Malignant Hyperthermia

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Specializes in Critical care.

Hi all,

My med surg professor was lecturing on this today and asked the class why a nonrebreather is appropriate therapy for a post-OR patient who has malignant hyperthermia (in conjunction with other cooling measures, of course). I know the answer involves something about increased oxygen demand but I don't understand WHY. I've read the book and I am still confused. Can someone please clarify?

Thanks in advance! :shy:

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You don't know why the oxygen demand is increased, or you don't know why the non-rebreather is appropriate? Any time the body is in a state of stress, cellular oxygen demand increases. This would happen in a hyperthermic state (just think about how much harder you breathe on a walk in the hot summer than on the same walk in the fall)

As for the mask, take a look at how the non-rebreather works....and the amount of oxygen delivered, and you'll likely find your answer. Hope that helps a bit.

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In order for your body to reach the high temp of a fever (or malignant hyperthermia), it requires increased metabolic demands. In other words you body requires fuel and wood to keep that "fire" going. Think of the oxygen as "fuel." Well, just like a fire eats up O2... so does your body when it increases its metabolic process to get its temp up. When your body requires more O2, it puts an increase demand on your heart. This is why tachycardia accompanies a fever. Your heart pumps faster to get more oxygen to the cells that are now burning fuel to maintain a high temp. By placing a pt on O2, you lower this demand and "help out" the heart. You use a non-rebreather, because it is the only mask that can deliver 100% O2 (or pretty darn close- I've heard that no mask can actually deliver 100%). So...

-High Temp = increase metabolic demand

-Increase metabolic demand = I want more oxygen (cells need fuel)

-Heart speeds up to meet this increase demand of oxygen

-Non rebreather at 15 LPM provides extra O2

-Heart now has back up!! Cells get their fuel!!

Hope this helps.

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Specializes in None yet..
In order for your body to reach the high temp of a fever (or malignant hyperthermia), it requires increased metabolic demands. In other words you body requires fuel and wood to keep that "fire" going. Think of the oxygen as "fuel." Well, just like a fire eats up O2... so does your body when it increases its metabolic process to get its temp up. When your body requires more O2, it puts an increase demand on your heart. This is why tachycardia accompanies a fever. Your heart pumps faster to get more oxygen to the cells that are now burning fuel to maintain a high temp. By placing a pt on O2, you lower this demand and "help out" the heart. You use a non-rebreather, because it is the only mask that can deliver 100% O2 (or pretty darn close- I've heard that no mask can actually deliver 100%). So...

-High Temp = increase metabolic demand

-Increase metabolic demand = I want more oxygen (cells need fuel)

-Heart speeds up to meet this increase demand of oxygen

-Non rebreather at 15 LPM provides extra O2

-Heart now has back up!! Cells get their fuel!!

Hope this helps.

I sure hope that somewhere, somehow, in addition to allnurses, you are teaching students. Thanks for the clear and complete explanation.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
In order for your body to reach the high temp of a fever (or malignant hyperthermia), it requires increased metabolic demands. In other words you body requires fuel and wood to keep that "fire" going. Think of the oxygen as "fuel." Well, just like a fire eats up O2... so does your body when it increases its metabolic process to get its temp up. When your body requires more O2, it puts an increase demand on your heart. This is why tachycardia accompanies a fever. Your heart pumps faster to get more oxygen to the cells that are now burning fuel to maintain a high temp. By placing a pt on O2, you lower this demand and "help out" the heart. You use a non-rebreather, because it is the only mask that can deliver 100% O2 (or pretty darn close- I've heard that no mask can actually deliver 100%). So...

-High Temp = increase metabolic demand

-Increase metabolic demand = I want more oxygen (cells need fuel)

-Heart speeds up to meet this increase demand of oxygen

-Non rebreather at 15 LPM provides extra O2

-Heart now has back up!! Cells get their fuel!!

Hope this helps.

well said!

OP think about this logically...What is malignant hyperthermia? medscape: you need to register but completely free

Malignant hyperthermia (MH) is a life-threatening clinical syndrome of hypermetabolism involving the skeletal muscle. It is triggered in susceptible individuals primarily by the volatile inhalational anesthetic agents and the muscle relaxant succinylcholine, though other drugs have also been implicated as potential triggers.[1] MH is not an allergy but an inherited disorder that is found both in humans and in swine.

This hypermetabolism causes increased carbon dioxide production, metabolic and respiratory acidosis, accelerated oxygen consumption, heat production, activation of the sympathetic nervous system, hyperkalemia, disseminated intravascular coagulation (DIC), and multiorgan dysfunction and failure. Early clinical signs of MH include an increase in end-tidal carbon dioxide (even with increasing minute ventilation), tachycardia, muscle rigidity, tachypnea, and hyperkalemia. Later signs include fever, myoglobinuria, and multiorgan failure.

what are the symptoms of malignant hyperthermia?
The typical symptoms of malignant hyperthermia are due to a hypercatabolic state, which presents as a very high temperature, an increased heart rate and breathing rate, increased carbon dioxide production, increased oxygen consumption, acidosis, rigid muscles, and rhabdomyolysis
This is why the patient needs more fuel and support.
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Specializes in Critical care.

OOOOOOOOHhhhhhkay. I completely get it now, and TraumaDreams, I agree that you should totally be a professor. What a great explanation! I understood the nonrebreather mask from the get-go, but wasn't thinking about the hypermetabolism and therefore increased O2 demand from cells. That makes complete sense. Thanks everyone!

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
OOOOOOOOHhhhhhkay. I completely get it now, and TraumaDreams, I agree that you should totally be a professor. What a great explanation! I understood the nonrebreather mask from the get-go, but wasn't thinking about the hypermetabolism and therefore increased O2 demand from cells. That makes complete sense. Thanks everyone!
You are welcome.....you are from my stomping grounds. I'm a Purdue grad.
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