We’re going to go for some tools, some disturbances
and how the body compensates for them.
Here the first tool we’re going
to use is the Acid-base Box.
Acid-base boxes are a nice
simple way to look at a disorder.
Now, disorders are going to be
things like acidosis and alkalosis.
These are the conditions that you’ll
get to have an acidosis or an alkalosis.
So, you might have a respiratory
acidosis or a metabolic acidosis
or a respiratory alkalosis
or respiratory acidosis.
Those –osis portions are the
condition that is involved.
If we want to look at blood pH,
we call an –emia.
So, you could have an acidemia or an alkalemia.
For a metabolic component, we’re only
really looking at bicarb levels.
We have the edges of the box at
22 millimole and 28 millimole.
Although, 24 to 25 millimole is what we would
normally see. We give it a little bit of a range.
Our respiratory component, is PaCo2, which is
the partial pressure of arterial carbon dioxide.
Here, we have to do something pretty
crazy and we have to flip around
our lefts to rights to make this work out.
We’re going to have 48 PaCO2 and 32 PaCO2.
If we want to use our first example,
so let’s just go through one of these.
just to go through the naming process
of which condition might be involved.
If we did an arterial blood gas measurement,
and we got a pH of 7,62
that would give us a blue gnome outside the box.
A bicarb of 18 gives us a red gnome
outside the box on the acidosis side.
And finally, a CO2 value of 18 gives us
a blue gnome on the alkalosis side.
This is the beauty of an Acid-base box
because we can name this disorder.
If they have this arterial blood gas,
you could look at the Acid-base box and say
‘’Respiratory alkalosis’’. Why?
Cos there are two gnomes on one side.
that’s how the naming goes,
We might ask what do you do with
that gnome on the opposite side?
He was an acidic gnome, why is he out there
on the bicarb side?
Well, just so happens that the body is trying
to compensate for the respiratory alkalosis.
So, if we are going to name that, it would be
a respiratory alkalosis with metabolic compensation.
That naming process all works with
these simple acid-base boxes.
I know right now you’re going to
‘’What is he talking about?’’.
Let’s go through another example.
Let’s say we have a pH of 7,59 obtained
through an arterial blood gas.
Blue gnome outside the box.
We get a bicarb value now of 24.
So, now we’re going up through
a green gnome inside the box.
Why is he inside the box?
Because you’re going from 25 to 22,
you’re somewhere within that range.
If you’re below 22, you’ll be
outside the box.
In the box, because it’s within
the 22 to 25 range.
Finally, PCO2, 26 millimeters of mercury,
that’s another blue gnome outside the box.
So, of course we can name this.
We can name this disorder,
it is a respiratory alkalosis without
Why do I know that?
Two gnomes on the same side outside the box.
That’s how the naming works.
Why did I know there was not
a lot of metabolic compensation?
Because if the body was trying to compensate,
they would have put the gnome outside the box.
If the gnome is in the box, no compensation yet.
Outside the box, would have got some compensation.