ABG for Dummies

Working in Emergency department require you to capable do most of the procedure include reading Arterial Blood Gases Value.

Got problem with it?

Here, I will explain in a very easy way..My way..LOL..

First, to detect the abnormalities,we must knew the normal value.

Blood PH ------>7.35 - 7.45        

PaCO2----------> 35 - 45 ( mmHg )

HCO3 ---------->22-26 mEq / L

PaO2------------>80 - 100 mmHg

SaO2 ------------>95% -100%

BE -------------> -2  to +2

explanation:

PH, PaCo2, and HCo3 tell us about acid base balance

SaO2 and PaO2 indicates oxygenation status.

BE Indicates the amount of excess or insufficient level of sod.Bicab in the system.

Important in calculation of Dose Sodium Bicab Need to be given.

PH

If less than 7.35 its acidic and more than 7.45 is alkali .

PaCo2 

Less than 35 - alkali

More than 45 - acidic

HCo3

The calculated value of amount sodium bicabarbonat in blood stream.

Less than 22 - acidic

More than 26 - alkali

BEFORE WE PROCEED, BEAR IN MIND :

Co2 ---->  Lung ( Respiratory) problem

HCo3 ----> Kidney (metabolic ) problem

ANALYZING ABG

STEP 1 - PH  acidic or alkali ?

STEP 2 -Co2  acidic or alkali ?

STEP 3 - HCo3 acidic or alkali?

e.g

PH        7.48  ------->  alkali
Co2       48 ----------> acidic
HCo3    28 ----------> alkali

Well, Seems like alkali wins right? Which system got prob? Kidney the winner right?

So, its Metabolic Alkalosis

Okay, How if the PH is normal ?? It could happen...

e.g

PH        7.38  ------->  Normal
Co2       48 ----------> acidic
HCo3    28 ----------> alkali

Alright, here we look at the normal range of the blood PH.

Its 7.35 to 7.45

Just take single value in between of that two value -----> its 7.4

So, everything give you below than 7.4 consider as acidic and above 7.4 is consider alkali.

Problem solve?

So, try intepret the ABG value above.....what is it?

Answer : 

PH        7.38  ------->  Normal ( more to acidic )
Co2       48 ----------> acidic
HCo3    28 ----------> alkali

So its Respiratory Acidosis  

wink* wink*

Now we have to know whether the compensation between kidney and lungs did happen or not.

How do we know??

Well I make it Easy for you..

There is three type of compensation

1. Fully compensated
2. Partially Compensated
3. No Compensation

FULLY COMPENSATED

In this condition, both lung and kidney do their job well..so,the BLOOD PH will maintained in NORMAL range.KIDNEY and LUNG exhausted because working hard.So,their value both out of normal range in opposite way ( means, if kidney alkali lung will be acidic and vice versa)...because they give and take.

PARTIALLY COMPENSATION

Well in this situation, Kidney and lung do their best but still cannot maintain the PH in normal Value. After trying so hard,their stopped.Three of them all in bad shape.All out of normal range..

NO COMPENSATION

In this situation, Blood PH is out of normal range.

Here got two situation :

1.  Kidney or lung still in normal value. One of them in bad shape though...LOL
   its like this : kidney abnormal and lung normal or vice versa.
2. Or both of them goes in same way...both acidic or both alkali.

HERE :

e.g

PH        7.48  ------->  alkali
Co2       48 ----------> acidic
HCo3    28 ----------> alkali

 metabolic alkolosis, partially compensanted

Thank You.. :)