Polycythemia

[militarymd]

Is there a hct where any of you would not put someone to sleep for a low risk surgery....

Is there a hct below which or about which you would limit anesthesia time to a certain length of anesthesia time?

Is there any evidence or data out there to support the recommendations?

I know about the PVSG recommendations, but they do not apply to anesthesia...just out patient management.

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[supahfresh]

and if they are Jehovah's witness, how does that change your management?

 

[jetproppilot]

Is there a hct where any of you would not put someone to sleep for a low risk surgery....

Is there a hct below which or about which you would limit anesthesia time to a certain length of anesthesia time?

Is there any evidence or data out there to support the recommendations?

I know about the PVSG recommendations, but they do not apply to anesthesia...just out patient management.

I'm gonna shoot from the hip Mil, since I'm not aware of any overwhelming current literature.

But its a complex question.

Concerning a high hct, I've routinely put people to sleep with hct in the fifties...mostly smokers. Dont think I've seen anything above 55-56.

I dont know the answer for risk with anesthesia and surgery for someone with a hct higher than that. It'd have to be higher than 59-60 to cancel an elective case. I have no evidence for those numbers.

Low hct presenting for surgery is, as you know, much more common.

Not uncommon to see hcts in the low twenties/high teens for women presenting for intervention for dysfunctional uterine bleeding. Young healthy ones rarely require blood. Theres not a hct low enough within reason that I wont put a twenty something girl to sleep for concerning this situation. Their cardiovascular system is very compensative and can sustain supra-normal cardiac outputs until the hct comes up.

I've done several ectopics on young healthy girls with hcts in the 8-10 range....of course they all got blood, most times the first unit running while youre going to sleep, so maybe their crit was up to 10-11-12...but point is..young people tolerate very low crits pretty well.

Look at the other side of the spectrum...

I've done many, many bring back hearts in ten years with hcts in the 14-16 range....obviously these are critically ill people who undergo a general (albeit very tailored) anesthetic, and most do not die from the low hct, and certainly most suffer minimal sequalae from the general anesthetic.

The only literature I'm aware of thats pretty relevant is the emerging literature showing that patients benefit from higher hcts while on pump. Ten years ago crits in the high teens (mostly from hemodilution...from pump prime, fluids during case)... on patients who present with a lower than normal hct to the OR.....(yes, apparently the cardiologists in the cath lab lose a fair amount of blood routinely during diagnostic/interventional cath lab cases)...were routinely tolerated during/after pump run.

Now I think the trend is to keep hct in mid-high twenties, at least.

Now theres alotta mostly non-literature backed up B.S. that doesnt even answer the question.

But its based on my experience and comfort levels at this point in my career.

I'll post more if I think of anything relevant.

 

[militarymd]

I'm not worried about the low hct.....I'm wondering how high is oK..

 

[jetproppilot]

I'm gonna shoot from the hip Mil, since I'm not aware of any overwhelming current literature.

But its a complex question.

Concerning a high hct, I've routinely put people to sleep with hct in the fifties...mostly smokers. Dont think I've seen anything above 55-56.

I dont know the answer for risk with anesthesia and surgery for someone with a hct higher than that. It'd have to be higher than 59-60 to cancel an elective case. I have no evidence for those numbers.

Low hct presenting for surgery is, as you know, much more common.

Not uncommon to see hcts in the low twenties/high teens for women presenting for intervention for dysfunctional uterine bleeding. Young healthy ones rarely require blood. Theres not a hct low enough within reason that I wont put a twenty something girl to sleep for concerning this situation. Their cardiovascular system is very compensative and can sustain supra-normal cardiac outputs until the hct comes up.

I've done several ectopics on young healthy girls with hcts in the 8-10 range....of course they all got blood, most times the first unit running while youre going to sleep, so maybe their crit was up to 10-11-12...but point is..young people tolerate very low crits pretty well.

Look at the other side of the spectrum...

I've done many, many bring back hearts in ten years with hcts in the 14-16 range....obviously these are critically ill people who undergo a general (albeit very tailored) anesthetic, and most do not die from the low hct, and certainly most suffer minimal sequalae from the general anesthetic.

The only literature I'm aware of thats pretty relevant is the emerging literature showing that patients benefit from higher hcts while on pump. Ten years ago crits in the high teens (mostly from hemodilution...from pump prime, fluids during case)... on patients who present with a lower than normal hct to the OR.....(yes, apparently the cardiologists in the cath lab lose a fair amount of blood routinely during diagnostic/interventional cath lab cases)...were routinely tolerated during/after pump run.

Now I think the trend is to keep hct in mid-high twenties, at least.

Now theres alotta mostly non-literature backed up B.S. that doesnt even answer the question.

But its based on my experience and comfort levels at this point in my career.

I'll post more if I think of anything relevant.

Seems like I always click the reply button the millisecond something else hits my brain....

concerning TIME of anesthesia, I think for the most part clinical decisions are independent of anesthesia time.

Very rare that you think "uhhh, dude you better hurry up because this guy may die", since most of the time you think that, surgeon dude is working on the very problem that is trying to kill the patient.....

