10. Acute Respiratory Distress Syndrome

8/11/2019 10. Acute Respiratory Distress Syndrome

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Acute Respiratory Distress

SyndromeDr. Vanya Chugh

University College of Medical Sciences & GTBHospital, Delhi


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Timeline

In 1967 Ashbaugh, Bigelow, Petty, Levine - described Acute

es!iratory "istress #yndro$e in adults

In 1971, Petty and Ashbaugh $odi%ied its na$e %ro$ &acute' to &adult'

es!iratory "istress #yndro$e( to di%%erentiate it %ro$ its newborn

counter!art

In 197), *ebb and +ierney con%ir$ed the eistence o% ventilator

associated lung inury

In 199., /ic0ling et al introduced the conce!t o% !er$issivehy!erca!nia


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Timeline

In 199, A$erican 2uro!ean 3onsensus 3on%erence 4A2335 gave

standardied de%inition %or A"#

In 1997, +re$blay et al introduced the conce!t o% biotrau$a

In 199, A$ato et al, conducted 3+ - decrease in $ortality usinglow tidal volu$e ventilation and high P22P 4o!en lung strategy5

In ..., A"# networ0 trial de$onstrated the bene%its o% low tidal

volu$e and P22P ventilation


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Definitions of ARDS

Ashbaugh and colleagues, 1967

#evere dys!nea

+achy!nea 3yanosis re%ractory to oygen thera!y

"ecreased !ul$onary co$!liance

"i%%use alveolar in%iltrates on chest radiogra!h8

Loosely de%ined criteria

"e%inition o% hy!oe$ia inconsistent


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Chest Radiology findings Score o alveolar consolidation .

:ne ;uadrant 1

+wo ;uadrant

+hree ;uadrant l !neu$onia,

atelectasis, cardiogenic !ul$onary ede$a

PA:P o% 1 $$ /g >absence o% clinical evidence o% le%t atrial

hy!ertension D PA:PD !oor esti$ate o% PE/, %alsely raised with high

airway !ressures

Acute lung inury !resent i% Pa:1>=I:1is


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Delphi de(inition '))*$ o( ARDS

"iagnosis D 1- ) !resent with @a and>or @b

18 Pa:1>=i:1ratio G .. on P22P H 1.88 Bilateral airs!ace disease D H ;uadrants, %rontal chest -ray

subective %inding o% 3/=

4including use o% PA catheter and>or echo i% clinically indicated5

@a8 #tatic res!iratory co$!liance @.$l>c$ /:

4!atient sedated, +E $l>0g, P22P H 1.8

@b8 Presence o% direct or indirect ris0 %actor associated with lung

inury8


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Delphi de(inition o( ARDS contd.

Airs!ace disease !resence o% one or $ore o% the %ollowing-

18 Air brochogra$

8 Acinar shadows


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Synonyms o( ARDS

#hoc0 lung Pu$! lung +rau$atic wet lung Post trau$atic atelectasis

Adult hyaline $e$branedisease

Progressive res!iratory distress Acute res!iratory insu%%iciency

syndro$e /ae$orrhagic atelectasis /y!oic hy!erventilation

Post!er%usion lung :ygen toicity lung *et lung *hite lung

+rans!lant lung "a ang lung "i%%use alveolar inury Acute di%%use lung inury

oncardiogenic !ul$onaryede$a8 Progressive !ul$onary

consolidation


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+pidemiology o( ARDS

"i%%icult to esti$ate

Lac0 o% standardiation o% the de%inition

"i%%erence in $ethodology

J3LIP study 41999-...5 done on A"# !atients as !er A233

criteria esti$ated -

- incidence o% ALI 789>la0h !erson years

- $ortality rate


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,recipitating -actors

)irect *ung +n'ury

Pneu$onia

As!iration o% gastric contents

Pul$onary contusion

ear-drowning

+oic inhalation inury

+ndirect *ung +n'ury

#e!sis

#evere trau$a

Culti!le bone %ractures

=lail chest

/ead trau$a

Burns

Culti!le trans%usions

"rug overdose

Pancreatitis

Post-cardio!ul$onary by!ass


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Di((erential ris (actors

3hronic alcohol abuse

Absence o% "C

Age

ender #everity o% illness APA3/2 score

2cessive blood trans%usion

3igarette s$o0ing


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,athophysiology in ARDS

ased on the histological aearance -

$xudati&e hase (.- days" Alveolar and interstitial ede$a 3a!illary congestion "estruction o% ty!e I alveolar cells

