Crystalloid in trauma hypovolemic shock?

[HMartinho]

What kind of crystalloid do you prefer to use in hypovolemic shock in trauma calls, when you are on an unit who have no blood units (ILS)?

 

[NomadicMedic]

LR.

 

[STXmedic]

None if it all possible.

LR if absolutely necessary.

 

[Summit]

Plasmalyte... or LR... but actually NS in the field because it is what we have... and we are probably in the field since we are giving crystalloids for hypovolemic shock.

Now if this is not hemorrhage but rather due to dehydration/DKA/over-diueresis/hyperemesis types of hypovolemia etiologies, then I definitely choose NS.

 

[Carlos Danger]

Doesn't matter much at all.

Large volumes of NS result in a lower pH and possibly a hyperkalemia. Some studies show more tendency towards coagulopathy, as well.

However, my understanding is that studies have shown no difference in mortality. So it's one of those things where the numbers might make you feel better, but the eventual outcomes are the same.

So most of us will use LR, because it does look better on paper. But if someone is bleeding bad enough to need large volume resuscitation, the only thing that really helps is blood.

Moderator Note: Changed NS to LR per user's request.

 

[Hold My Beer]

LR appears to be more beneficial over NS due to the electrolytes it contains. I remember reading that electrolyte infusion prior to blood replacement is better for the patient. With that in mind you are offering the patient a better chance of living once they can get some blood at the hospital. However, many agencies do not carry LR so your stuck with warm bags of NS.

Unless the trauma patient is burned I believe fluids should be used cautiously. Many argue that fluids are only beneficial if 1. The patient is bleeding at a rate of 25-100 mL/Min 2. IV infusion rate is equal to the rate of bleeding. 3. Scene and transport time exceeds 30 minutes. This, I believe, is hard to nail down especially with suspected internal bleeds.

The ****ty part about hemorrhagic shock is that once you can see clinical signs like low bp, tachycardia, and DLOC your already too late and the patient will have lost 20-40% of their total blood volume and no amount of LR or NS will get that patient back. GET TO DA CHOPPA!

 

[Carlos Danger]

LR appears to be more beneficial over NS due to the electrolytes it contains. I remember reading that electrolyte infusion prior to blood replacement is better for the patient.

Sources?

 

[Bobbob1354]

The crystalloid infusion are beneficial at first, they will increase cardiac output. Direct infusion of packed RBC and whole blood will increase the viscosity of the blood and decrease cardiac output.

Fluid resuscitation
Total body volume
Male = 66mL/kg
Female = 60mL/kg
Estimate loss of blood
Class 1: Less than 15%
Class 2: 15 to 30%
Class 3: 30 to 40%
Class 4: Greater than 40%
Find volume deficit
VD= BV x Blood loss %
Resus volume
RV= VD x 4 (for crystalloid)


Correction goals of Hypoperfusion
VO2 = Q x Hb x (SaO2-SvO2)

The ICU Book 3rd edition

Paul Marino

A lot of interesting ideas are presented in this book.

 

[MonkeyArrow]

The crystalloid infusion are beneficial at first, they will increase cardiac output. Direct infusion of packed RBC and whole blood will increase the viscosity of the blood and decrease cardiac output.

So are you suggesting that we should give crystalloids, even if blood products are available for resuscitation?

 

[Bobbob1354]

Yes, the idea seems to be supported in that literature, from what I have gathered at least.

 

[Carlos Danger]

The crystalloid infusion are beneficial at first, they will increase cardiac output. Direct infusion of packed RBC and whole blood will increase the viscosity of the blood and decrease cardiac output.

CO is usually already high in someone with class 2 or higher blood loss. Tachycardia and vasoconstriction is the body's classic response to reduced perfusion.

But if someone is actively bleeding, is increasing the cardiac output a good thing?

Take a garden hose, and cut a small hole in it. Now turn the water on at low pressure. You'll see a small trickle out of the hole. Now turn the water pressure up higher. What happens? The hole leaks much faster. Now imagine that garden hose is an artery, and the water is blood, and the water pressure is blood pressure. You can see why keeping the blood pressure high is not necessarily beneficial.

Giving large volumes of crystalloid does two harmful things to someone who is actively bleeding: First, it increases vascular pressure, which the hose experiment showed us is not helpful because it will speed blood loss. Second, it reduces the concentration of red blood cells which we need to transport oxygen, and platelets and clotting factors, which are necessary for the bleeding to stop and to prevent coagulopathy.

