Colloids versus Crystalloids AGAIN!

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There is an excellent review article in the October 2008 "Anesthesiology" that everyone should read. It provides a solid scientific framework, including changes in the endothelium with the administration of crystalloid, that helped make a lot more sense to me about my clinical observations following massive crystalloid resuscitation.

Check it out. Great article.

A Rational Approach to Perioperative Fluid Management

-copro
 
ARGH - not again!!!

First things first - I don't do veterinary anaesthesia, so I wouldn't mind seeing some similar work done in humans to see if any aspects of this can be replicated (obviously some things are easier to do in pigs....but you get the idea).

Secondly the article opens talking about hypovolaemia "contribut[ing] to intestinal hypoperfusion and subsequent postoperative complications" but this study is unable to address the question of clinically significant postoperative complications. Does pentastarch change these or just the numbers?

At the moment this is certainly not going to alter my management of trauma (NS for resus and if they need colloid they get blood), but it might make me think about the next non emergent laparotomy I do (before sticking with my original crystalloid plan..esp as we don't have pentastarch at my hospital, just gelofusine).

PS: thanks for that article copro - I think I've seen it before, but I think I'll reread it at work tonight.
 
NEJM Jan 08: "The trial was stopped for safety reasons... HES therapy was associated with higher rates of renal failure and RRT than Ringer's lactate."

Convincing benefit of colloid use has still to be brought forth.
 
Licoricestick said:
First things first - I don't do veterinary anaesthesia, so I wouldn't mind seeing some similar work done in humans to see if any aspects of this can be replicated (obviously some things are easier to do in pigs....but you get the idea).

Secondly the article opens talking about hypovolaemia "contribut[ing] to intestinal hypoperfusion and subsequent postoperative complications" but this study is unable to address the question of clinically significant postoperative complications. Does pentastarch change these or just the numbers?

At the moment this is certainly not going to alter my management of trauma (NS for resus and if they need colloid they get blood), but it might make me think about the next non emergent laparotomy I do (before sticking with my original crystalloid plan..esp as we don't have pentastarch at my hospital, just gelofusine).
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I'm going to address your comments in bold.

It's always helpful to read the goal and conclusions of a study (at least) and try to understand why this study was done and published when evaluating it.

The study does not attempt to provide data on postoperative outcomes, so you cannot fault it for not doing so; the study does not attempt to change your clinical practice in trauma or elsewhere, so you cannot fault it for not doing so.

What it does do is attempt to provide a valid scientific basis for a later, bigger, human outcome study on colloids vs. crystalloids. This sentence, from the conclusion in the abstract, is a dead giveaway: "These results support the notion that perioperative goal-directed therapy with colloids might be beneficial during major abdominal surgery." As you know those kinds of human outcome studies are expensive and time-consuming and best done with as much theoretical support from small, non-outcome, possibly animal, studies as possible.
 
had a good article a couple months back in Current Opinion in Anaesthesiology too. Similar take as the other one, but related more toward vascular surgery patients.
 
fakin' the funk said:
This article is fantastic. It's a bit hefty but you'll need to know it in order to refute the surgeons always yakking about their patients "third spacing." The endothelial glycocalyx stuff blew my mind. My impression is that the fluid management approach it supports is pretty conservative.
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Who thought you'd ever have to read about the glycocalyx again after first year of med school? :laugh:
 
After reading the full article, I doubt the pig is a good model (their SVO2 is pretty low, and doesn't seem to have much reserve). Do these outcomes really mean anything? I doubt it. And, we do have clinical trials that show restricting fluid in bowel (and thoracic) cases improves outcomes that we care about.
 
fakin' the funk said:
I'm going to address your comments in bold.

It's always helpful to read the goal and conclusions of a study (at least) and try to understand why this study was done and published when evaluating it.

The study does not attempt to provide data on postoperative outcomes, so you cannot fault it for not doing so; the study does not attempt to change your clinical practice in trauma or elsewhere, so you cannot fault it for not doing so.

What it does do is attempt to provide a valid scientific basis for a later, bigger, human outcome study on colloids vs. crystalloids. This sentence, from the conclusion in the abstract, is a dead giveaway: "These results support the notion that perioperative goal-directed therapy with colloids might be beneficial during major abdominal surgery." As you know those kinds of human outcome studies are expensive and time-consuming and best done with as much theoretical support from small, non-outcome, possibly animal, studies as possible.
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I agree with you entirely - my whole point was that whilst this research is interesting....we need more before it is going to alter my practice. 🙂
 
I thought the Anesthesiology article was interesting, primarily because the seemed to spend a lot of time saying, "Study A says this, and study B showed the opposite." I think fluid management is like many subjects. At first it seems complex, then you learn an little bit and you think it's easy, then you learn a bit more and you see how complex it really is. How do you monitor volume status and fluid responsiveness? UOP? BP? CVP? Start digging into the literature and you'll be surprised at the crap that has been passed on as gospel truth.

