elective case

[urge]

Let's say you are doing an elective abdominal case on a old guy >75y/o with documented CRI who is found to have worsened creatinine on preop testing. Would you do it? Is surgery going to affect CRI? Delay the case for more testing?

Any thoughts?

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[TIVA]

75 y.o, CRI, recent worsening of creatinine, elective abdominal procedure -- I'd delay the case and have the patient see his PCP.

The point isn't to get needless tests or subject the patient to a lot of inconvenience for little gain, but to optimize the patient about to undergo trauma and insult.

Perhaps all the PCP needs to do is tweak his diuretics or antihypertensives. Or at the very minimum, get an echo to evaluate for changes in cardiac function.

Chances are high that surgery will further exacerbate his renal function and if he isn't properly optimized or evaluated, he'll go home with a dialysis catheter and a scar, and not just a scar.

 

[zippy2u]

"Abdominal surgery" is rather vague to say the least. Say it's your garden variety sigmoid resection. Find a fast surgeon that doesn't lose blood and get the case done. Who has time for all that renal US, urine Na, creatinine clearance BS. GETA the man, throw him over in the ICU and call an ICU guru like Militaryman to work some magic. Regards, ---Zippy

 

[militarymd]

Let's say you are doing an elective abdominal case on a old guy >75y/o with documented CRI who is found to have worsened creatinine on preop testing. Would you do it? Is surgery going to affect CRI? Delay the case for more testing?

Any thoughts?

Unstable renal function is definitely a reason delay a surgery where renal blood flow is going to be compromised.

 

[coprolalia]

-Hold the ACE.
-Light on the fluids.
-50-100 meq NaHCO₃ intraop
-25-50g mannitol intraop
-40-80mg furosemide intraop
-Watch the Foley like Hillary Clinton watching the exit polls.

Done.

-copro

 

[Planktonmd]

When we are talking about worsening creatinine is that:
1- Creatinine 5 years ago was 1.6 and now 1.8
or
2- Creatinine 2 months ago 1.6 and now 7 ?

 

[cchoukal]

Actually, there was an article in the december Anesthesiology on predicting post-op renal failure in a general surgery population. They identified several pre-op risk factors (age over 59, obesity, PVD, COPD, emergency surgery) and intra-op risk factors (vasopressor use, diuretic use) which predicted HIGHER likelihood of post op ARF...

So by Copro's plan, he'd have at least two hits: age and diuretic use intra-op...

I tried posting the link, but it appears proprietary... here's the text of the abstract at least:

Background: The authors investigated the incidence and
risk factors for postoperative acute renal failure after major
noncardiac surgery among patients with previously normal
renal function.
Methods: Adult patients undergoing major noncardiac surgery
with a preoperative calculated creatinine clearance of 80
ml/min or greater were included in a prospective, observational
study at a single tertiary care university hospital. Patients
were followed for the development of acute renal failure
(defined as a calculated creatinine clearance of 50 ml/min
or less) within the first 7 postoperative days. Patient preoperative
characteristics and intraoperative anesthetic management
were evaluated for associations with acute renal failure.
Thirty-day, 60-day, and 1-yr all-cause mortality was also evaluated.
Results: A total of 65,043 cases between 2003 and 2006 were
reviewed. Of these, 15,102 patients met the inclusion criteria;
121 patients developed acute renal failure (0.8%), and 14 required
renal replacement therapy (0.1%). Seven independent
preoperative predictors were identified (P < 0.05): age, emergent
surgery, liver disease, body mass index, high-risk surgery,
peripheral vascular occlusive disease, and chronic obstructive
pulmonary disease necessitating chronic bronchodilator therapy.
Several intraoperative management variables were independent
predictors of acute renal failure: total vasopressor dose
administered, use of a vasopressor infusion, and diuretic administration.
Acute renal failure was associated with increased
30-day, 60-day, and 1-yr all-cause mortality.
Conclusions: Several preoperative predictors previously reported
to be associated with acute renal failure after cardiac
surgery were also found to be associated with acute renal failure
after noncardiac surgery. The use of vasopressor and diuretics
is also associated with acute renal failure.

