abg-made-easy-1206968345600169-3

7/17/2019 abg-made-easy-1206968345600169-3

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Arterial Blood Gas

Analysis …..1

Dr Satish Deopujari

PediatricianHon. Prof. ( Pediatrics) JNMC

Chairman National

Intensive care chapter

Indian academ of pediatricsdeopujari!rediffmail.com

"isit us at#. http$%%rdso&.or'

No clic

mailto:[email protected]

mailto:[email protected]

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The Goal :

o provide *edside approach to

+*, analsis

No clic

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H ION CONC.

N.MOLS / L. pH

! "."!

#! ".$

%! ".%!

$! ".#!

&! ".H ION

OH ION

!

1%

pH stand for -poer of hdro'en-

H+ = 80 - last two digits of pH

Don/t clic ait #..till

0ast messa'e ##.. 1H 2 345last to di'its of pH6

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Bicarbonate:

Henderson ' Hassel(a)h e*+ation:

pH , p- Lo HC78

Dissolved C79

No clic

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Standard Bicarbonate:Plasma HCO

3

after equilibration

to a PaCO2 of 40 mm Hg

: Reflects non-resirator! acid base c"ange

: #o quantification of t"e e$tent of t"e

buffer base abnormalit!

Base %$cess:base to normalise HCO3 &to 24'

(it" PaCO2at 40 mm Hg

&Sigaard-)ndersen'

: Reflects metabolic art of acid base

: #o info* o+er t"at deri+ed from H,

CO2 and HCO3

: isinterreted in c"ronic or mi$ed

disorders

No clic

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Oxygenation

Indices:O2 Content of blood:Hb. x O2 Sat + Dissolved O2

(Don’t forget hemoglobin)

Oxygen Saturation: reported as ABG report( Derived from oxygen dis. curve

not a measured value )

Alveolar / arterial gradient:( seful ! to classify res"iratory failure )

No clic

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4 :4 94 84 ;4 <4 =4 >4 34 ?4 :44 Pa79

94

;4

=4

34

:44

@t. Shift

Normal arterio%venous difference

Shift of the curve ##chan'es saturation for a 'iven Pa79

Normal

No clic

7&'en delivered

to tissues

ith normall placed curve

Delivered o&'en

ith @t. Shift curve

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Al0eolar'arterial i22eren)eInspired O2 = 21 %

piO2 = (760-45) x . 21 = 150 mmHg

O2

CO2

palvO2 = piO2 3 pO2 ! "#

= 150 $ 40 ! 0.

= 150 $ 50 = 100 mm Hg

&aO2 = '0 mmHg

palvO2 3 parO2 = 10 mmHg7ne clic and ait

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Al0eolar' arterial i22eren)e

O2

CO2

Oxgenai*n ail,re I/ &

piO2 = 150

pO2 = 40

palvO2= 150 $ 40!.

=150-50

=100

&aO2 = 45

= 100 - 45 = 55

enilai*n ail,re 3O" &

piO2 = 150

pO2 = 0

palvO2= 150-0!.

=150-100

= 50

&aO2 = 45

= 50 - 45 = 5

P+79 (partial pres. of 79. in the alveolus.)

2 :<4 5 ( PaC79 % .3 )>=4 A ;< 2 >:< $ 9: B of >:< 2 :<4

No clic

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20 × 5 = 100

&pected Pa79 2

.iO2

× 5 = PaO2

Normal situation

No clic

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The Blood Gas Report:

normals…

pH 7.40 + 0.05

PaCO2 40 + 5 mm Hg

PaO2 0 ! "00 mm Hg

HCO#

24 + 4 mmol$%

O2 &at '(5

)l*as ment,on and see -O2

/"e essentials

HC78

No clic

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5

The

Steps forSuccessful

Blood Gas Analysis

No clic

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&tep 2/ho ,s respons,0le 1or th,s 2hange ,n pH 3 24lpr,t 56

CO2 *,ll hange pH ,n oppos,te d,ret,on

B,ar. *,ll hange pH ,n same d,ret,on

),dem,a: /,th HCO# 20 mmol$% 8 metaol,/,th PCO2 '45 mm hg 8 resp,rator

)l9alem,a: /,th HCO# '2 mmol$% 8 metaol,

/,th PCO2 #5 mm Hg 8 resp,rator

&tep "%oo9 at the pH

s the pat,ent a,dem, pH 7.#5

or al9alem, pH ' 7.45

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Step 3If there is a primary respiratory disturbance, is it

acute ?

.08 change in pH ( Acute )

.03 change in pH ( hronic )

!0 mm

hange

"a#$

%

No clic

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&tep 4.1 the d,st4r0an2e ,s meta0ol,2 ,s the resp,rator+

2ompensat,on appropr,ate6

-or metaol, a,dos,s:

;peted PaCO2 8 3".5 ; <HCO#= + + 2

or s,mpl…

e;peted PaCO2 8 last t*o d,g,ts o1 pH

-or metaol, al9alos,s:

;peted PaCO2 8 > mm 1or "0 m?. r,se ,n B,ar.