I think it's going to be very difficult to generalize rules because the underlying biological system, i.e., a human patient, is quite complex with an incredible number of variables. Fluid management for a healthy athlete getting a knee scope is not a big deal. Fluid management for someone with diastolic dysfunction (pseudonormalized or restrictive LV Doppler filling) can be much more challenging. Even those with impaired relaxation can be challenging because you don't know how much fluid it's going to take to push them into more severe diastolic dysfunction. I think that we will eventually see that many anesthesiologists frequently give more fluid than is needed.

One of the big challenges in assessing the quality of our fluid management is the temporary nature of our encounters with out patients. We get them to PACU extubated with their pain relatively controlled, and it's a success. We may see them POD 1 for a post-op visit. We frequently don't know if they came back to the hospital in the first post-op month in A-fib or with CHF symptoms. I expect if you looked, you would find many more than you think. I think that a significant portion of that can be traced back to our intraop fluid management.
 
This study is not for anyone to alter their practice but it's just one more thing showing that the Colloid versus Crystalloid battle is far from being settled.
I predict that in the near future we are going to see a return of Colloids usage as part of a new approach to intra-op fluid management.
 
proman said:
And then we'll have the surge of anaphylactoid reactions from the hetastarch.
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Although this is not the main issue here but I have to say that anaphylactiod reactions to Hetastarch are rare, nothing like the ones seen with Dextran.
I know that there are case reports in the literature but I have given Hetastarch hundreds or maybe thousands of times and never seen one anaphylactoid reaction.
 
Agree that it's rare, but if the number exposed goes up so does the prevalence. We've been making an effort to reduce the amount of fluid given to the posterior spine fusions for pediatric scoliosis. A lot more colloid has been given. A colleague encountered hypotension, minimal increase in HR, no change in airway parameters. Presented just like hypovolemia, so he gave hetastarch. Pressure kept going lower, gave more hetastartch. Pressure got to near peri-arrest levels, got some epi and everything normalized. I realize it's n=1 but certainly interesting to see how this particular scenario can delay diagnosis of anaphylactoid shock. What about repeat exposure? Does that increase the risk?
 
proman said:
Agree that it's rare, but if the number exposed goes up so does the prevalence. We've been making an effort to reduce the amount of fluid given to the posterior spine fusions for pediatric scoliosis. A lot more colloid has been given. A colleague encountered hypotension, minimal increase in HR, no change in airway parameters. Presented just like hypovolemia, so he gave hetastarch. Pressure kept going lower, gave more hetastartch. Pressure got to near peri-arrest levels, got some epi and everything normalized. I realize it's n=1 but certainly interesting to see how this particular scenario can delay diagnosis of anaphylactoid shock. What about repeat exposure? Does that increase the risk?
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Well, If we were talking anaphylactoid then it's usually not IGE mediated and is usually caused by direct effect on mast cells so I wouldn't expect repeat exposure to have a role.
On the other hand there is a notion of increased reactions in patients allergic to corn and this could be a real anaphylactic reaction not anaphylactoid which makes repeated exposure a concern.
So the answer is: it's possible!
🙂
 
Bah.

Colloids are $hit. They buy you time until the blood gets there sometimes. Only time to albumin them is in a cirrhotic with SBP or status post ascites drainage greater that 5 liters.

All the studies about using hypertonic saline and all manner of starches have been disappointing, and yes, that includes trauma. In fact starches can be dangerous and really have very little value.

You should see me slugging it out with my medicine people concerning LR vs NS. Jesus. These guys friggen love NS. When I really want to get on someones nerves I order Plasmalyte. =)
 
I also rarely use synthetic colloids in my practice. I am curious what colloids people use in their practices now that pentastarch and tetrastarch solutions are available in the U.S.

What synthetic hydroxyethyl starch is used most commonly at everyone's institutions?

Me-Hetastarch in saline solution is the only hydroxethyl starch available at my hospital. I rarely use it.
 
BISof60 said:
I also rarely use synthetic colloids in my practice. I am curious what colloids people use in their practices now that pentastarch and tetrastarch solutions are available in the U.S.

What synthetic hydroxyethyl starch is used most commonly at everyone's institutions?

Me-Hetastarch in saline solution is the only hydroxethyl starch available at my hospital. I rarely use it.
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Voluven.
 
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