MAP

[cfaulknor]

Today in Paramedic Class we learned about the mean arterial pressure, how to calculate it based on blood pressure, and its applications in critical trauma care.

My question is... in what situations do you providers out there find it most valuable? Is it something you personally choose to use on every call?

[chbare]

MAP measurements can be used in many situations; however, like any measurement, it is just a number and must be taken into context to the patient's condition. An example of one situation where you can use MAP's to help guide treatment is a head injury. A MAP of 70-100 or more may be helpful with the maintenance of CPP. If you remember the formula for CPP, then you see how MAP can be an important factor in head injury management. On common mistake I see is people treating the HTN associated with head injuries and reducing the MAP.

Take care,

chbare.

[FL_Medic]

Today in Paramedic Class we learned about the mean arterial pressure, how to calculate it based on blood pressure, and its applications in critical trauma care.

My question is... in what situations do you providers out there find it most valuable? Is it something you personally choose to use on every call?

It is actually a more important number than your systolic. Well, that is what I have been told by many docs, but it is difficult to apply it to your protocols if you have only systolic paramaters. The only time I have seen it used as a paramater in a EMS protocol is the hypothermia for ROSC which is the last topic I posted. Other than that I have not seen a medical director implement MAP as a starting/stopping point for any medications in the prehosital setting.

[Ridryder 911]

I believe that MAP is not understood and used enough. Like ChBare, I use it on CHI:ICP, as well many other illnesses and injuries. Remember, MAP is a good indicator or perfusion pressure to both coronary and systemic circulation.

R/r 911

[OVeractiveBrain]

I think that section was more to make you aware that blood pressure and perfusion are not the same thing, and to be wary when dealing with trauma. The ability to approximate the MAP using diastolic and systolic pressures, while present, is rather superfloous, in my opinion. While a blood pressure is one form of diagnostic tool to measure perfusion, clinical finidings are often more important than a calculation based on one diagnostic tool.

The use of MAP in paramedic education is to give you insight into a field that we deal with regularly, i.e. trauma. Conceptual understanding of lack of perfusion and tissue failure is an important concept with trauma. While they could say "look for signs of shock" like in EMT school, the paramedic is given greater insight into the understanding of the physiologic mechanism of the pathology.

Basically, its a tool used to teach you better, so you know it better, and will remember it better, and probably practice better.

It also sets up the theoretical arguement for hemmoraghic strokes; without understanding MAP, you cannot discuss Cerebral Perfusion Pressure.

When it comes down to it, the academic discussion of MAP is an educational tool, not necessarily a significant diagnostic application.

[fiznat]

When it comes down to it, the academic discussion of MAP is an educational tool, not necessarily a significant diagnostic application.

I agree completely. If I were to be asked "do I calculate MAP on all of my trauma patients" the answer would be no. If I were instead asked "do I think about MAP and it's implications for systemic perfusion," the answer would be yes. It isn't a number as much as it is an important concept that should help direct your care through (patho)physiological understanding.

[Ridryder 911]

There really is a reason MAP is used in the critical care arena. It is not that difficult to calculate (MAP = [(2 x diastolic)+systolic] / 3), and not understanding it and the implications does reflect not having a full understanding of physiological responses; such as problems in end organ systems failure. Having a working knowledge in other perfusion criteria; can be used far more utilized than in just ICP, from a head bleed. Other indicators such as sepsis, and varying degrees of poor perfusion from cardiogenic to hypovolemia. I far much know the MAP than just the reading of the blood pressures.

Yes, it is very unlikely we are able to monitor true pressures such as having an CVP, or art line in place in the field, however; again we need to be careful on limiting one self just to prehospital care environment. It is a shame such monitors such as impedance monitoring that can measure ejection fraction, etc. is so costly and makes it difficult for the prehospital environment to have.

I guess, I much rather have Paramedics having a thorough understanding of something simplistic such as MAP than to waste teaching non-sense stuff. I still wonder why, we have to go backwards in teaching. In reality, understanding the basics of hemodynamics then obtaining the results. It is so much easier to explain and learn, the foundation first then add upon it.

R/r 911

[OVeractiveBrain]

Actually, mean arterial pressure is:

MAP = (Cardiac Output X Systemic Vascular Resistance) + Central Venous Pressue

Approximated AT RESTING HEAR RATES by MAP = [(2 x diastolic) + systolic] / 3,

At elevated heart rates it becomes easier to approximate as closer to the arithmetic mean between systolic and diastolic pressures.

Again, its not hard to see a person with a hole in their leg with a small fountain (because hes cut a femoral line and has bled out already) taching away at 140. His blood pressure is 80/P (maybe you heard it at 80/40). His MAP is 60. Woopity. 80/P at 140 and bleeding is hypoperfused. I much rather prefer we use clinical findings, not calculations, to identify hypoperfusion.

For you as a medic student, keep it as a learning tool. If you go on to more advanced care somewhere, just remember you learned it, because youll probably go over it again.

[Ridryder 911]

If you go on to more advanced care somewhere, just remember you learned it, because youll probably go over it again.

My point exactly.. it should not be "advanced" even my daughters junior high school biology class was taught this. Albeit, it does not take a rocket scientist to do this job, it apparently confuses many in pathophysiology. Any idiot can tell an arterial bleed and the consequences afterwards... but, to understand why pressure is the way it is in a septic patient or hypoperfused patient, without gross findings may be more taxing.

Just like the first part of the quote was actually the definition of the hemodynamics of a blood pressure, one should be familiar with such., Then not to rely upon such just blunt clinical findings.. which even a non trained person should be able to understand. Again, many times our patients may not have such presentations, this is what separates us from having medical knowledge base and just providing first aid.

R/r 911