03. Respiratory Physiology

8/18/2019 03. Respiratory Physiology

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RESPIRATORYPHYSIOLOGY

Dr. Arif santoso, Sp.P, Ph.D, FAPSR


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Lecture Outline

Basics of the Respiratory SystemFunctions & functional anatomy

Gas Laws

Ventilation Diffusion & Soluility Gas !"chan#e

Lun#s$issues

Gas $ransport in Bloo% Re#ulation of Ventilation & mpacts on

Gas le'els, p(


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Basics of the RespiratorySystem

General Functions !"chan#e of #ases

) Directionality %epen%s on #ra%ients*

Atmosphere to loo%

Bloo% to tissues Re#ulation of p(

Depen%ent on rate of +- release

Protection Vocaliation Synthesis


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Respiration /hat is respiration0

Respiration 1 the series of e"chan#es thatlea%s to the upta2e of o"y#en y the cells, an%the release of caron %io"i%e to the lun#s

Step 3 1 'entilation nspiration & e"piration

Step - 1 e"chan#e etween al'eoli 4lun#s5 an%

pulmonary capillaries 4loo%5Referre% to as External Respiration

Step 6 1 transport of #ases in loo%Step 7 1 e"chan#e etween loo% an% cells

Referre% to as Internal Respiration

Cellular respiration 1 use of o"y#en in A$Psynthesis


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External Respiration

Internal Respiration

Schematic View of Respiration


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Functional Anatomy /hat structural aspects must e consi%ere% in theprocess of respiration0$he con%uction portion$he e"chan#e portion$he structures in'ol'e% with

'entilation) S2eletal & musculature) Pleural memranes) 8eural pathways

All %i'i%e% into

9pper respiratory tract) !ntrance to laryn"Lower respiratory tract

) Laryn" to al'eoli 4tracheato lun#s5


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Functional Anatomy Bones, :uscles & :emranes


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Functional Anatomy Function of these Bones, :uscles &:emranes+reate an% transmit a pressure #ra%ient

) Relyin# onthe attachments of the

muscles to the ris4an% o'erlyin# tissues5$he attachment of the

%iaphra#m to the aseof the lun#s an% associate%pleural memranes

$he cohesion of the parietalpleural memrane to the

'isceral pleural memrane!"pansion & recoil of the lun#

an% therefore al'eoli with the mo'ement of the o'erlyin#structures


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Functional Anatomy Pleural :emrane Detail

+ohesion etween parietal an% 'isceral layers is%ue to serous flui% in the pleural ca'ity

) Flui% 46; ml of flui%5 creates an attraction etweenthe two sheets of memrane

) As the parietal memrane e"pan%s %ue toe"pansion of the thoracic ca'ity it


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Functional Anatomy $he Respiratory $ree

connectin# the e"ternal en'ironment to the

e"chan#e portion of the lun#s

similar to the 'ascular componentlar#er airway 1 hi#her flow & 'elocity

) small cross?sectional area

smaller airway 1 lower flow & 'elocity

) lar#e cross?sectional area


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Functional Anatomy $he Respiratory $ree9pper respiratory tract is for all intensi'e purposes a sin#le lar#e

con%ucti'e tue$he lower respiratory tract starts after the laryn" an% %i'i%es

a#ain an% a#ain@an% a#ain to e'entually #et to the smallestre#ions which form the e"chan#e memranes) $rachea

) Primary ronchi

) Secon%ary ronchi

) $ertiary ronchi

) Bronchioles) $erminal ronchioles

) Respiratory ronchioles withstart of al'eoli outpouches

) Al'eolar %ucts with outpouchin#sof al'eoli

conductive portion

e"chan#e portion


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Functional Anatomy /hat is the function of the upper

respiratory tract0/arm

(umi%ifyFilter

Vocalie

Raises

incomin# air to

6 +elsius

Raises

incomin# air to

3;; humi%ity

Forms

mucociliaryescalator


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Functional Anatomy /hat is the function of the lower respiratorytract0!"chan#e of #ases @. Due to

