# Medical Acid Base and ABGs Explained Clearly by MedCram.com | 5 of 8

welcome to part 5 of Medical

acid-base this is where we want to kind of put everything together into one

complete package here and and then maybe do some questions here and some later

things let’s let’s kind of go back here and review remember we talked about

bicarbonate and the different types of bicarb waves of loss remember we said

one way of losing bicarb is if you combined it with a proton and that was

special because if you did you would have leave behind a conjugate acid or

conjugate base of that acid which is negatively charged and that would leave

you with a increased anion gap and that anion gap would for sure tell you that

you had some sort of a metabolic process going on the other way to lose

bicarbonate again is just simply losing it and you can do that that’s just a

simple metabolic acidosis so the first thing that you really need to do when

you’re doing this is to and we’ll get rid of all this here is to the first

rule whenever you want to do an acid-base problem and you can take this

to the bank is you need to calculate the anion gap anion gap remember how to do

that it is remember what the the anion gap is always the sodium minus the

chloride plus the bicarb and that should equal the anion gap so when you’ve

calculated the anion gap you need to figure out if it’s elevated and assuming

that the albumin is for it we’ll just assume that the albumin is for for this

discussion if the anion gap is greater than 12 if the anion gap is greater than

12 let’s just say for argument’s sake that the anion gap that we calculate is

20 that means we take the ni gap so anion gap minus 12

is going to give us something we call the Delta gap in that case it’s equal to

in this case it would be equal to 8 what does that mean what is a delta gap that

simply means there are 8 units of conjugate base negatively charged

particles out there more than there should be ok so what does that mean

again we got bicarb and we’ve got a acid with a proton attached to it and what

happened was eight of these released their protons bound with the bicarb and

that went off to form h2o plus CO 2 plus conjugate base negatively charged and

that’s then those eight of those is what we’re picking up here so if that’s the

case if our ni gap is 20 and that’s 8 more than it should be at 12 that means

we have anti Delta gap of 8 if that’s the case how many bicarbonate molecules

should we have lost we should have lost 8 the same amount

this tells us this Delta gap tells us how many bicarbonate molecules we should

have lost now let’s say we started off with 24 bicarbonate molecules that’s

normal if we calculate out a delta gap of 8 what should our new bicarbonate

level be it should be 16 it should have dropped so we had 24 bicarbonate

starting off and then we developed an anion gap metabolic acidosis and we

calculate our Delta gap to be 8 that means we took our anti gap which is 20

we subtracted out the normal anion gap that we should always be having which is

12 and we found that we were eight more than normal the body has to deal with

those eight more and the way it deals with that is by combining with bicarb so

if there’s eight things to deal with that means we should have lost eight

molecules of bicarb when we were gone from 24 down to 16 that’s what it should

have been another way of looking at this is saying that if we take our current

bicarbonate level and we add to it the Delta gap we should get back to 24 what

happens though if we do that and we end up with something like 16 or 17 then

what that means is that there must be another process that is causing us to

lose bicarbonate or let’s say we we do this calculation we take our current

bicarbonate level and we add our Delta gap to it and we come up with something

that’s greater than 24 let’s say it’s 30 that must mean that there’s another

process another metabolic process that’s occurring that’s causing us to gain

bicarbonate the reason why this is important is because we can tell if

multiple different metabolic processes are occurring at the same time so what I

want you to do on all these acid-base questions is calculate the anion gap

always do that and when you do that you simply subtract 12 from it assuming that

you have a normal albumin and you’ll get the Delta gap now that Delta gap tells

you specifically one thing or two things specifically if you have a delta gap

number one you can take it to the bank that you’ve got a anion gap metabolic

process there is only one thing that causes an anion gap and that is an anion

gap metabolic acidosis period so number one you already know if you’re n on gap

is greater than 12 and therefore you have a delta gap that’s positive that

you have an anion gap metabolic acidosis what you don’t know is if you have a non