 

[coprolalia]

So by Copro's plan, he'd have at least two hits: age and diuretic use intra-op...

Baahh. He's already got CRI. I'm just protecting what's left. The study you post is like trying to compare apples to oranges.

-copro

 

[cchoukal]

yes, the sample had normal renal function pre-op.

 

[militarymd]

-Hold the ACE.
-Light on the fluids.
-50-100 meq NaHCO₃ intraop
-25-50g mannitol intraop
-40-80mg furosemide intraop
-Watch the Foley like Hillary Clinton watching the exit polls.

Done.

-copro

couple of points here:

volume of intraop urine output has been shown to not correlate with post op renal function in Aortic surgery ....about as HIGH a risk of worsening renal function.

diuretic therapy.....theorized a lot , but I have yet to see convincing data.

 

[Noyac]

Well this whole case is speculation b/c we don't know the amount of change in CR and we don't know the type of abdominal case. If this is a bowel resection vs a ventral hernia repair, small bump in CR vs 20% increase etc.

 

[SexPanther]

couple of points here:

volume of intraop urine output has been shown to not correlate with post op renal function in Aortic surgery ....about as HIGH a risk of worsening renal function.

diuretic therapy.....theorized a lot , but I have yet to see convincing data.

Another ? I had reading these posts was what was the insult that led to his AKI in the setting of CRI. If he'd been vomiting for several days prior or had other signs of hypovolemia, it seems like hitting him with lasix and mannitol intra-op could be counterproductive. In that scenario, the pt. would likely benefit from fluid administration with careful monitoring to ensure that he didn't develop severe volume overload. Or maybe he had bad BPH and hadn't been able to urinate for several days; a foley would go a long way. I'm trying to say that the clinical context of his worsening renal fxn makes a big difference in the management. Am I way off base here?

 

[coprolalia]

The OP said CRI.

To get to the point of CRI, you have basically lost 90% of your renal function. Kidneys tip over easily at this point, and small changes in baseline status will create significant changes in pre-op lab testing.

Adopt a renal protective strategy early. Your patient will benefit. We're not talking about a healthy kidney that takes a hit during a procedure because of inadequate perfusion (etc.) during the case.

-copro

 

[urge]

Pt was taken off lasix. Seemed like dehydration. Repeat labs 2 days later showed improved creatinine. We did the case w/o problems.

I was just wondering what would be the best approach if the repeat labs showed no change in crt. Would it be worthwhile to wait for something that you could not fix? Would a short anesthetic for something like a hernia tip the kidneys off? Should the pt live with a hernia because surgery/anesthesia might make it worse? I actually wanted to do the case regardless of crt level but everybody around me was so concerned about it that I felt bad proceding.

 

[militarymd]

As long as GFR is stable and unchanging....low risk surgery should not be a problem.

I was under the impression that there was a CHANGE in the GFR and no one knows what caused the change.

 

[Planktonmd]

Pt was taken off lasix. Seemed like dehydration. Repeat labs 2 days later showed improved creatinine. We did the case w/o problems.

I was just wondering what would be the best approach if the repeat labs showed no change in crt. Would it be worthwhile to wait for something that you could not fix? Would a short anesthetic for something like a hernia tip the kidneys off? Should the pt live with a hernia because surgery/anesthesia might make it worse? I actually wanted to do the case regardless of crt level but everybody around me was so concerned about it that I felt bad proceding.

If a patient is demonstrating an unexpected and worrisome increase in creatinine that can not be explained by the normal progress of his underlying disease, then I think elective surgery should be delayed until we address any factor that can be causing that increase and can be corrected:
Better BP control, better DM control, better diet, remove harmful medications if any, treat any infection.....
That benign elective surgery might be all that is needed to put the patient in ESRD.
One more point: Intra-operative renal protective strategies, no matter how enthusiastic one might feel about them, remain hypothetical and contain a great deal of wishful thinking.

 

[seinfeld]

-Hold the ACE.
-Light on the fluids.
-50-100 meq NaHCO₃ intraop
-25-50g mannitol intraop
-40-80mg furosemide intraop
-Watch the Foley like Hillary Clinton watching the exit polls.