) (u#e surface area 1 3"3;C m- of type al'eolar cells

4simple s>uamous epithelium5) Associate% networ2 of pulmonary capillaries

;?E; of the space etween al'eoli is fille% with loo% inpulmonary capillary networ2s

) !"chan#e %istance is appro" 3 um from al'eoli to loo%*

Protection) Free al'eolar macropha#es 4%ust cells5) Surfactant pro%uce% y type al'eolar cells 4septal

cells5


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Functional Anatomy +haracteristics of e"chan#e memrane

(i#h 'olume of loo% throu#h hu#e capillarynetwor2 results in)

Fast circulation throu#h lun#sPulmonary circulation 1 CLmin throu#h lun#[email protected] circulation 1 CLmin throu#h entire o%y*

) Bloo% pressure is low@:eans

? Filtration is not a main theme here, we %o not want anet loss of flui% into the lun#s as rapi%ly as thesystemic tissues

? Any e"cess flui% is still returne% 'ia lymphaticsystem


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Functional Anatomy Sum?up of functional anatomy

Ventilation0

!"chan#e0

Vocaliation0Protection0


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Respiratory PhysiologyGas Laws

Basic Atmospheric con%itionsPressure is typically measure% in mm (# Atmospheric pressure is ; mm (# Atmospheric components

) 8itro#en 1 of our atmosphere) "y#en 1 -3 of our atmosphere

) +aron Dio"i%e 1 .;66 of our atmosphere

) /ater 'apor, 2rypton, ar#on, @. :a2e up the rest

A few laws to rememer

DaltonHs lawFic2Hs Laws of DiffusionBoyleHs Law %eal Gas Law


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DaltonHs LawLaw of Partial Pressures

)


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Fic2Hs Laws of Diffusion$hin#s that affect rates of %iffusion

) Distance to %iffuse

) Gra%ient sies) Diffusin# molecule sies

) $emperature

/hat is constant & therefore out of our realm of

concern0) So it all comes %own to partial pressure #ra%ients of

#ases@ %etermine% y DaltonHs Law*


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BoyleHs LawDescries the relationship etween pressure an%

'olume

)


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(ow %oes BoyleHs Law wor2 in us0 As the thoracic ca'ity 4container5 e"pan%s the 'olume must up

an% pressure #oes %own) f it #oes elow ; mm (# what happens0

As the thoracic ca'ity shrin2s the 'olume must #o %own an%

pressure #oes up) f it #oes ao'e ; mm (# what happens


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%eal Gas law$he pressure an% 'olume of a container of #as is

%irectly relate% to the temperature of the #as an%

the numer of molecules in the container PV 1 nR$

) n 1 moles of #as

) $ 1 asolute temp

) R 1 uni'ersal #as constant I .637C JKmol

Do we care0


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+anHt for#et aout poor +harles an% his law or

(enry an% his law Aptly name% @ +harlesHs Law & (enryHs Law

As the temp #oes up

in a 'olume of #as the

'olume rises

proportionately

V∝$

At a constant temperature, the amount of a #i'en #as

%issol'e% in a #i'en type an% 'olume of li>ui% is

%irectly proportional to the partial pressure of that #as

in e>uilirium with that li>ui%.

R

the soluility of a #as in a li>ui% at a particular

temperature is proportional to the pressure of that gas

ao'e the li>ui%.

*also has a constant which is different for each gas


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Ventilation

$erminolo#y nspiration 1 the mo'ement of air into the respiratory tracts

4upper & lower5!"piration 1 mo'ement of air out of the respiratory tracts

Respiratory cycle is one inspiration followe% y an e"piration +ause of nspiration0

Biolo#ical answer ) +ontraction of the inspiratory muscles causes an increase in the

thoracic ca'ity sie, thus allowin# air to enter the respiratory tract

Physics answer ) As the 'olume in the thoracic ca'ity increases 4%ue to inspiratory

muscle action5 the pressure within the respiratory tract %rops elowatmospheric pressure, creatin# a pressure #ra%ient which causesmolecular mo'ement to fa'or mo'in# into the respiratory tract