&spet ,1 ............. atal PaCO2 ,s more than e;peted : add,t,onal …

resp,rator a,dos,s

atal PaCO2 ,s less than e;peted : add,t,onal …

resp,rator al9alos,s

No clic

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&tep 4 ont..1 there ,s meta0ol,2 a2,dos,s@ ,s there a *,de an,on gap 6

Aa ! 3Cl!+ HCO#

! 8 )n,on Gap sall "2

1 '"2@ )n,on Gap ),dos,s : ethanol

rem,a

D ,aet, Eetoa,dos,s

P araldehde

n1et,on 3lat, a,d thlene Glol

& al,late

Common ped,atr, ases

" %at, a,dos,s

2 etaol, d,sorders# Renal 1a,lre

No clic

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t" ste

Clinical correlation5

No clic

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HCO#M4TA.pH

5aCO pH 64S5.

Sa7e dire)tion

Opposite dire)tion

Sa7e dire)tion

No clic

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@ememer the format

pH

PaC79

Pa79

No clic

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Primar lesionPrimar lesion

Compensation

pH

*icaronate

PaC79

M+*70IC +CID7SIS

HEP@ "NI0+I7N

*IC+@* CH+N,S

pH in same direction

Lo8

Al9ali

hree clics

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Primar lesion

Compensation

pH

*icaronate

PaC79

M+*70IC +0F+07SIS

HEP7 "NI0+I7N

*IC+@* CH+N,S

pH in same direction

Hih

Al9ali

hree clics

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Primar lesion

compensation

pH

PaC7 9

*IC+@*

@espirator acidosis

C7 9 CH+N,S

pH in opposite direction

Hi'h

C79

hree clics

Gait for red circle

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Primar lesionPrimar lesion

compensation

pH

PaC7 9

*IC+@*

@espirator alalosis

PaC7 9 CH+N,S

pH in opposite direction

0o

PaC79

hree clics

Gait for red circle

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PaCO of 10 H

Acute change .08

Chronic change .03

No clic

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INT46564TATION O A.B.G.

O;6 ST45 M4THO O 4OSAT

1< LOO- O6 pH

< =HO IS TH4 C;L56IT >

#< I 64S5I6ATO6? AC;T4 / CH6ONIC >

%< I M4TABOLIC / COM5. / ANION GA5

CLINICAL CO664LATION

No clic

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c

om p

en s

a t i o

n

considered

completehen the

pH returnsto

normalrange

Clinical lood 'ases Malle

No clic

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C

7MP N

S I 7N

0

I MI ) S

M4TABLIC ACIOSIS

5aCO , ;p to 1! >

M4TABOLIC AL-ALOSIS

5aCO , Ma@i7+7 &O

64S5I6ATO6? ACIOSIS

BICA6B , Ma@i7+7 %!

64S5I6ATO6? AL-ALOSIS

BICA6B , ;p to 1!

No clic

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Blood Gas 6eport

Meas+red #".!o

C

pH >.<98

PaC79 84.: mm H'

Pa79 :4<.8 mm H'

Cal)+lated ata

HC78 act 99 mmol % 0

79 Sat ?3.8 B

P79(+ 5 a) 3 mm H'

P79 (a % +) 4.?8

4ntered ata

i79 9:.4 B

Case

1 !ear old female (it"

sudden onset of d!snea*

#o Coug" or C"est Pain

itals normal but RR 1,

an$ious*

7ne clic for anser

+cute respirator alalosis

+nd h acute

i li

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Case 2 1 !ear old male (it" rogressi+e resirator! distress

uscular d!stro"! *

Blood Gas 6eport

Meas+red #".!o

C

pH >.84:

PaC79 >=.9 mm H'

Pa79 ;<.< mm H'

Cal)+lated ata

HC78 act 8<.: mmol % 0

79 Sat >3 B

P79 (+ 5 a) ?.< mm H'

P79 (a % +) 4.38

4ntered ata

i79 9: B

pH 7.5 8a9idemia

"es. 9idemia 8 Hig: &aO2 and l*; pH

Hp*xemia

3*rmal -a gradien

O2 =76-40=6

/xpe9ed pH <*r ( 9,e ) = .0 <*r 10

/xpe9ed ( 9,e ) pH = 7.40 - 0.2'=7.11

:r*ni9 resp. a9id*sis

Hpoventilation

Chronic respirator acidosis

Gith hpo&ia due to hpoventilation

ive clics

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7.60 20 7.50 30

7.4040

7.3050

7.2060

7.1070

HPaCO2

+cute respirator chan'e

No clic

%ast t*o d,g,ts

pH34 A PaC79

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Case 3-!ear-old male ast"matic5

3 da!s of coug", d!snea

and ort"onea not

resonding to usual

bronc"odilators*

O6%: Resirator! distress5

surasternal and

intercostal retraction5tired loo7ing5 on 4 8 #C*

Blood Gas 6eport

Meas+red #".!o

C

pH >. 9;

PaC79 ;?.: mm H'

Pa79 ==.8 mm H'

Cal)+lated ataHC78 act :3.4 mmol % 0

79 Sat ?9 B

P79 (+ 5 a) mm H'