2arly hyaline $e$brane %or$ation#roliferati&e #hase (/-1. days"

Increased ty!e II alveolar cells 3ellular in%iltration o% alveolar se!tu$ :rganisation o% hyaline $e$branes

0ibrotic #hase (1. days" =ibrosis o% hyaline $e$branes and alveolar se!tu$ Alveolar duct %ibrosis


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,athology in ARDS

Cechanis$s in early !hase - elease o% in%la$$atory cyto0ines += al!ha, IL- 1,6, =ailure o% alveolar ede$a clearance, e!ithelial and endothelial da$age Increased !er$eability o% alveolo ca!illary $e$brane

eutro!hil $igration and oidative stress Procoagulant shi%t %ibrin de!osition #ur%actant dys%unction

Cechanis$ in late 4re!air5 !hase Fibroproliferation-+= beta, CCPs, tho$bos!ondin, !las$in, :#

Remodelling- $atri and cell sur%ace !roteoglycans, CCP, i$balance o%coagulation and %ibrinolysis8


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,athophysiology o( ARDS


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D/D 0 1ydrostatic pulmonary edema

P3*P H 1 $$/g

3auses D

3ardiogenic LE= 4eg8 CI, $yocarditis5

cardiac valvular disease 4aortic, $itral5 Eascular syste$ic /+, !ul$onary e$bolis$

Eolu$e overload - ecessive iv %luids, renal %ailure


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Cardiogenic 2s 3on4cardiogenic edema

1818 Prior h>o cardiac diseasePrior h>o cardiac disease

8+hird heart sound8+hird heart sound


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Management

2reat!ent of the reciitating cause

3echanical &entilation 3ore ventilator $anage$ent- !rotective lung ventilation strategy

- role o% &o!en lung a!!roach' Aduncts to core ventilation -

18 =luid restriction

8 Per$issive hy!erca!nia


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Management contd.

4on con&entional5Sal&age inter&entions

a8 /igh %re;uency ventilation

b8 Airway !ressure release ventilation

c8 +racheal gas insu%%lation

d8 Inverse ratio ventilatione8 Inhaled nitric oide

%8 Inhaled !rostacyclin

g8 3orticosteroids

h8 #ur%actant ad$inistrationi8 Li;uid ventilation

8 2tracor!oreal $e$brane oygenation Suorti&e theray nutrition, !revention o% in%ection


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Concept o( VALI

Cechanical ventilation - Basic care in critically ill I3N !atients

Cay cause or worsen lung inury ventilator induced>associated lung

inury

3o$!onents Barotrau$a

Eolutrau$a

Atelectrau$a

Biotrau$a


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VALI and M5DS


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Concept o( 67a7y lung8

Put %orward by attinoni and colleagues %irst in 197

Lung inury in A"# - non ho$ogenous, basal

2de$a and consolidation ? de!endent lung regions - M density o% dorsal

regions Aerated ventral regions &baby lung' 4


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Management

*ung rotecti&e &entilation AR)S net%or rotocol

oals

OxygenationD Pa:1@@-. $$/g, or #!:1 9)K 4ecluding

!regnancy, intracranial hy!ertension or stro0e where #a:1 goal?9)K5 VentilationD

+idal volu$e D )-6 $l>0g ideal body weight

Plateau !ressure D


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Canage$ent contd8

Oxygenation Initially high =io1 given 418.5 to correct hy!oia

=io1 and P22P adusted to the lowest level co$!atible with the

oygenation goals

=io1and P22P adusted in the %ollowing %ied co$binationsO%io1>P22P4$$/g5

.8< .8) .8) .8@ .8@ .86 .87 .87 .87 .8 .89 .89 .89 18.

