Hi there this is Tammy with NurseMinder and in today's video
we are talking about tic-tac-toe you know that game you used to play as a
child well maybe you still play it we're
actually going to bring that forward and it's another method to analyzing
your acid base imbalances and we're going to take care of that
right after this
Welcome back my name isTammy and this is NurseMinder and on this channel we
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Welcome back in this video we're going to talk about a method
of analyzing acid-base imbalances called the tic-tac-toe method.
Now before we can actually start using the tic-tac-toe, I know it looks like a
lot of fun, we are going to get there, we need to
recall some of our theory first. So we're actually going to
review our normal values for those three elements that we're
looking for to determine our acid base balance. Now the first thing is pH the
overall acidity of the blood the normal range is between
7.35 and 7.45 the acid is on the lower end so if we
get lower than 7.35 it becomes acidotic
I'm just going to put a little a on this side to remind me
and if i get higher than 7.45 we call it basic.
Now our PaCO2 stands for our partial pressure of arterial
co2, carbon dioxide, this represents the hydrogen ions.
I'm just going to put a little note here
hydrogen ions are a positive element, the more positive we have the
more acidic our environment so when it comes to our
PaCO2 if I have too little hydrogen ions
available I'm actually basic
and if I have more than I need of hydrogen ions it's going to become more
acidic
our bicarb is looking at the negative anions
so if I have lots of negative anions I'm greater than 26
I'm more basic
and if I'm a little deficient I've got less than 22 I'm going to be acidotic
so now that we've just reviewed those three elements and which side
of them becomes acid and base it's time to look at our tic tac toe.
So identifying if your acid base imbalance is respiratory or
metabolic, I'd like to offer you this diagram
the PaCO2, CO2 is a reflection of how well our
lungs are working so that would be respiratory
It's a reflection of the respiratory system
HCO3 is a reflection of the kidneys and how well they are able to maintain that
positive negative ion either retention or excretion and so
this becomes metabolic.
So we have a patient's results in front of us
a pH of 7.48 partial arterial CO2 of 38 and bicarb is 29.
So much like when we played tic-tac-toe as kids
only we used x's and o's then right so you would take turns filling this in
until somebody got a straight line, we're going to do the same thing here we're
looking for our values to line up to help us
determine if we are acidotic or alkalotic.
Alkalotic is the term we use when we have too much base in the blood
So if we look at our pH of 7.48 I come back to my normals and I see
7.48 is higher than normal and it's on the basic side so i'm going to put my pH
in here
I also have a PaCO2 of 38. PaCO2 it's normal it's between 35 and 45
so I'm going to put that in here
and then my bicarb is 29. it's higher it's also basic so i'm going to put that
in here
now what I can see is I have my pH lined up with my
bicarb this is telling me that I do have an alkalotic state, I'm just going
to write that down.
base means alkalotic so now I can determine
which imbalance I hav. The kidneys are driving
the imbalance which is alkalotic so I would say I have a metabolic
alkalosis
The next thing I want to know is - is my body
compensating? So how do I know if it is? Because it is metabolic, our kidneys are
driving it, we would expect to see that the lungs
help support the body by working in opposition to maintain
that acid-base balance in the body but because my respiratory values are
still normal I haven't seen that shift
now if we were to see that shift let's just change
the CO2 and we'll say it's now 32
that's gonna move my my lungs over to the acid side
so then the question becomes is this compensated? Now partially compensated simply means that
both systems are working but the pH has not come back to normal and when I look
at this I see my pH is still basic it's still too high
so this would be considered partially compensated the lungs have kicked in
they're trying to help out. Let's say it's been two more days,
two more days sure why not, so we've redone our blood test and it comes back
now and we are 7.38 and we'll leave those two values at 32
and 29. well 7.38 is now within normal so I'm
going to move my pH
over here. Now I don't have a tic tac toe I don't have three
things lining up but I do have a normal pH
so this is telling me that these two systems that are out of balance right
now are working to maintain a normal
environment for cellular function. The question is which one is still
driving the imbalance and which one is correcting?
To understand that we need to know a little bit more about our pH.
When we look at 7.35 to 7.45 the middle point
is 7.40
if my pH is on the acid side then we would consider
the other matching acid, if my pH was 7.40 and higher towards the basic side
I would look then for the basic system to determine which
which system is driving the imbalance. So in this case 7.38
is on the acid side I would say I have a respiratory acidosis that is
that is compensated, a compensated respiratory acidosis.
Let's try another one okay so we have a new patient here and we have our
lab results in our pH is 7.30 our PaCO2 is 46 and our bicarb HCO3
is 29. So let's plunk these in. My pH is on the lower side it's
too low so we know that's acidic so we'll put our pH, our Paco2 is 46,
it's on the higher side that means I have a lot of hydrogen ions,
positive acid so I know my PaCO2
is acid I still want to finish this all the way out though I can't just stop
here my bicarb is 29 bicarb is
base it's the negative ions it's high which means I am basic
in bicarb so I'll put that over here
now looking at this I can diagnose that I have a respiratory
acidosis and that the kidneys the metabolic system is
trying to kick in and help bring us back to normal
but it is not compensated yet so this would be considered a
respiratory acidosis with partial compensation because the kidneys
have moved into that base side to balance off the lungs. Let's do
one more. So in our third example, we have a pH of
7.42 a PaCO2 of 36 and a bicarb of 24. so
let's start to plunk those in. You should be starting to recognize
your normals, you really should commit these normals
to memory, there are three sets of numbers acid
base which one's respiratory which one's kidneys
that should be part of your memorization for this.
7.42 i know this is normal so I'm going to put my pH
in my normal, PaCO2 is 36. I also know this is normal
and my bicarb is 24 which is also normal oh my gosh i don't have anybody with an
acid base imbalance. So the next time they say you shouldn't
be having fun at work you just pull out that tic-tac-toe board and you show them
how much fun interpreting acid-base balances can
be. Don't forget to comment below let me.
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and as always I thank you for joining me and until next time
make it a great day :)