Widened pulse pressure

xtxrn, ASN, RN · Oct 25, 2011

Neuro text/chapter :)

Cushings' triad is not the same as the adrenal disorder "Cushing's Syndrome"

It is CRITICAL to know the difference- and this is basic neuro information in a textbook- you probably have the answer very nearby :up:

AgentBeast, MSN, RN · Oct 25, 2011

Widening pulse pressure> Neuro

Narrowing pulse pressure> Cardiac

ithalia77 · Oct 25, 2011

@ Old goat. thank you for taking the time to tell me its in a book- I couldn't really find anything in my text about widening pulse pressure. This morning though i surfed the web and read on it. I thought that this was a forum where we could post questions and get answers and insight. I will continue to seek answers other ways

Also, I didn't think that the triad of symptoms in Cushing's Syndrome was the same as Cushing's Syndrome. I was trying to get an understanding of what it is (which I now Know) and why the pulse pressure widens.

PsychNurseWannaBe, BSN, RN · Oct 25, 2011

@ Old goat. thank you for taking the time to tell me its in a book- I couldn't really find anything in my text about widening pulse pressure. This morning though i surfed the web and read on it. I thought that this was a forum where we could post questions and get answers and insight. I will continue to seek answers other ways
Also, I didn't think that the triad of symptoms in Cushing's Syndrome was the same as Cushing's Syndrome. I was trying to get an understanding of what it is (which I now Know) and why the pulse pressure widens.

Ithalia,

I am thinking Oldgoat was just trying to point you in the right direction. Sometimes what we see here on the website is someone looking for a quick answer instead of taking the time to research it. Now, maybe if you put what you knew and what about something you found confusing, that would help us help you better. It is better if someone posts what they know (even if it is wrong... we will correct you. ) and help guide you to the answer. We like to guide... guide being the key word.

Wishing you the best

~Psych

ithalia77 · Oct 26, 2011

Thank you much. I will keep that in mind.

xtxrn, ASN, RN · Oct 26, 2011

@ Old goat. thank you for taking the time to tell me its in a book- I couldn't really find anything in my text about widening pulse pressure. This morning though i surfed the web and read on it. I thought that this was a forum where we could post questions and get answers and insight. I will continue to seek answers other ways
Also, I didn't think that the triad of symptoms in Cushing's Syndrome was the same as Cushing's Syndrome. I was trying to get an understanding of what it is (which I now Know) and why the pulse pressure widens.

I can't know what you already know :)

And, believe it or not, folks do ask first, and then look things up as a last resort :down:

It was (as PsychNurseWannaBe said) a suggestion- not a put down. :up:

nurseprnRN, BSN, RN · Oct 26, 2011

"also, i didn't think that the triad of symptoms in cushing's syndrome was the same as cushing's syndrome."

as they said, we don't know what you do know. tell us, and tell us what you learned already so we can clear up misconceptions or add some useful hints.

and be fair: saying what you said above could, in fact, lead one to believe that you are conflating cushing's triad with cushing's syndrome. they are not the same and only have the same name because the same guy (cushing) described them first .

so.... where were we? what was your specific question?

xtxrn, ASN, RN · Oct 26, 2011

Yep- what GrnTea said :)

Many of us do want to help y'all out :up:

akulahawkRN, ADN, RN, EMT-P · Oct 27, 2011

As has been said before, Cushing's triad has to do with a neuro problem - a fairly specific type of neuro problem. I would suggest checking google for "cushing's triad" and then look up the associated links on the wikipedia, which is short, but very much to the point.

It's in response to something else... so why would the body shove the SBP really high and slow the heart rate down, with respect to the reflex that triggers the triad?

xtxrn, ASN, RN · Oct 27, 2011

This words it much better than I can.....

http://en.wikipedia.org/wiki/Cushing_reflex

http://en.wikipedia.org/wiki/Cushing%27s_triad

Both are sideways protective mechanisms for increased intracranial pressure, and an indication of the progression of brain herniation. Usually, other symptoms will be seen first (change in LOC, orientation, headaches, vomiting not preceded by nausea, and, if the third cranial nerve is already getting compressed, pupil changes - that's not an early sign, as is often implied with neuro checks..... if someone is talking to you - with no history of eye surgery, the pupils should be just fine....but having an emphasis on pupil checks gives the impression that it's something earlier than it really is).

Check the illustration of the brain, foramen magnum, and position of the cranial nerves as they exit the skull- if they do. That will also give you ideas as to what may be likely to show up as herniation progresses.

The reason patients can be placed on vents is to increase the O2 (duh), but with that comes a cessation of the vasodilation that happens when the brain is starved (or at least hungry) for oxygen. They are usually hyperventilated to help bring things back into stable condition (along with mannitol - or whatever the diuretic d'jour is these days).

I hope this helps- and if not, post the specifics about what isn't making sense, and I'm sure someone will try to help :)

nurseprnRN, BSN, RN · Oct 27, 2011

"the reason patients can be placed on vents is to increase the o2 (duh), but with that comes a cessation of the vasodilation that happens when the brain is starved (or at least hungry) for oxygen. they are usually hyperventilated to help bring things back into stable condition (along with mannitol - or whatever the diuretic d'jour is these days)."

actually, this is incorrect. it is co2 and the acidosis that accompanies it that make for (the undesirable) vasodilation and increased intracranial pressure. brain-injury patients (and remember that surgery is an injury too) are put on ventilators not to increase their oxygenation but to hyperventilate them to blow off co2, thus decreasing intracranial pressure. if you remember your abg class you will remember that hyperventilation does not change arterial oxygenation, but it does decrease paco2.

this is because blood gases are obtained from and exhaled through the capillary bed in the alveolus. remember diffusion? a substance flows from an area of higher concentration to an area of lower concentration? well, the concentration of co2 in inspired air in the alveolus is, for practical intent, zero, so washing it out with faster/deeper ventilation pulls more and more co2 out of the blood.

blood oxygen, on the other hand, can never get any higher than what's in the alveolus (less water vapor pressure and proportional to atmospheric pressure at the altitude)-- breathing faster won't make it go any higher.

this is why hyperventilation makes you feel dizzy and tingly-- it drops your normal paco2 and makes you alkalotic (co2 is an acid), thus confusing your nerves. that's why you have people who are hyperventilating inappropriately breathe in and out of paper bags-- since they are rebreathing air with elevated levels of co2, eventually it reaches a normal level and they restore their acid/base balance to normal.