@ @ 1. 1. 1. 1 1) 1) 1) 16 1 .-)

=I:

P22P


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Management contd

+nitial &entilator set u and ad'ust!ents

S2$# 1- 3alculation o% ideal body weight4IB*5D

=or $ales, IB*40g5 @.Q8


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Management contd

S2$# 8 - Eolu$e assist control selected as ventilator $ode

Initial tidal volu$e 4+E5 set at $l>0g IB*

+E reduced by 1$l>0g IB* hourly until +E 6$l>0g IB*

Initial ventilator rate set to $aintain baseline $inute ventilation4 not?$in5

+E and res!iratory rate adusted to achieve the !/ and !lateau

!ressure goals

Ins!iratory %low rate set above !atients de$and 4usually ?.L>$in5


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:!en Lung A!!roach

Introduced by A$ato et al in 199 use o% low tidal volu$e Q high

P22PQ recruit$ent 4:!en lung strategy5 reduce $ortality in A"#

Caintaining in%lation R de%lation between in%lection !oints during entire

res!iratory cycle

Eentilatory settings - P22P ?P%le,R +E reduced so that P!lat NIP

Advantages- avoids re!etitive o!ening and closing o% alveoli 4EALI5

- $ini$ies shear inury


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5pen Lung Approach,ressure4Volume Cur2e


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Management


3echanical &entilation 3ore ventilator $anage$ent !rotective lung ventilation strategy

role o% &o!en lung a!!roach' Aduncts to core ventilation

1 0luid restriction



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-luid restriction in ARDS

Rationale alveolar %looding de!ends on D

18 3a!illary hydrostatic !ressure

8 :ncotic !ressure


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-luid therapy in ARDS

eco$$ended D

3entral venous !ressure guided thera!y 1.-1) $$/g

( ARDS Network Trial 2003)

estricted %luid inta0e

Increased urine out!ut "iuretics or +

ot reco$$ended D

Easodilators Albu$in


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Management


3echanical &entilation 3ore ventilator $anage$ent - !rotective lung ventilation strategy

- role o% &o!en lung a!!roach' Aduncts to core ventilation


8 #er!issi&e hyercania


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,ermissi2e 1ypercapnia

/ic0ling and colleagues 199.

T"egree o% hy!erca!nia !er$itted in !atients subected to lower tidal

volu$esU

N!!er li$it not de%ined( ?1.. $$/g avoided

Advantages

Increased sur%actant secretion 4ani$al $odels5 i$!roved E>V $atch,

oygenation 4i$!roved co$!liance5

Increased cardiac out!ut and oygen delivery 4sy$!athoadrenal e%%ects!redo$inate over cardiode!ressant e%%ects5

Increased cerebral blood %low and tissue oygenation


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,ermissi2e 1ypercapnia

3oncerns

Increase in !ul$onary vascular resistance

I$!aired dia!hrag$atic %unction 4i$!airs a%%erent trans$ission5

"ecrease in cardiac contractility aised intracranial tension

Individualie and treat


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Management


3echanical &entilation 3ore ventilator $anage$ent - !rotective lung ventilation strategy

- role o% &o!en lung a!!roach' Aduncts to core ventilation



/ #rone ositioning

)8 ecruit$ent $aneuvers


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,rone ,osition Ventilation

=irst suggested by Piehl and Brown in 1976

:%%ers i$!roved oygenation byD

Increased =3

3hange in regional dia!hrag$ $otion "istribution o% !er%usion

Better clearance o% secretions


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,rone ,osition Ventilation

#ud and colleagues conducted $eta-analysis o% 1< 3+s 41@@9

!atients5 on su!ine and !rone !osition ventilation in A"#>ALI

!atients

Cedian CE o% 1 hours 4 )-)hrs5 %or ) days4 1-1. days5

3onclusion -cannot be reco$$ended %or routine C

-no evidence o% i$!roved survival

attinoni et al suggested no overall reduction in $ortality ece!t invery sic0 !atients 4 #AP# II #core [email protected]

o decrease in ventilator associated !neu$onia


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,ro7lems o( prone position

=acial ede$a

Airway obstruction

"i%%iculties with enteral %eeding

+ransitory decrease in oygen saturation

/y!otension R Arrhyth$ias

Eascular and nerve co$!ression

Loss o% venous accesses and !robes

Loss o% chest drain and catheters

Accidental etubation

A!ical atelectasis d>t incorrect !ositioning o% the tracheal tube

Increased need %or sedation


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Recruitment maneu2ers

/igh !ressure in%lation $aneuver ai$ed at te$!orarily raising the

trans!ul$onary !ressure above levels ty!ically obtained with

$echanical ventilation

+y!es 2levated sustained !ressures D ). c$ /: %or ). seconds

#igh breaths D M tidal volu$e > P22P %or one or several breaths

2tended sigh breath D E3E with P22P well above LIP %or a longer

ti$e

Core e%%ective in early ALI and those with $ore ho$ogenous

disease( atelectasis ? consolidation8


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Recruitment maneu2ers

Adverse e%%ects

/y!otension

Barotrau$a

aised I3P /ae$odyna$ic instability


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Management contd.