....with the exception of unanticipated cardiac arrhythmias......had a case a cuppla months ago...sudden onset supra-V tach on a basilic vein transfer that was prepped and draped but hadnt started....woke the dude up. Cancelumundo.

Low crits, high crits, high coags, low Ca++, low K+, high K+, low glucose, high glucose, etc etc ....can be fixed during the operation.

OK, heres how I sum up the plethora of thoughts running through my brain by Mil's excellent question.

Patient REALLY screwed up for emergency case: of course proceed.

Patient REALLY screwed up for elective case, cancel.

Patient mild-moderately screwed up for elective case: we can address the problems, if necessary, intraoperatively.

hmmmmmmmmmmm...

I think I could publish the above and call it something eloquent like...

PREOPERATIVE DECISION MAKING AND APPROPRIATE STRATIFICATION OF THE OPERATIVE POPULATION

 

[jetproppilot]

I'm not worried about the low hct.....I'm wondering how high is oK..

i dont know.

 

[jetproppilot]

Patient REALLY screwed up for emergency case: of course proceed.

Patient REALLY screwed up for elective case, cancel.

Patient mild-moderately screwed up for elective case: we can address the problems, if necessary, intraoperatively.

hmmmmmmmmmmm...

I think I could publish the above and call it something eloquent like...

PREOPERATIVE DECISION MAKING AND APPROPRIATE STRATIFICATION OF THE OPERATIVE POPULATION

HAHAHHAHAHAHAHAHAHAHHAHAHAHAHAH

geez I crack myself up

but then again, that stratification is accurate.

 

[Cap'nOblivious]

So what would the concern be for proceeding with surgery with an elevated crit? Coagulopathy? Microemboli? It seems like a little "bloodletting" would actually be therapeutic in this case, particularly if the intravascular volume is higher than normal.... Otherwise, wouldn't hemodilution (as tolerated) be an easy fix?

 

[militarymd]

thrombosis...clotting to death..


There are time dependent factors ....pump run time...longer more like to have problems..

Just the first thing that pop into my mind.....I'm sure there are others..

for polycythemia...I don't have data...but it would seem the longer you are under, the more likely you will have thrombotic complications....that's why I'm asking.


aortic clamp time and renal injury...

length of back surgery and vision loss....

 

[UTSouthwestern]

So what would the concern be for proceeding with surgery with an elevated crit? Coagulopathy? Microemboli? It seems like a little "bloodletting" would actually be therapeutic in this case, particularly if the intravascular volume is higher than normal.... Otherwise, wouldn't hemodilution (as tolerated) be an easy fix?

The high hematocrit itself is not necessarily what should concern you. It is the mechanism by which the high hematocrit was generated. Chronic hypoxia? Renovascular disease and decreased renal perfusion causing inappropriate EPO production? Exogenous EPO administration? Renal or other tumors causing direct or indirect stimulation for the production of EPO or RBC's?

Not knowing what the underlying pathology could be as well as the consequences of polycythemia and proceeding with a case is what will get you into trouble the most. For the most part you don't need to cancel a case. However, you should be aware that the polycythemia and concurrent increased blood viscosity will impair microcirculation in the acute phase and stimulate sympathetic tone in the chronic phase as the body uses vasoconstriction and increases in inotropy and chronotropy to increase the velocity of RBC circulation and oxygen delivery.

What could happen if your patient has a high basal sympathetic tone that your general anesthetic abates? What could happen if you drop the patient's pressure below a threshold pressure through which most of the organs and distal tissues are receiving perfusion? Can this drop result in an occult insult to the kidneys? Will underlying cardiac strain and subsequent decreased cardiac reserve be greatly impacted by anesthetic mediated hemodynamic fluctuations?

All of the questions need to be considered in context with the general health of the patient as well as other risk factors that may contribute to cardiovascular outcomes.

Is there a hard and fast number beyond which a case should be cancelled? I have never read of such a number. From my limited experience with COPD mediated polycythemia, maintaining adequate oxygen tension, keeping heart rates in the normal range, and keeping the patient normocarbic to slightly hypocarbic keeps the physiologic milieu of the patient stable enough to allow a procedure to continue while avoiding exacerbation of underlying CV disease.

Of course with unpredictable hormone/protein secreting tumors, you may be SOL regardless of how meticulous and gentle you are with the patient.

 

[UTSouthwestern]

for polycythemia...I don't have data...but it would seem the longer you are under, the more likely you will have thrombotic complications....that's why I'm asking.

This is an accurate statement and is worst in those patients who become hypovolemic 2/2 blood loss with compensatory vasoconstriction. Keeping the patients normovolemic and avoiding hypoxia should minimize that risk.

 

[VentdependenT]

Just got finished reading the old mandatory miller chapter o the month: cardiac. So's I found the following:

There is a little graph depicting HCT vs Systemic transport of oxygen:
- maximal delivery at hcg 35-45
hct 60 - delivery 95%
hct 70 - delivery 90%
hct 80 - delivery 85%
hct 90 - delivery 80%

If the pt gets cold though that high hct becomes more viscious and the delivery will get worse. How worse, dunno. Someone probably does though.

You could hemodilute em down if their heart and vasculature can handle the fluid and let em bleed fer a while before administering products. The big question however is why their hct is so damn high.

Thats all I gots.