P79 (a % +)

4ntered ata

i79 84 B

15-66= 7

pH 7.5 a9idemia

&aO2 >45 respira*r a9idemia

piO2 = 715x.=214.5 ! palvO2 = 214-4'!.=15 ide ! a gradien

Hp*xia

I?H I3"/@/ I3 O2 AI"A B@? "I@/ C

Ai9arD*nae is l*;EEE

eaD*li9 a9id*sis + respira*r a9id*sis

84 < 2 :<4

O2 = 4' - 40 = '

/xpe9ed pH ( 9,e ) = '!10 x 0.0 = 0.072

/xpe9ed pH ( 9,e ) = 7.40 - 0.072 = 7.2

9,e resp. a9id*sis

'year'old 7ale asth7ati) 8ith resp. distress Si& clics

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Case 4 !ear old diabetic (it" resi* distress fatigue and loss of aetite*

Blood Gas 6eport

Meas+red #".!o

C

pH >.98

PaC79 98 mm H'

Pa79 ::4.< mm H'

Cal)+lated ataHC78 act :; mmol % 0

79 Sat B

P79 (+ 5 a) mm H'

P79 (a % +)

4ntered atai79 9:.4 B

pH 7.5 a9idemia

HO 22 meaD*li9 a9idemia

as ;* digis *< pH

*rresp*nd ;i: 9*2

I< 3a = 10F

l = '0

ni*n ap = 10 - ('0 + 14)

= 10 $ 104 = 26

hree clics

C

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Blood Gas 6eport

Meas+red #".!o

C

pH >.;=

PaC79 93.: mm H'

Pa79 <<.8 mm H'

Cal)+lated ataHC78 act :?.9 mmol % 0

79 Sat B

P79 (+ 5 a) mm H'

P79 (a % +)

4ntered atai79 9;.4 B

Case : 0 !ear old c"ild (it" ence"alitis

pH almost ithin normal ran'e

Mild alalosis

PaC79 is lo K respirator

lo around :4

( +cute ) .43

(Chronic ) .48

BC)RBA)TR)

*icar loos lo

Is it e&pected

our clics

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hese findin's are most consistent ith#.

a) Metaolic acidosis ith compensator Hpocapnia.

) Primar metaolic acidosis ithrespirator alalosis.

c) +cute respirator alalosis full compensated.

d) Chronic respirator alalosis full compensated.

pH >.8?

PC79 l<mmH'

HC78 3mmol%0Pa79 ?4 mmH'

or 7eta(oli) a)idosis: ;LL COM54NSATION

4@pe)ted 5aCO , 1.$ @ HCO#D< <

=interEs e*+ation<

5CO ……SHO;L B4 !

Case =####.

7ne clic

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+dolescent o ith appendicitis K posted for sur'er K he is a non

case of S0.

His pre5op +*, shos

$ @oom airpH >.8?

pC79 l<mmH'

pa79 ?4 mmH'

HC78 3mmol%0

hese findin's are most consistent ith#.

a) Metaolic acidosis ith compensator Hpocapnia.

) Primar metaolic acidosis ith respirator alalosis.

c) +cute respirator alalosis full compensated.

d) Chronic respirator alalosis full compensated.

Ghat is the proale cause for the aove findin's +re the 7F

as far as o&'enation is concerned

Case "……….

No clic

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Patient as hpo volumic K received Normal Saline olus...

Corrected acidosisHe as operated #.ut post5op ecame dros

His +*,##..

i79#.84B

pH >.83

PaC79 83

Pa79 =4

:) Gh hpo&emia

9) Gere the lun's ad to e'in ith ( Pre 7P 5aO F! 77H <

8) Micro atelectesis durin' sur'er +nesthetist 'oofed up the case

;) Pure and simple hpoventilation #..Sedation

No clic

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Gh hpo&emia

0un's ere ad to e'in ith

Micro atelectesis durin' sur'erPure and simple hpoventilation sedation

P@ 7P #.+*, on room air

pH >.8?PaC79 l<mmH'

Pa79 ?4 mmH'

HC78 3mmol%0

5re O5 .....A/a radientp

al0O

, 5

iO

3 5aCO

/ 6

, 1$! 3 1$ / !.

, 1$! 3 1 , 1# 77 H

1# 3 F!, % =I4 A / a radient

7&'enation status 'ood #..

7ne clic

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+pparentl the lun's looed 'ood ith Pa79 of ?4##.

*ut have a 'ood loo at the +*, a'ain

Gith ash out of C7 9 ###.

he e&pected Pa79 should have een more than ?4 .

his coupled ith correction of acidosis

( normaliLin' PaC79 )

0oered the Pa79 #post operativel.Conclusion ##..

0un's ere not normal to e'in ith ( S0 )##..

No clic

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Correlate Pa79 ith i79

*ut please also correlate ith PaC79

0earnin' point

No clic

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@espirator

+lalosisIs it acute

Ghat is the

Dia'nosis

Clic for anser

Case 3KKKKKKKKKKKKKKKKKK

pH >.<38

PC79 :?.3HC78 :3.>

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H+NFS

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