4on con&entional5Sal&age inter&entionsa8 /igh %re;uency ventilation





g8 3orticosteroids

h8 #ur%actant ad$inistration

i8 Li;uid ventilation



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1igh -re9uency Ventilation

Cechanical ventilatory su!!ort using higher than nor$al breathing

%re;uencies

#$aller tidal !ressure swings 4within in%lection !oints5 along with a!t $!aw

#$aller tidal volu$es and higher $ean !ressure utilied %or lung !rotection

#!ecial ventilators re;uired

+y!es - /igh =re;uency Wet Eentilation 4/=WE5

/igh =re;uency :scillatory Eentilation 4/=:E5


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1-V

/=WE

A nole>inector creates high velocity &et' o% gas directed into thelung

Inectors 1-$in

Available %or neonatal and !aediatric use only

/=:E

3haracteried by ra!id oscillations o% a dia!hrag$ 4at < to 1. hert i8e1. to 16. breaths>$in5 driven by a !iston !u$!

=re;uencies available


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1-V contd

Advantages

Better oygenation and ventilation

Aids lung recruit$ent 4high $!aw5

educes oygen toicity 4high $!aw5 Cini$ies EILI

"isadvantages

"elivered tidal volu$es di%%icult to $onitor "ee! sedation and>or !aralysis re;uired

Inade;uate hu$idi%ication

"irect !hysical airway da$age


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Air:ay ,ressure Release Ventilation

Alternative $ode o% ventilation that a!!lies a %or$ o% 3PAP that is

released !eriodically, aug$enting 3:1release8

Pressure li$ited, ti$e cycled $ode

Per$its s!ontaneous ventilation throughout the res!iratory cycle

Based on the &o!en lung' conce!t $ai$ie and $aintain

recruit$ent throughout the res!iratory cycle

A,RV contd


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A,RV contd

Nses airway !ressures P highand P low( set ti$e !eriods + high

and + low, usually + high?+ low P highis set above the closing !ressure o% recruitable alveoli 4lower

in%lection !oint5

#et + high$aintains the P high%or several seconds

+ lowhel!s re$ove 3:1


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A,RV contd

Potential bene%its D

M E>V $atch

S dia!hrag$atic atro!hy during critical illness

M cardiac out!ut and oygen delivery M s!lanchnic !er%usion

M renal and he!atic %unction

=ewer days on $echanical ventilation

=ewer days in I3N


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Tracheal ;as Insu((lation

or$al ventilatory cycle - bronchi and trachea %illed with alveolar gas

at end e!iration

In the net ins!iration, 3: laden gas %orced bac0 into alveoli8

+I - strea$ o% %resh gas 4at )-L>$in5 insu%%lated through a s$all

catheter>channels in the wall o% endotracheal tube into the lower

trachea

3: laden gas %lushed out o% the trachea be%ore net ins!iration


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Tracheal ;as Insu((lation contd.

)isad&antages

"essication o% secretions

Inade;uate hu$idi%ication

Airway $ucosal inury Accu$ulation o% secretions in the +I catheter

3reation o% auto P22P %ro$ e!iratory %low and resistance o% the

ventilator-ehalation tubes and valve


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Inverse atio Eentilation

Alternative $ode o% ventilation

2ntails use o% !rolonged ins!iratory ti$es 4ID2?15 using volu$e or

!ressure cycled $ode o% $echanical ventilation

Pro!osed $echanis$ o% action alveolar recruit$ent at lower airway

!ressures, o!ti$al distribution o% ventilation

3oncerns generation o% auto P22P

reduced cardiac out!ut 4 M CAP5


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Inhaled 3itric 5


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Inhaled ,rostacyclin

3ause vasodilation, inhibit !latelet aggregation, reduction o%

neutro!hil adhesion and activation, S !ul$onary hy!ertension,

i$!roved oygenation

Cini$al syste$ic e%%ects, har$less $etabolites, no re;uire$ents %or

$onitoring

Both !ositive and negative results obtained in various trials

Presently not reco$$ended


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Corticosteroids

2stablished A"# characteried by alveolar %ibrosis

Anti-in%la$$atory and anti%ibrotic !ro!erties o% steroids !robable

role in A"#

o role in !reventing but $ay hel! in treating A"#

Sur(actant Therapy


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Sur(actant Therapy

educes alveolar sur%ace tension

Prevents alveolar colla!se

Anti in%la$$atory !ro!erties

Anti $icrobial !ro!erties

2ogenous sur%actant success%ul in neonatal res!iratory distresssyndro$e 4reduced sur%actant !roduction5