You do have to maintain a minimum MAP in order to perfuse the coronary arteries and the brain and the other vital organs. And if crystalloid is the only fluid you have, then you do what you can with what you've got. So the idea there is to use as little crystalloid as possible to keep the MAP at a level that will allow vital organ perfusion (say, a MAP of 60). Any higher than that and you are diluting unnecessarily and increasing pressure at the wound unnecessarily.

The current thinking in trauma resuscitation where more than half the blood volume has been lost is to use as little crystalloid as possible, if you have a choice. The ideal fluid is whole blood. Since that is rarely available, a 1:1:1 ratio of PRBC's, platelets, and FFP is the next best thing, using just enough crystalloid to KVO. Once the bleeding is surgically controlled and the hemoglobin and platelets are at acceptable levels, crystalloid can be used to expand the blood volume.

Search the literature and you'll see that this general approach is what most of the research from the past decade or two (much of which is from the military's experience in Iraq and Afghanistan) points towards.

There is also some newer thought about using vasopressors earlier in traumatic shock. I don't know the rationale behind that as it seems to run counter to what I just described, and I don't know if that approach will end up being supported by research. Just something I've heard some low rumblings about here and there.

 

[Nova1300]

The crystalloid infusion are beneficial at first, they will increase cardiac output. Direct infusion of packed RBC and whole blood will increase the viscosity of the blood and decrease cardiac output.

Fluid resuscitation
Total body volume
Male = 66mL/kg
Female = 60mL/kg
Estimate loss of blood
Class 1: Less than 15%
Class 2: 15 to 30%
Class 3: 30 to 40%
Class 4: Greater than 40%
Find volume deficit
VD= BV x Blood loss %
Resus volume
RV= VD x 4 (for crystalloid)


Correction goals of Hypoperfusion
VO2 = Q x Hb x (SaO2-SvO2)

The ICU Book 3rd edition

Paul Marino

A lot of interesting ideas are presented in this book.

That book is a great primer for ICU care. However, often he tries to simplify things that just aren't that simple. For example, to say that direct infusion of whole blood and RBCs will increase viscosity and decrease cardiac output is a little absurd. Yes, in a pig model in the laboratory where the infusion of RBCs exceeds the experimental blood loss, the hematocrit will increase. And, since the hematocrit is the primary determinant of blood viscosity, it too will increase. But, in a trauma resuscitation, the clinical effect of the frank starling curve is far more important. Increasing the preload (by whatever means, blood, fluid, etc) will be far more impactful on cardiac output that any increase in blood viscosity.

And, the pig lab is not really how the world works. If you are losing blood faster than it is given, the hematocrit will not increase. If you are giving crystalloid or plasma or platelets with your blood, the hematocrit may remain the same or decrease.

Nearly all patients in hemorrhagic shock will have a compensatory increase in heart rate to counterbalance the loss of stroke volume. Combined with pain, fear, inflammatory response and catecholamine release, most of these patients are actually hyperdynamic (have a high cardiac output). If cardiac output is low in a trauma patient, it is because you are way behind in resuscitation or the patient is in heart failure, not because the blood has become too viscous.


I like Marino, but the reason we have this debate about crystalloid and blood every few years is because its not as simple as a couple lines in a textbook and an equation or two. And to be honest, my own opinion is that resuscitation is a dynamic process and the optimal resuscitation fluids change as the patient's physiology changes. This hunt for the "right" trauma recipe will likely continue for years, because Im not sure that there is a single "right" answer. The best resuscitation outcomes are probably more dependent on having someone in the room that understands oxygen consumption and delivery, cardiac output and how to augment it, acid-base balance, coagulation, end-organ perfusion, medical comorbidities, etc. and having that person guide the resuscitation while the surgeon plugs the hole.

But, really, its a pretty cool book as a starting point. Just don't take it as gospel truth.

 

[Akulahawk]

What kind of crystalloid do you prefer to use in hypovolemic shock in trauma calls, when you are on an unit who have no blood units (ILS)?

