# Medical Acid Base and ABGs Explained Clearly by MedCram.com | 4 of 8

welcome to Part 4 of Medical acid-base I

wanted to just review what we had just talked about before and that we’ve got

two different types of metabolic syndromes metabolic acidosis metabolic

alkalosis and that we’ve got for respiratory and the reason why there’s

twice as many respiratory’s is because you have to deal with the situation

where respiratory has no compensation from the kidney and then or very little

compensation from the kidney and then chronic compensation from the kidney

same on the respiratory alkalosis side as well and the key point that we

discovered here is that when the pco2 and the pH are going in the same

direction either up or down the primary pathology is metabolic and

then the opposite is true for respiratory when we see the pco2 and the

pH here for respiratory acidosis is going up and the pH is going down and

for respiratory alkalosis the pco2 is going down the pH is going up again

that’s a respiratory process and what I want to do is kind of put this together

for you in a nice graph especially for those people who are spatially inclined

let’s go ahead and clear this and I want to kind of draw a graph for you and it’s

going to be a graph that hopefully you’ll take with you and you’ll kind of

see the utility in this so it’s just a regular graph with specifically pco2 on

the y-axis and we’ll put you know a middle here which is about 40 and here

pH with the middle of 7.40 okay and we said that there were six different types

of acid-base disorders so let’s talk about let’s put some lines in here so we

can kind of get an idea about what we’re talking about okay so that’s that and let’s go ahead and put a line right

about here and we’ll put one more line and right about here okay so here’s our

graph now we already said that if we had a situation where the pco2 and the pH

were going in the same direction that had to be a metabolic and so let’s go

ahead and label these this one here would have to be what well this line

would have to represent that of a metabolic process because the pco2

as it’s going up so is the pH so we know that this is down here

in metabolic acidosis and why is it acidosis because the pH is low so at

metabolic acidosis tend to push things down in this direction whereas this must

be a metabolic alkalosis okay let’s talk about these other ones so these must be

respiratory the question is which one is a respiratory acidosis so which one’s a

respiratory alkalosis well we know that these two up here must be acidosis

because again they’re lower than the pH and are lower than pH of seven point

four oh and these must be respiratory alkalosis because they’re higher than a

pH of seven point four Oh notice though that this one here has less play in

terms of the pH and so if you were to conclude that this must be a chronic

line here and this must be the acute you’ll be right because again the

chronic allows for kidney compensation and there’s less shift so this would be

a chronic respiratory acidosis and this would be a chronic respiratory

alkalosis and if we go to this one this would be acute respiratory acidosis and

this one down here would be acute respiratory alkalosis and you can kind

of see what this is going to look like now let’s talk about this so as we go

down here let’s talk about the metabolic acidosis first remember what’s going on

in metabolic acidosis bicarb is falling and as the bicarb Falls the pco2 is go

to also fall and when they both fall remember the bicarb is going to fall

further than the pco2 and you’re going to get a low pH so how do you know

you’re dealing with a metabolic acidosis well we have something called winters

formula or winters rules and let me put this in terms of an equation and I’m

going to be talking about these equations so that you could figure this

out now we all know that and I’m just going to sort of right over here off to

the side that we look at the henderson-hasselbalch equation in terms

of hco3 over co2 or the P co2 and we know that things either go up or they go

down or what-have-you and so what I’m going to do is I’m going to tell you for

every single point that one goes up what does the other one do so we know that

down here they’re both going to be going down okay they’re both going to be going

down how much does the bicarb go down well I’ll tell you for every one point

that the bicarb goes down the pco2 should also go down by one point and

that’s how you can tell that what you’re dealing with there is a metabolic

acidosis what about a metabolic alkalosis

well things up here are actually going up and in fact the bicarb is

going up the ratio for up here is for every two points that the bicarb goes up

the pco2 should go up by one point and that’s how you’ll know so what do I mean

remember everything starts off with a 24 and a 40 so here what would this speed

if things were to drop by let’s say four points it would be 20 over 36 okay

alternatively it could also be 14 over 30 so in other words for every point

that the numerator drops the denominator should also drop from this going to

metabolic alkalosis for every two points that the bicarb goes up so let’s pick a

number here let’s say oh I don’t know 30 it went out by 6 points and so the by

the vco2 should go up by 3 points so this would be 43 ok so let’s go and look

at the chronic respiratory situations let’s first of all look at acute

respiratory acidosis so what’s happening in acute respiratory acidosis remember

the lungs are not breathing the pco2 is going up if the pco2 is going up then

here our fraction is going to start from the bottom and here the pco2 is going up