anion gap metabolic acidosis that’s occurring what’s a non anion gap

metabolic acidosis it’s simply a process where you just lose bicarbonate or you

could have a a metabolic alkalosis that’s a process where you’re gaining

bicarbonate like vomiting or something like that how are you going to know if

that’s the case it’s very simple you simply take the gap the Delta gap I

should say you add it to your current bike

urban at level and if you got a number that’s abnormally high that must mean

you have an additional metabolic alkalosis occurring if you get a number

that’s low less than twenty two or twenty that means you have a non anion

gap metabolic acidosis that’s occurring simply meaning that you’re losing

bicarbonate through some other process something like diarrhea or something

where you’re not forming a conjugate base so getting back number one

calculate the anion gap and if there is a gap calculate the Delta gap okay if you do have an anti gap you’d by

definition have an anti gap metabolic acidosis then calculate the Delta gap

take the Delta gap and add to that the current bicarb okay if it is less than

22 as we’ve said before there are normals for our bicarbonates

and if it’s less than 22 then you must have a non anion gap metabolic acidosis okay if it however is greater than 26

then you have a metabolic alkalosis because you’ve basically factored in

this Delta gap and if you find that your bicarb is still high there must be

another process occurring and here when you factor in your Delta gap to your

current bicarb if it’s still low there must be in another metabolic acidosis

problem occurring the next thing to do is to look at your pH and your P co2 so

look at the pH and the pco2 if they’re going in the same direction then it’s

metabolic and I’m sure you can tell whether it’s an acidosis or an alkalosis

just look at the pH and tell if it’s going in different directions then it

must be our respiratory okay and then finally number four is apply winters

formula and I say that because if you apply

winters formula and the pco2 or the P the pco2 is either too high or too low

then there must be an additional respiratory process and we’ll go through

these the best way to do this is actually go through the questions and

see what they show so that’s the next step is to go through the questions but

before I do that I want to give you some examples about what things can cause

respiratory acidosis and metabolic acidosis etc and so let me go ahead and

do that now for you so again if we go to our graph that we had remember you had pco2 on the y-axis and

ph here on the X here we had metabolic acidosis now there’s two types of

metabolic acidosis there’s a mine gap and there’s non anion gap metabolic

acidosis these are the two processes that are occurring now anion gap you

should think about as mud piles em you D P I l II s and that’s the mnemonic these

are all the things that can cause an anion gap metabolic acidosis M stands

for methanol okay methanol is metabolized into formic acid formic acid

gives off a proton that proton is melded with the bicarbonate leaving formate in

this case the formate is causing the anion gap u stands for uremia uremia in

kidney failure there’s all sorts of acids and conjugate bases that can build

up there sulfates phosphates etc d stands for d ka diabetic ketoacidosis

but in fact all sorts of ketone ketone bodies can form anion gap and remember

you can get ketone bodies and diabetes diabetic ketoacidosis you can get

starvation ketosis you can even get alcoholic ketosis P is kind of a

placeholder paraldehyde can cause it i stands for iron isoniazid or i NH L

stands for lactic acidosis so you can get lactic acidosis in septicemia lactic

acidosis in ischemia and the lactic acid gives off the proton again it gets

buffered by the bicarbonate leaving lactate lactate is not in our chem 7

therefore causes an ni gap ye stands for ethylene glycol also alcohol so the metabolism of those

products can lead to negative anions which are not accounted for in the chem

7 that caused the anion gap and then s is salicylates salicylate it’s like

aspirin incidentally that can also cause an acute respiratory alkalosis and so

whenever you have an anion gap you got to think about the mud piles as the

reason for non Anna get metabolic acidosis just remember you’re not

getting the situation where bicarb is being lost because of its combining with

a proton with a conjugate base here you’re losing bicarb because you’re just

losing bicarb it’s not combining with anything you’re

just losing it the biggest thing here that you would need to know is diarrhea okay diarrhea also something called