Of the two commonly found fluids that we find in field units, I'd choose LR over NS. That being said, I'm not going to flood this kind of patient with fluids. Diluting whatever blood is left in the patient into something resembling Kool-Ade isn't doing the patient any good and neither is increasing fluid levels to the point where clots that have formed pop off the holes they've plugged doesn't help either. Given that I'm going to be very judicious in my fluid resus, either LR or NS will do just fine. Once in the ED, I'm still going to want to keep the patient dry until I can get the patient to a trauma surgeon. Not all facilities have surgeons that are comfortable doing damage control surgery...

 

[Carlos Danger]

That book is a great primer for ICU care. However, often he tries to simplify things that just aren't that simple.

I like Marino's book also. It was like the bible to me (along with the ASTNA textbook) when I was flying. I still recommend it to paramedics and nurses who are just getting into critical care.

But....there are a couple weird things in it. Like this section at the end of Chapter 19 in the 4th edition:

Blood Volume vs. RBCs

The practice of transfusing RBCs to raise the Hb level in blood is rooted in the belief that anemia is a threat to tissue oxygenation. However, as described earlier in the chapter, the severest anemias do not threaten tissue oxygenation as long as the intravascular volume (and hence cardiac output) is maintained. The supremacy of blood volume over RBCs in supporting tissue oxygenation is evident when you consider that hypovolemia is a recognized cause of impaired tissue oxygenation (i.e., hypovolemic shock), but anemia is not (i.e., “anemic shock” is not a clinical entity). The importance of blood volume is often overlooked, even by the American Red Cross, whose popular slogan, blood saves lives, deserves a more accurate update, as shown in Figure 18.7. Awareness of the attributes of blood volume would help to curb the undeserved emphasis on the transfusion of RBCs to support tissue oxygenation.

What?

 

[Summit]

Marino's book is great. I have my own copy of 3rd edition.

But the evidence in the 3rd edition is all pre-2005 at best.

 

[Nova1300]

I like Marino's book also. It was like the bible to me (along with the ASTNA textbook) when I was flying. I still recommend it to paramedics and nurses who are just getting into critical care.

But....there are a couple weird things in it. Like this section at the end of Chapter 19 in the 4th edition:



What?

I had that same response in multiple parts of the book.


But, overall certainly a worthwhile read.

 

[Brandon O]

I like Marino's book also. It was like the bible to me (along with the ASTNA textbook) when I was flying. I still recommend it to paramedics and nurses who are just getting into critical care.

But....there are a couple weird things in it. Like this section at the end of Chapter 19 in the 4th edition...

While a rather idiosyncratic way to look at things (as is his wont), it's true that anemia per se is often well tolerated. We have not really seen evidence that transfusing blood for any physiological target you care to choose (hemoglobin, lactate, venous sats, symptomatology, etc) improves outcomes. (For example, we tend to transfuse for Hgb <7 because it's been shown to be equivalent to <10, not because it's been shown to be superior to <6, or <5, or...) Obviously acute hemorrhagic shock is probably a different animal, but we have to grant that we'll probably never have the evidence to fully tease apart the separate tasks of replacement of oxygen carrying capacity with the replacement of cardiac output and replacement of hemostatic components and so on.

 

[Carlos Danger]

While a rather idiosyncratic way to look at things (as is his wont), it's true that anemia per se is often well tolerated. We have not really seen evidence that transfusing blood for any physiological target you care to choose (hemoglobin, lactate, venous sats, symptomatology, etc) improves outcomes. (For example, we tend to transfuse for Hgb <7 because it's been shown to be equivalent to <10, not because it's been shown to be superior to <6, or <5, or...) Obviously acute hemorrhagic shock is probably a different animal, but we have to grant that we'll probably never have the evidence to fully tease apart the separate tasks of replacement of oxygen carrying capacity with the replacement of cardiac output and replacement of hemostatic components and so on.

True, but we obviously need some hemoglobin. Clearly there is some level at which oxygen delivery is negatively affected in a clinically important way. The way that passage is worded though, implies that we don't need any hemoglobin level. Just strange wording, I guess.

The body has ways of increasing oxygen extraction when supply falls, as you know. The fact that a trigger hasn't been identified probably has more to do with the fact that the efficacy of these mechanisms varies from individual to individual and clinical condition to clinical condition than it means that hemoglobin level doesn't matter at all.

 

[Hold My Beer]

Sources?

PHTLS 8th edition. page 221

 

[Worminger]

Hey,

I'm new in this forum. Can anyone write out the types of the infusions please? Because it's not easy for one from Germany. ;-) thank you!