S/P dialysis, No K level?

[DrDre']

THinking about Noyac and Jet's posts, practicing safe anesthesia without being obstructionalist...

Several times I have had staff delay starts for HD pts s/p dialysis without a current K level. (Getting a quick K is no prob but...)

If someone was dialyzed within 24 hours and hasnt been eating at all, would you delay an elective case for a K level, draw it asap in the OR...

I absolutely understand the concerns. Realistically, if 95% of ESRD pts get dialyzed q 48 hours then their K is likely "safe" for 24 hours?!

Thoughts...

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[drmwvr]

THinking about Noyac and Jet's posts, practicing safe anesthesia without being obstructionalist...

Several times I have had staff delay starts for HD pts s/p dialysis without a current K level. (Getting a quick K is no prob but...)

If someone was dialyzed within 24 hours and hasnt been eating at all, would you delay an elective case for a K level, draw it asap in the OR...

I absolutely understand the concerns. Realistically, if 95% of ESRD pts get dialyzed q 48 hours then their K is likely "safe" for 24 hours?!

Thoughts...

Well, just for arguments sake, and leaving aside the quick turnover of a simple serum potassium (hard to call that a delay when it can be back before you place monitors) there aren't many factors that could alter K+ in the immed. post HD pt, but one that can is fasting. Most of those 95% aren't coming to the OR, so they don't count. Based on that alone, I vote "delay".

 

[Consigliere]

Maybe in an academic environment getting a K+ takes a few minutes. I can tell you that at least where I work it is a MINIMUM 1 hour ordeal. I don't delay cases for what are usually normal K+'s.

Short answer - I never get 'em

 

[Planktonmd]

For those who actually insist on getting a potassium level before surgery on a patient who had dialysis in the past 24 hours ask yourself this question:
How many times have you actually gotton a post-dialysis potassium level that was high enough that you had to delay the surgery???
I say it would be extremely rare.
So, if a patient had dialysis 24 hours ago and there is no EKG signs of severe hyperkalemia, go to surgery.

 

[pushthesux]

So, if a patient had dialysis 24 hours ago and there is no EKG signs of severe hyperkalemia, go to surgery.

So that means you have to get an EKG?

 

[Planktonmd]

So that means you have to get an EKG?

Not really, you do connect patients to a monitor don't you??
If you see big T waves or strange looking QRS that did not exist before then get a K level.

 

[drmwvr]

For those who actually insist on getting a potassium level before surgery on a patient who had dialysis in the past 24 hours ask yourself this question:
How many times have you actually gotton a post-dialysis potassium level that was high enough that you had to delay the surgery???
I say it would be extremely rare.
So, if a patient had dialysis 24 hours ago and there is no EKG signs of severe hyperkalemia, go to surgery.

Patient selection for going without has to come into play. Arterial tourniquet, ace inhibitors, throw in a long fast. What's the downside there? The EKG might not change until around 6 or better. What is really rare is not being surprised at an elevated serum K for an elective surgery. I always expect the lytes to be normal, but that isn't why I send/look at them, and not sending them because they are most usually normal isn't something I could defend. An index of suspicion, to me, means not just knowing that the K is probably ok. It is needing to know what the K is.

 

[cchoukal]

We have an attending that insists the K may be at its highest for the first few hours after HD. This is based on her understanding that after the K is removed from the plasma by the dialysate, it will then requilibrate from the intracellular stores back into plasma. Of course, by definition, re"equilibrate" shouldn't RAISE the K, but whatever. We frequently do kidney transplants immediately after dialysis and the bloodgas never shows high K (although I respect drmvwr's point about "knowing"). All that said, if they dialyzed the day before and it was a normal run, I don't frequently look at a K.

I have some attgs who look at the rhythm strip on the monitor in pre-op to decide if we need a K, but I don't know how sensitive/specific those are for the specific EKG changes associated with hyper-K.

 

[Planktonmd]

Patient selection for going without has to come into play. Arterial tourniquet, ace inhibitors, throw in a long fast. What's the downside there? The EKG might not change until around 6 or better. What is really rare is not being surprised at an elevated serum K for an elective surgery. I always expect the lytes to be normal, but that isn't why I send/look at them, and not sending them because they are most usually normal isn't something I could defend. An index of suspicion, to me, means not just knowing that the K is probably ok. It is needing to know what the K is.

No one said it's wrong to check a potassium level but the question is: In the situation where the patient had dialysis 24 hours ago and the potassium level was not checked do you want it bad enough that you are willing to delay a surgery to wait for it?
The other question is if you insist on waiting can you tell us what potassium number will make you decide to not proceed?
Keep in mind that people with CRF usually tolerate much higher numbers than the average person.
Let's say the potassium is 6 but the EKG is normal, would you cancel ?
How about 6.5?
How about a potassium of 5.9 and an EKG that shows giant T waves?
Is there any rules?
Do these rules have any scientific evidence to support them?

 

[drmwvr]

No one said it's wrong to check a potassium level but the question is: In the situation where the patient had dialysis 24 hours ago and the potassium level was not checked do you want it bad enough that you are willing to delay a surgery to wait for it?
The other question is if you insist on waiting can you tell us what potassium number will make you decide to not proceed?
Keep in mind that people with CRF usually tolerate much higher numbers than the average person.
Let's say the potassium is 6 but the EKG is normal, would you cancel ?
How about 6.5?
How about a potassium of 5.9 and an EKG that shows giant T waves?
Is there any rules?
Do these rules have any scientific evidence to support them?

The rules are definitely self imposed and are without a doubt, fluid. 6 with a normal ekg? Might take a fem-pop to the OR as well as a forehead bcca (I confess, I might not even send the K for the bcca) I'd think twice about bringing a foot arthrodesis, though. Depends on the case and the patient. The 6.5 and the 5.9, assuming no artifact, no. You're right, we did drift of the original question, though. My final answer? It depends.😀