by a lot and we’re not expecting a huge increase in bicarb why is that because

it’s a cute we haven’t had the kidneys the chance to kick in so here the ratio

is 10 for every 10 points that the pco2 goes up the bicarb only goes up by one

point and so what would be a good example here a good example here would

be for instance if this was 50 on the bottom and this would be 25 that would

be acute respiratory acidosis what about in chronic respite

really dosis again same situation we have a fraction however because the

kidney is now kicking in we are expecting to see less of an increase in

co2 without the the kidney kicking in and here it’s for every three points

that goes up on the pco2 the bicarb goes up by one point so

something that we would see here let’s let’s say we had the same kind of ratio

let’s say we had 49 okay that would be nine increase for every three that would

be three of those and so we would add three to that that would be 27 okay

because for 249 that’s nine points 9 divided by 3 is 3 3 times 1 is 3 we add

3 to the 24 we get 27 and that would be the new ratio and that’s how we can tell

let’s go down to these again chronic respiratory alkalosis here the ratio

actually let’s go to acute respiratory as alkalosis remember here what’s going

on the lung is blowing off a tremendous amount of co2 and the kidney has not had

a chance to kick in so for every 5 points that the co2 drops by the pco2

drops by the bicarb is going to drop by 1 point and so let’s look here let’s say

that a good example would be lets say that the pco2 dropped to 30 okay that

would mean that the bicarb would drop down to 22 okay if you’re doing your

mouth right and then similarly over here chronic respiratory alkalosis here the

kidney has been allowed to kick in so we’re not going to get as much co2 drop

per drop in bicarb and so here the co2 is dropping again but for every two

points that it drops the bicarb goes down by one point and so what would that

would mean again if we had a ratio an example where the pco2 had dropped down

to 30 that’s a out going from 40 down to 30 for every

two of those would be five so we drop by five that means that our bicarb would

then be about nineteen so again these are ratios for every one that the the

bicarb or sorry for every one of the bicarb drops here are the pco2 drops by

one and so these ratios here the ones that I’m circling these here are ones to

know for each of these different types of categories because it will help us

later identify if something else is going on okay these are the

characteristic signatures of these type of processes and there are six processes

these are sometimes known as winters formula these are ones that I’ve kind of

made up for the for the six here we got metabolic acidosis metabolic alkalosis

we’ve got acute respiratory acidosis chronic respiratory acidosis chronic

respiratory alkalosis and acute respiratory alkalosis and so those are

the rules great so I think the basic points here

were understood this is concludes part four we’re going to put everything to

come together and show you how to attack an acid-base problem and put it all

together through a systematic step in part five so please join me for part

five and we’ll kind of review everything there Thanks

the best video ever on acid base lecture.

u r an amazing teacher.greetings from china

First time its ever been that you explained something and I didn't quite get it.. : (

DR S. you are the best…I teach nursing and you have helped me understand this elusive subject so much better..thank you

informative…..THANK U !

dude……u saved me with this awesome lecture

yes, they represent what the body does all at the same time.

Hi, can you please explain how the maths work at the end of the video? I don't quite get the method :/

lol…. did anybody get the Risperdal commercial? killing 2 birds over here!

you make this look fun man

kinda motivated to be an internist now lol

who can tell me about the winters rules,where i found them,i want to read some article.I dont understand why in acidosis the HCO3 is down by 1 and the compensatory drops 1 by Pco2.WHy not HCO3 drops 2 and Pco2 by 3 ,this i want to understand.

Ugh… I didn't understand this…

i understand it but i dnt know whats the point of it

Amazingly clear !! Love these videos. Thank you so much.

You really are good doctor! Now I understand. Thank you!

Best explanation I've heard in regards to compensation. Thank you!

These are brilliant! thanks heaps!!!!

Help!!!! Can I find the lecture and notes to purchase under pulmonary??? I need to get my hands on the notes for this lecture soon please, I'm a nursing student and I have an exam soon.

great

Very rad lecture!

we cannot feeling the time how passe when we see your explication video

Thanks.

Thank you so much 🌸

Thanks for such a great explanation. I wonder as doctors we use our reasoning and creative mind to a minimum compared to majority of professions who use is to the maximum, what we mainly do is cramming. All we require is a good memory.

Hi Dr, i read that for every 1 meq/L fall in HCO3 the CO2 will decrease by 1.2 for metabolic acidosis and for every 1 meq/L rise in HCO3 the CO2 will increase by 0.7 for metabolic alkalosis. Is this correct?