+ause of !"piration0


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Ventilation

Besi%es the

%iaphra#m 4only

creates aout

;?C of the

'olume chan#e5what are the

muscles of

inspiration &

e"piration0


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Ventilation

hat is the relationship

!etween alveolar pressure and

intrapleural pressure and the

volume of air moved"


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Ventilation

/hat are the %ifferent respiratory patterns0Muiet reathin# 4rela"e%5

Force% inspirations & e"pirations

Respiratory 'olumes follow these respiratorypatterns@


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Ventilation


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Ventilation

nspirationccurs as al'eolar pressure %rops elow atmospheric

pressure) For con'enience atmospheric pressure 1 ; mm (#

A 4?5 'alue then in%icates pressure elow atmospheric P

A 4N5 'alue in%icates pressure ao'e atmospheric P

) At the start of inspiration 4time 1 ;5,atmospheric pressure 1 al'eolar pressure

? 8o net mo'ement of #ases*

) At time ; to - secon%s!"pansion of thoracic ca#e an% correspon%in# pleural memranes

an% lun# tissue causes al'eolar pressure to %rop to ?3 mm (#

Air enters the lun#s %own the partial pressure #ra%ient


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Ventilation

!"pirationccurs as al'eolar pressure ele'ates ao'e

atmospheric pressure %ue to a shrin2in# thoracicca#e) At time -?7 secon%s

nspiratory muscles rela", elastic tissue of correspon%in#structures initiates a recoil ac2 to restin# state

$his %ecreases 'olume an% correspon%in#ly increasesal'eolar pressure to 3 mm (#

? $his is ao'e atmospheric pressure, causin#@0

) At time 7 secon%s Atmospheric pressure once a#ain e>uals al'eolar pressure

an% there is no net mo'ement


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Ventilation

Both inspiration an% e"piration can e

mo%ifie%Force% or acti'e inspiration

Force% or acti'e e"piration

$he lar#er an% >uic2er the e"pansion of the

thoracic ca'ity, the lar#er the #ra%ient an%

) $he faster air mo'es %own its pressure

#ra%ient


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Ventilation

$hin#s to consi%er surfactant effect

airway %iameter

:inute 'olume respiration 4'entilation rate times

ti%al 'olume5 & anatomical %ea% space)

Lea%in# to a more accurate i%ea of al'eolar 'entilationrates

+han#es in 'entilation patterns


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Ventilation

Surfactant is pro%uce% y the septal cellsDisrupts the surface tension & cohesion of water molecules mpact0

) pre'ents al'eoli from stic2in# to#ether %urin# e"piration


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Ventilation

Airway %iameter

& other factors

that affect airwayresistance0


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Ventilation

$he relationship etween minute 'olume 4total pulmonary 'entilation5an% al'eolar 'entilation & the suse>uent


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Next ime!

Diffusion an% SoluilityGas composition in the al'eoli

Gas e"chan#e

Gas transport in loo%

Re#ulation of pulmonary function


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DIFFUSION OFGASES


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Objectives

$o un%erstan% the %iffusion of #ases in the

lun#Define %iffusion an% contrast with ul2 flow

State Fic2Hs law for %iffusionDistin#uish etween %iffusion limitation an%

perfusion limitation

Descrie the %iffusion of o"y#en from the al'eoli

into the loo%

Descrie the %iffusion of +- from loo% to al'eoli

Define %iffusin# capacity an% %iscuss its

measurement


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Airway Brancin!

#rachea 0

$ain %ronchi 1

&o!ar %ronchus '

Segmental %ronchus ()*

%ronchioles +)1+

#erminal %ronchioles 16

Resp, %ronchioles 1-)1.

/lveolar ucts '0)''

/lveolas Sacs '(

SourceO S!!R $rainin# /esite

4trainin#.seer.cancer.#o'5


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B"#$ F#%w vs& Di'"si%n

$he cross sectional areaincreases with airway#eneration.

Lar#e 'olumetime, with%ecreasin# 'elocity at anypoint. Imagine a fast flowing river

reaching a delta.

$he 'elocity of #as %urin#inspiration ecomes tiny atthe le'el of the respiratoryronchiole? at this le'el%iffusion ecomes the chiefmo%e of #as mo'ement.

