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:Moderator Dr PujaSingh :Speaker Dr Sakshi

Gupta

ARTERIARTERIABLOODBLOODGASESASES

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DEFINITIONBlood gas analysis, also called arterial blood gas (ABG)

analysis, is a test which measures the amounts ofoxygen and carbon dioxide in the blood, as well asthe acidity (pH) of the blood.

It involves puncturing an artery with a thin needle and

syringe and drawing a small volume of blood. Common sites:

Radial A Femoral A

Brachial A Dorsalis Pedis A

Axillary A

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&OBJECTIVES USES

Understand Ventilation and PerfusionMechanics

Aids in ventilator management /Improvement in acid base management allows

for optimal function of medications

Aids in establishing a diagnosis Helps guide treatment plan /Acid base status may alter electrolyte

/levels critical to patient status care Recognize Signs & Symptoms of Respiratory

Failure Analyze and Interpret Acid Base Disturbances

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Before beginning

Allen s test for radial and

ulnar artery Common errors of arterial blood

sampling :Air in sample PCO2, ,pH PO2

:Venous mixture PCO2, ,pHPO2

(Excess anticoagulant dilutionPCO2, ,pH PO2

, ,The plastic disposable syringeprefilledwith a small amount

of an appropriate type oflyophilized heparin salt is

.used

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Before beginning ollect blood gas specimens inlass syringes and ice theseamples immediately low down the metabolic rate ofhe leukocytes inimize the reduction in oxygenlevels

rterial line collection requireshat an appropriate volume beithdrawn initially to assurehat the line contains onlyncontaminated arterial bloodefore the actual sample iscollected :oc al a n e s t h e s i a t o m a k e t her te r i a l p u n c tu re e as i e r t oa c c o m p l i s h eparin is the anticoagulant ofhoice for the measurement of.as analytes

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- . -pH 7 35.7 45

PaCO2 - -35 45mmHg

PaO 2 - -80 100mmHg

HCO3 -24 + 4mmol/L %MetHb .pH 7 45

= . If pH 7 4 NormalMixed or Fully compensated

tep 2tep 2

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.tep 3 .tep 3CULPRIT?ULPRIT?HCO3METABOLIC

> .. .26 Met Alkalosis

< .22 Met Acidosis

PCO2 RESPIRATORY> .45 Resp Acidosis

HCO3 =Base

-Normal 22

26

CO2 =ACID

-Normal 3545

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If there is a primary Respiratory,disturbance

is it acute ?

. ( )08 change in pH Acute

. ( )03 change in pH Chronic

10 mmChange

PaCO2

=

Remember relation of CO2 and pH

ep 4 ep 4

p 4 continuedp 4 continued

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7.60207.5030

7.4040

7.3050

7.2060

7.1070pHaCO2

cute respiratory change

pH ast two digits 80 PaCO2

p 4 continuedp 4 continued

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IRATORY disorders

cted HCO3for a Change in CO2 ......... 1 2 3 4

.Acidosis ( )expected HCO3= .0 1 x CO

2

.Alkalosis ( )expected HCO3= .0 2 x CO2

.Acidosis ( )expected HCO3

= .0 35 x CO2

.Alkaosis

( )expected HCO

3

ute respiratory

ronic respiratory

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If it is a primary Metabolic

,disturbancewhether respiratory compensationappropriate?

:For metabolic acidosisExpected PCO2 = ( . [ 1 5 x HCO 3]) +8 +2

( )Winter s equation

:For metabolic alkalosis

= ( . ) + Expected PCO2 0 7 x HCO3 212UNCERTAIN COMPENSATION

CO2is equal to

Last two digitsof pH

:Remember If .............Suspect actual PaCO2is more than expected

...additional respiratoryacidosis

actual PaCO2 is less than expected...additional respiratory

alkalosis

tep 5tep 5

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If metabolic acidosis is there

How is anion gap? ...Is it wide- (Na Cl-+ HCO3

-) = , :If 12 Anion Gap AcidosisMethanolUremiaDiabetic KetoacidosisP

araldehydeI ( )nfection lactic acidE thylene GlycolS alicylate

ommon pediatric causes

Lactic acidosisMetabolic disorders

Renal failure

ep 5ep 5 .ont.ont

Mixed Acid BaseMixed Acid Base

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Mixed Acid-BaseMixed Acid-BaseDisorders : CluesDisorders : Clues

-- Clinical history-- ,pH normal abnormal PCO2n HCO3

-- PCO2n HCO3 moving oppositedirections-- Degree of compensation for primary

disorder is inappropriate-- Find Delta Gap

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h steph step

linical correlationlinical correlation7

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Thank you