene oxide).

Lines
Don't touch the fistula. When cannulating use veins as distal as possible, to try and preserve the bigger access.
Bleeding fistula are often caused by infection. They need compression, possibly topical tranexamic acid, and urgent vascular referral.




References
http://ccforum.com/content/pdf/cc10280.pdf
http://lifeinthefastlane.com/tag/dialysis/
https://www.emrap.org/episode/2013/april/thehypotensive
http://www.emlitofnote.com/2011/12/risks-of-missing-dialysis.html
http://academiclifeinem.com/mythbuster-urgent-dialysis-following-iv-contrast/
http://www.kidneydialysis.org.uk/hemodialysis.htm
http://www.kidneyatlas.org/book5/adk5-01.ccc.QXD.pdf
http://www.edrep.org/pages/textbook/haemodialysis.php
http://openmed.co.uk/curriculum/renal/
http://www.frca.co.uk/article.aspx?articleid=100367
http://www.frca.co.uk/Documents/194%20Renal%20replacement%20therapy%20in%20critical%20care.pdf
http://www.learnicu.org/Presentations/RRT%20in%20ICU.ppt
http://www.ccmtutorials.com/renal/rrt/index.htm

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