SourceO 9n%etermine%


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Gas (%ve)ent *"e t%Di'"si%n Diffusion ? mo'ement of #as %ue to

molecular motion, rather than flow.

$he same as the sprea% of a scent in aroom, rather than win%.

Ran%om motion lea%s to %istriution of #asmolecules in al'eolus.


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as $ovement due to iffusion

SourceO J2rie#er 4wi2ime%ia.or#5


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Di'"si%n

Dri'en y concentration #ra%ientsO%ifferences in partial pressure of the

in%i'i%ual #ases.

:o'ement of - an% +- etween thele'el of the respiratory ronchiole an%that of the al'eolar space %epen%s onlyon %iffusion.

$he %istances are small, so %iffusionhere is fast.

Di'"si%n %+ Gas Tr%"! te


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Pathway of %iffusion

Di'"si%n %+ Gas Tr%"! teA#ve%#ar ,a##

Al'eolar airspace

SourceO 9n%etermine%


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Di'"si%n %+ O-y!en Acr%sste A#ve%#ar ,a##

2ulmonar3 Surfactant

/lveolar Epithelium

/lveolar Interstitium

Capillar3 Endothelium

2lasma

Red %lood Cell

Hemoglo!in

DiffusesDissol'es

DiffusesDissol'es

DiffusesDissol'es

DiffusesDissol'es

DiffusesDissol'es

Bin%s

Fi $. L +


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Fic$.s Law +%rDi'"si%n

Vgas 4 / x x 521 2'7

#

V#as 1 'olume of #as %iffusin# throu#h

the tissue arrier per time, in mlmin

A 1 surface area a'ailale for %iffusion

D 1 %iffusion coefficient of the #as 4%iffusi'ity5$ 1 thic2ness of the arrier

P3 P- 1 partial pressure %ifference of the #as


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Di'"sivity

- has lower :/ than +-

Soluility of +- is -7" that of -

+- %iffuses -;" more rapi%ly throu#h the al'eolar

capillary arrier than -

D ≅ Soluility√:/

Di'"si%n Acr%ss a


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Di'"si%n Acr%ss a(e)brane

BQO 9ni'ersity of :ichi#an :e%ical SchoolhttpOcreati'ecommons.or#licensesy6.;%ee%.en

Li)itati%ns %+ Gas


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Li)itati%ns %+ GasTrans+er Diffusion +oefficient.

Different #ases eha'e %ifferently.

Surface Area an% $hic2ness of the al'eolar

wall. Partial Pressure Gra%ient across the al'eolar

wall for each in%i'i%ual #as.

Depen%s on oth al'eolar an% mi"e% 'enouspartial pressure 4start of capillary5.


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/an!e in B#%%* Partia#


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+aronmono"i%e

/an!e in B#%%* Partia#Press"re %+ Tree Gases witTi)e in te /a0i##ary

SourceO Pulmonary Physiology , $he :cGraw?(ill +ompanies, nc., -;;

N O is Per+"si%n


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N1O is Per+"si%n

Li)ite*8- is 'ery solule in iolo#ical tissues an%

%iffuses rapi%ly.

Pc8- rises rapi%ly in the al'eolar capillary

Muic2ly ha'e Pc8- 1P A

8-.Because there is no pressure #ra%ient, no

%iffusion occurs after aout ;.3 sec.Fresh loo% enterin# the capillary has not

yet e>uilirate% an% can still ta2e up 8-.ncrease% loo% flow will increase #as

transfer

$ransfer of 8- is perfusion limite%.

/an!e in B#%%* Partia#


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/an!e in B#%%* Partia#Press"re %+ Tree Gases witTi)e in te /a0i##ary

+aron:ono"i%e


/ b ( i* i Di' i


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/arb%n (%n%-i*e is Di'"si%nLi)ite*

Bloo% P+ rises 'ery slowly ecause + is

oun% to (, with 'ery little %issol'e%.

+apillary Pc+ %oes not approach P A+.

Partial pressure #ra%ient is maintaine%throu#hout the time the loo% is in the

capillary.