renal tubular acidosis especially type 1 and the other thing here that can cause

a metabolic acidosis is carbonic anhydrase inhibitors or CA this would be

like medications that block bicarbonate reabsorption in the in the proximal

convoluted tubule as soon as Olamide is an example of a

carbonic anhydrase inhibitor and it causes diuresis which is bicarbonate

rich the other thing that can also cause this is Addison’s disease okay but

Addison’s disease is kind of in it is placed by itself these three here can

cause hypokalemia Addison’s can cause hyperkalemia so these three here would

actually be considered a hypokalemic hyperchloremia we would call it our high

chloride metabolic acidosis whereas Addison’s disease this is where

you have adrenal insufficiency would cause a hyperkalemic metabolic acidosis

and remember I don’t want to get into too much detail but if you lose the

function of the adrenal gland you can you don’t get aldosterone which is

secreted from the zona glomerulosa and that doesn’t work well the distal

convoluted tubules and when that’s not working you’re not getting potassium and

proton excretion and therefore you’re you’re losing bicarbonate because it has

to buffer that that proton there so anyway that’s a non Ana got metabolic

acidosis so what can cause a metabolic alkalosis metabolic alkalosis can be

caused by vomiting okay so you’re losing chloride and the other thing that can

cause a metabolic alkalosis that you should remember here is added as

actually Cushing’s disease so too much adrenal cortical hormones the difference

between these two however is that vomiting will respond to saline or

sodium chloride and that’s known as chloride responsive

whereas Cushing’s where you have too much adrenal is chloride insensitive so

it won’t respond to sodium chloride in terms of the respiratory components

these are set these are pretty obvious so what could cause a an acute

respiratory acidosis Q respiratory acidosis would be something like a COPD

exacerbation okay so something that happens acutely or too much drugs

narcotics so basically the lungs stop working pretty quickly and there’s no

chance for the kidney to compensate what we call is a chronic respiratory

acidosis just compensated COPD we see this all the time how do you know for

patients with chronic co2 retainer when they come in what we know they got high

bicarb that means their kidneys had a long time to compensate for that high

co2 they still have an acidosis though so what could cause an acute respiratory

alkalosis hyperventilation anxiety disorder asthma exacerbation can also do

it in the early stages asthma and then what about in the chronic chronic

respiratory alkalosis so when breathing fast for a long time

the one that that’s probably the most common is actually pregnancy so in

pregnancy of progesterone progesterone is a respiratory stimulant and that

people could be breathing fast for time and that would cause that type of a

picture so here are the examples I think in the next section we’re going to go

actually over questions and we’re gonna go in the order that we talked about and

we’ll come up with blood gases and chem 7 s and figure out exactly what is going

on with the patient and and I think if we go through things step by step you’ll

start to understand why we’re doing things the way we are so join me for

part six thanks

in coming times this wud be the most sought out lectures…!!

keep up the good work sir…!!

Great work, logical explaination of a tough object

great and easy to understand explaination. Thanks a lot Dr. Roger for making things simple

awesome dr! awesome!

8:48 – what if anion gap + current HCO3 is between 24 and 26??

22 and 26… sorry

if you mean what if the delta gap and bicarb added is between 22 and 26? Then the answer is that there is no other metabolic acid base problem going on or, if there is, then it is a non anion gap metabolic acidosis and a metabolic alkalosis of equal magnitude canceling each other out as far as bicarb is concerned.

I think you meant loss of bicarb in Type 2 RTA

Excellent video set- well explained- thanks for taking the time.

you are awesom sir

.,

God bless u dr 🙂

You r awesome sir …thank u soo much …….

very nice lecture. Could you please cover potassium disturbances too?

Two people accidentally hit the thumbs down button.

Wonderful series of videos!

"If you have a delta gap, number one, you can take it to the bank that you've got a anion gap metabolic process.

There is only one thing that causes an anion gap, and that is an anion gap metabolic acidosis, period."

Should it be, "There is only one thing that causes a delta gap, and that is an anion gap metabolic acidosis, period?"

I believe the anion gap caused by albumin is normal, right?

Thank you !!!

The two types of metabolic acidosis should be "delta gap metabolic acidosis" and "non-delta gap metabolic acidosis". The delta gap defines them, not the anion gap!

MED~ Cram..( i heard CRAB all the time)~ … always got me 😀 thank you so much for all the videos!!!!

Did you mean Conn's Syndrome (primary hyperaldosteronism) causes metabolic alkalosis vs. Cushing's Disease ( Pituitary adenoma = release of excess ACTH)?

Or does increased ACTH also affect aldosterone production?

Super! thank you.

thank you the video was really useful

skinny the time how pass when we see your lecture harry potter version lol

Thanks.

super great! Thank you

This is fantastic. You've certainly simplified it