Done.

-copro

A little confused. Perhaps your reply is in reference to someone who by the RIFLE criteria is already headed toward Failure, Loss and ESRD.

It sounds like this patient just has ARI. In that case diuresis is the last thing to do, unless you are converting oligouria into polyuria for volume management reasons(although not EBM). Otherwise diuresis is like giving a patient with an acute MI some epi to improve Cardiac outpt when all other parameters like BP and HR are nl. As mil said the intraop urine outpt may make us feel better but it actually has no correlation to post op renal function. Instead of watching the foley, its probably better ensure adequate hydration and Normal BP for the patient. The Hco3 i assume would be only if he/she were extremely acidotic?

 

[coprolalia]

It sounds like this patient just has ARI.

This was the exact quote from the OP:

... with documented CRI who is found to have worsened creatinine on preop testing.

He may be dry. I don't know. He may be on an ACE. I don't know. He may be approaching kidney failure. I don't know.

A >75-year-old is not going to turn over a lot of creatinine to begin with. So, you need to be suspicious when the creatinine is high in this population. It would be nice to see what the BUN:creat ratio was, as this would point to the fact that he is dehydrated. But, we don't have that. On the face of it, I assumed that he is getting worsening renal insufficiency.

Also, what kind of belly case is this? Does he have a big aortic aneurysm that is impeding blood flow to the kidneys?

Stopping the ACE (if he's on one) is the first choice.

Light on the fluids is the second, if he's in renal failure and not dry. If he's not pumping out the fluid, then there's no point putting more in and possibly putting him into failure.

Bicarb will be a part of the renal protective strategy by alkalinizing the urine and protecting him further from that protein load going through his kidneys (as well as offsetting the effects of mannitol). Same for the diuretics, mannitol and lasix, which will both increase GFR and also increase the amount of solute going into the urine. You want to see him pee during the case. Peeing is better than not peeing in someone with kidney failure (whatever degree), even though some might argue that you're only making yourself feel better.

That's my rationale right or wrong, given the fact that the case is elective you could equally make an argument to see more data. But, we don't have that information. Other points made on this thread (etiology of the abdominal case, etc.) are valid too. Point is, if you don't need to rush to the OR, don't. We all want more information. However, based on the info we have, there's no indication that whatever you do is going to substantially impact long-term outcome in someone who's over >75 and is undergoing abdominal surgery. And, I seriously doubt that the strategy I advocate is going to push him into full-blown renal failure.

-copro

 

[Planktonmd]

This was the exact quote from the OP:

He may be dry. I don't know. He may be on an ACE. I don't know. He may be approaching kidney failure. I don't know.

A >75-year-old is not going to turn over a lot of creatinine to begin with. So, you need to be suspicious when the creatinine is high in this population. It would be nice to see what the BUN:creat ratio was, as this would point to the fact that he is dehydrated. But, we don't have that. On the face of it, I assumed that he is getting worsening renal insufficiency.

Also, what kind of belly case is this? Does he have a big aortic aneurysm that is impeding blood flow to the kidneys?

Stopping the ACE (if he's on one) is the first choice.

Light on the fluids is the second, if he's in renal failure and not dry. If he's not pumping out the fluid, then there's no point putting more in and possibly putting him into failure.

Bicarb will be a part of the renal protective strategy by alkalinizing the urine and protecting him further from that protein load going through his kidneys (as well as offsetting the effects of mannitol). Same for the diuretics, mannitol and lasix, which will both increase GFR and also increase the amount of solute going into the urine. You want to see him pee during the case. Peeing is better than not peeing in someone with kidney failure (whatever degree), even though some might argue that you're only making yourself feel better.

-copro

So, you want to restrict fluids but at the same time you want to give a volume load in the form of Bicarb and Mannitol ?
Are you sure that loop diuretics increase GFR?

 

[coprolalia]

So, you want to restrict fluids but at the same time you want to give a volume load in the form of Bicarb and Mannitol ?
Are you sure that loop diuretics increase GFR?