) Diffusion continues throu#hout this time.

$ransfer of + is limite% y %iffusi'ity,surface area, an% thic2ness of the wall.


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Trans+er %+ O-y!en



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Trans+er %+ O-y!en

9n%er normal con%itions, Pc- reaches P A- aout 36of the %istance throu#h the capillary.

$herefore un%er normal con%itions transfer is perfusion

limite%.

/ith e"ercise, the time loo% spen%s in the capillary isre%uce%? no lon#er perfusion ut %iffusion limitation.

n the settin# of thic2ene% al'eolar wall, transfer isre%uce%./ith se'erely %isture% %iffusion, there is limitation e'en at rest

T + + O i Li it *


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Trans+er %+ O-y!en is Li)ite*at L%w A#ve%#ar O1



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Trans+er %+ /O1

s transfer of

+- %iffusion

or perfusion

limite%0



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Trans+er %+ /O1

/hy is the transfer of +- so similar to that of

-0

Diffusi'ity of +- is -;" than that of -

Partial pressure #ra%ient of +- is 7C→7;

Partial pressure #ra%ient of - is 3;;→7;

V#as 1 A " D " 4P3 P-5

$

Fic$.s Law +%r


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Fic$ s Law +%rDi'"si%n

V#as 1 'olume of #as %iffusin# throu#h

the tissue arrier per time, in mlmin

A 1 surface area a'ailale for %iffusion

D 1 %iffusion coefficient of the #as 4%iffusi'ity5

$ 1 thic2ness of the arrier P3 P- 1 partial pressure %ifference of the #as

4A"D5$ 1 %iffusin# capacity of the lun# 4DL5

( )21)( P P xT

AxDV gas −=


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Di'"sin! /a0acity

(eas"rin! Di'"sin!


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(eas"rin! Di'"sin!/a0acity nhale mi"ture containin# 2nown concentration of tracer #as.

Allow %iffusion from al'eolus into loo%.

:easure concentration of tracer in e"hale% #as.

+alculate rate of remo'al of tracer #as y %iffusion into loo%an% the partial pressure #ra%ient from al'eolus into loo%.

+hoice of #asO Rea%ily a'ailale.

!asily measure%. Diffusion limite%. 8o arterial partial pressure.


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V

O2

= DL- = ml O2 /min( PA O2 O2)P

C

= V 2

AxD

T= D

LO

2

"e #oul$ %se &LO'

DL- O

( PA O2 O2

)PC

BQO 9ni'ersity of :ichi#an :e%ical School

httpOcreati'ecommons.or#licensesy6.;%ee%.en

/arb%n (%n%-i*e is an I*ea# Gas


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/arb%n (%n%-i*e is an I*ea# Gas+%r (eas"rin! Di'"sin! /a0acity

+ in%s a'i%ly to

hemo#loin.

/hile + content of theloo% rises, the P+ in

loo% rises 'ery slowly.

$he #ra%ient of partialpressures from al'eolus

to loo% remains almost

constant %urin# test

+aron

:ono"i%e

SourceO Pulmonary Physiology , $he

:cGraw?(ill +ompanies, nc., -;;

/ b ( i* ( t


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8ormal &C9 4 '0)(0 ml:min:mmHg

/arb%n (%n%-i*e (eas"re)ent%+ Di'"sin! /a0acity

DLCO = V

•

CO

P ACO

0≈ PcCO

P cCO P ACO

V DLCO

CO

−=

•


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/%n*iti%ns tat I)0act


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/%n*iti%ns tat I)0actDi'"si%n /a0acity +%r /O&

Decrease% Surface Area.Destruction of Al'eolar /all

ncrease% Barrier $hic2ness. Anemia.

T

AxD DLCO =

H%w w%"#* te F%##%win! /an!e


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H%w w%"#* te F%##%win! /an!ete Di'"si%n /a0acity %+ te L"n!s2

+han#in# from supine to upri#ht

!"ercise

Anemia

Valsal'a maneu'er

Low car%iac output %ue to hemorrha#e

!mphysema

Pulmonary firosis

Documents

03. Respiratory Physiology