8-step guide to abg analysis_ tic-tac-toe method - nurseslabs

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8-Step Guide to ABG Analysis: Tic-Tac-ToeMethodTheeasiestmethodtointerpretABGs!

ByGilWayne,RN Jan21,2015



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An arterial blood gas (ABG) is a blood test that measures the acidity (pH) and the levels of oxygenand carbon dioxide in the blood. Blood for an ABG test is taken from an artery whereas most otherblood tests are done on a sample of blood taken from a vein. This test is done to monitor severalconditions that can cause serious health complications especially to critically ill individuals.

Every day, a lot of nursing and medical students assigned in acute areas encounter ABG results,which they may not necessarily be able to interpret with its knotty aspect. They struggle over theinterpretation of its measurements, but they are not especially complicated nor difficult if youunderstand the basic physiology and have a step by step process to analyze and interpret them.



There may be various tips and strategies to guide you, from mnemonics, to charts, to lectures, topractice, but this article will tell you how to interpret ABGs in the easiest possible way. And once youhave finished reading this, youll be doing actual ABG analysis in the NCLEX with fun and excitement!Here are the steps:

1.Knowthenormalvalues

Know the normal and abnormal ABG values when you review the lab reports. Theyre fairly easy toremember: for pH, the normal value is 7.35 to 7.45; 35-45 for paCO and 22-26 for HCO . Rememberalso this diagram and note that paCO is really inverted for the purpose of this method.

2.DetermineifpHisunderacidosisoralkalosis

Next thing to do is to determine the acidity or alkalinity of the blood through the value of pH. The pHlevel of a healthy human should be between 7.35 to 7.45. The human body is constantly striving tokeep pH in balance.

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pH level below 7.35 is acidosis pH level above 7.45 is alkalosis

3.Determineifacidbaseisrespiratoryormetabolic

Next thing you need to determine is whether the acid base is Respiratory or Metabolic.

paCO = Respiratory HCO = Metabolic

4.RememberROME

Still, it all boils down to mnemonics. The mnemonic RO-ME.

Respiratory Opposite

When pH is up, PaCO is down = Alkalosis When pH is down, PaCO is up = Acidosis

Metabolic Equal

When pH is up, HCO is up = Alkalosis When pH is down, HCO is down = Acidosis

5.TicTacToe

And yes, ABG problems can be solved work using the tic-tac-toe method. All you have to do is make ablank chartsimilar to this:

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6.MarktheChart

Using the lab result values, mark them on your tic-tac-toe. Lets begin with this sample problem:

pH: 7.26, paCO : 32, HCO : 18

Using the normal values reference chart in the first step, determine where the values should beunder in the tic-tac-toe. In the given example, the solution is as follows:

pH of 7.26 is LOW = ACID so place pH under Acid paCO of 32 is LOW = BASE so place paCO under Base HCO of 18 is LOW = ACID so place HCO under Acid

Your chart should looklike this:

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7.Matchitup

In this step, determineat which column matches up with the pH. In the given example, HCO goeswith pH. HCO is considered Metabolic (shown in step 3), and both are under Acid, so this exampleimplies Metabolic Acidosis.

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8.Determinecompensation

The last step is to determine if the ABG is Compensated, Partially Compensated, or Uncompensated.Heres the trick:

If pH is NORMAL, PaCO and HCO are both ABNORMAL = Compensated If pH is ABNORMAL, PaCO and HCO are both ABNORMAL = Partially Compensated If pH is ABNORMAL, PaCO or HCO is ABNORMAL = Uncompensated

Therefore this ABG is METABOLIC ACIDOSIS, PARTIALLY COMPENSATED .

By applying the steps above, interpret the following ABGs:

pH:7.44, PaCO : 30, HCO :21

pH is NORMAL = NORMAL so place pH under Normal

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PaCO is LOW = BASE so place PaCO under Base HCO is LOW = ACID so place HCO under Acid

*Since the acidity of the blood is determined by the value of the pH, determine whether the normalpH is SLIGHTLY ACIDIC or SLIGHTLY BASIC. In this example, pH is NORMAL but SLIGHTLY BASICtherefore it is ALKALOSIS.

In this case PaCO goes with pH. PaCO is considered Respiratory (shown in step 3), and both areunder Basic, so this example implies Respiratory Alkalosis. The HCO is also abnormal. When pH isNORMAL and PaCO and HCO are both ABNORMAL, it indicates FULL COMPENSATION.

Therefore this ABG is RESPIRATORY ALKALOSIS, FULLY COMPENSATED.

Try this problem next:

pH 7.1, PaCO 40, HCO 18

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pH is LOW = ACID so place pH under Acid PaCO is NORMAL = NORMAL so place PaCO under Normal HCO is LOW = ACID so place HCO under Acid

In this case HCO goes with pH. HCO is considered Metabolic (shown in step 3), and both are underAcidic, so this example implies Metabolic Acidosis. The PaCO is normal. When pH is ABNORMAL, andwhen either one of PaCO or HCO is ABNORMAL, it indicates UNCOMPENSATION.

Therefore this ABG is METABOLIC ACIDOSIS, UNCOMPENSATED.

Tryitoutwiththesequizzes

Want to try out the Tic-Tac-Toe method? Here are some sample ABG Analysis quizzes:

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ABG Analysis NCLEX Exam 1 (10 Items)ABG Analysis NCLEX Exam 2 (10 Items)ABG Analysis NCLEX Exam 3 (10 Items)

GilWayne,RNhttp://nurseslabs.com

GilWayneisaregisterednurseandacontributoratNurseslabs.com.Preferswriting,travelinganddiscoveringstuffs.Notafanofworkinginahospital,butenjoysexploringnursingoutsideitswalls!Ilikethecolorgray,butcantimaginemyselfin

grayscrubs...lol!

8-step guide to abg analysis_ tic-tac-toe method - nurseslabs

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