150 mL of fluid to give 25g of mannitol and 50meq of bicarb. Not exactly a fluid bolus.

Mannitol increase GFR. Lasix diureses. You're going to dry him out more, clearly. But, I'm assuming that he's in possibly acute on chronic renal failure and not clearing fluids.

If his BUN is elevated and his creatinine is bumped, this changes everything. Mental masturbation here. No doubt.

-copro

 

[Planktonmd]

150 mL of fluid to give 25g of mannitol and 50meq of bicarb. Not exactly a fluid bolus.

Mannitol increase GFR. Lasix diureses. You're going to dry him out more, clearly. But, I'm assuming that he's in possibly acute on chronic renal failure and not clearing fluids.

If his BUN is elevated and his creatinine is bumped, this changes everything. Mental masturbation here. No doubt.

-copro

1- As you know, when you give an osmotic diuretic (Mannitol) you are not only giving the volume of the diuretic itself but also causing a significant increase in intravascular volume by shifting fluids toward the intravascular compartment and hoping the kidney will be able to eliminate that extra volume or you won't really be helping the patient.
2- Sodium bicarb is not only volume but also a major sodium load.
3- Why is an IV loop diuretic good for protecting the kidney regardless of the hydration status?

 

[coprolalia]

1- As you know, when you give an osmotic diuretic (Mannitol) you are not only giving the volume of the diuretic itself but also causing a significant increase in intravascular volume by shifting fluids toward the intravascular compartment and hoping the kidney will be able to eliminate that extra volume or you won't really be helping the patient.

This is a transient effect. You are increasing GFR by the mannitol, and you will only get a temporary bump in BP (for example) before you dump the fluid. The net-effect is overall body water loss provided the kidney dumps urine (hence the furosemide). This patient has CRI, not ESRD. So, unless he's producing no urine (no indication of this) it will work.

2- Sodium bicarb is not only volume but also a major sodium load.

Agreed. But, I'm only giving 50meq of bicarb. And, unless his Na+ is already >145, it's not going to hurt anything. Plus, we're assuming (again) that he is in CRI and probably slightly fluid overloaded. Probably will have a somewhat low-normal to low serum Na+ to begin with. Plus, you're giving mannitol which can tend to cause an acidosis.

3- Why is an IV loop diuretic good for protecting the kidney regardless of the hydration status?

Water's gotta go somewhere. Peeing is better than not peeing. For the reasons you elucidate, you want to make sure that kidney is dumping. So, not really "protecting" the kidney, but protecting overal renal output (if you will) by making sure your other actions maintain the net effect of moving fluid into the bladder. I did give him mannitol after all, right?

I'm essentially treating this patient like a supra-renal aortic crossclamp.

-copro

 

[Planktonmd]

This is a transient effect. You are increasing GFR by the mannitol, and you will only get a temporary bump in BP (for example) before you dump the fluid. The net-effect is overall body water loss provided the kidney dumps urine (hence the furosemide). This patient has CRI, not ESRD. So, unless he's producing no urine (no indication of this) it will work.

The mannitol will remain longer and cause a longer intra vascular expansion in chronic renal failure and that might be all you need to put this patient in CHF especially if you add a sodium load to it. This also goes against your strategy of "not too much fluids".

Water's gotta go somewhere. Peeing is better than not peeing. For the reasons you elucidate, you want to make sure that kidney is dumping. So, not really "protecting" the kidney, but protecting overal renal output (if you will) by making sure your other actions maintain the net effect of moving fluid into the bladder. I did give him mannitol after all, right?

I'm essentially treating this patient like a supra-renal aortic crossclamp.

-copro

There is a difference between protecting a normal kidney from ischemia and trying to push a diseased kidney to work harder in order to increase urine output.
Diuretics are toxic to the kidney and they might actually cause a decrease in GFR (a known fact for thiazides and debated for loop diuretics).
I am just trying to say that all these interventions you mentioned are of questionable value in protecting the kidney and the best thing you can do for patients with chronic kidney disease is optimize their long term treatment before you expose them to elective surgery.