A"# in adults increased sur%actant re$oval, altered co$!osition,

reduced e%%icacy, reduced !roduction

#ur%actant thera!y not reco$$ended in adults


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Li9uid Ventilation

Involves %illing the lung with li;uid

e$oves the air li;uid inter%ace and su!!orts alveoli, !revents

colla!se

Per%luorocarbons have low sur%ace tension, dissolve oygen and

carbon dioide readily, non toic, $ini$ally absorbed, eli$inated by

eva!oration though lungs

Lowered sur%ace tension $ay i$!rove alveolar recruit$ent, arterial

oygenation, increased lung co$!liance

3an recruit de!endent alveoli 4advantage over P22P5


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Li9uid Ventilation contd.

+y!es D

2otal %illing the entire lung with li;uid, ventilated with a s!ecial ventilator

- 2!ensive

#artial - %illing the lung to =3 with li;uid, ventilated with conventional

ventilator

- A!!ro!riate dose o% P=3 still to be deter$ined

- M chances o% !neu$othoraces, hy!oic e!isodes, hy!otensive e!isodes

P=3 radiodense i$!ossible to detect in%ection or %ollow the !rogress o%

healing in a chest radiogra!h

Li;uid ventilation is not ="A a!!roved


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+


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+CM5 contd.

+y!es

Eeno - arterial a catheter !laced in both vein and artery8 Provides

su!!ort both %or heart and lungs

Eeno - venous single double lu$en catheter !laced in the vein8

Provides su!!ort only %or lungs

23C: allows ventilator !ressures and volu$es to be decreased to

!revent %urther EILI

eduction in intra - thoracic !ressure allows %luid re$oval %ro$ lungs

with less ris0 o% cardiovascular instability


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+CM5 contd

3o$!lications D

/ae$orrhage

enal %ailure

/ae$olysis /y!otension> hy!ertension

Pneu$othora

In%ections


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Management contd.

Sal&age inter&entionsa8 /igh %re;uency oscillatory ventilation





g8 3orticosteroids





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3utrition

2nteral over !arenteral

/igh %at low carbohydrate diet advocated - S 3:1

I$$uno $odulatory nutrients

-a$ino acids - arginine and gluta$ine -ribonucleotides

-o$ega-< %atty acids

"iet rich in %ish oil, X-linolenic acid, and antioidants

#tandard nutritional %or$ulations reco$$ended


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Anti7iotics In%ection - !resent initially D non!ul$onary se!sis

"evelo! later - nosoco$ial in%ections D !neu$onia and catheter-relatedse!sis8

Ai$ D identi%y, treat, and !revent in%ections8

Cost !neu$onia ? 7 days

Pro$!t initiation o% a!!ro!riate e$!iric thera!y8

/and washing by $edical !ersonnel

ew areas D

- continuous suctioning o% subglottic secretions to !revent their as!iration

-develo!$ent o% new endotracheal tubes - resist %or$ation o% bacterial

bio%il$ that can be e$bolied distally with suctioning8


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Management contd.

4on con&entional5Sal&age inter&entionsa8 /igh %re;uency ventilation





g8 3orticosteroids





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Complications associated :ith ARDS

Pul$onaryDbarotrau$a ,volutrau$a, !ul$onary e$bolis$, !ul$onary%ibrosis, ventilator-associated !neu$onia 4EAP5, :ygen toicity

astrointestinalD hae$orrhage 4ulcer5, dys$otility, !neu$o!eritoneu$,

bacterial translocation

3ardiacD Arrhyth$ias, $yocardial dys%unction

enalD acute renal %ailure 4A=5, %luid retention

CechanicalDvascular inury, tracheal inury>stenosis 4result o% intubation

and>or irritation by endotracheal tube5

utritionalD $alnutrition, anae$ia, electrolyte de%iciency


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Long term se9uelae o( ARDS

Pul$onary %unction $ild i$!air$ent, i$!roves over 1 year

eurocognitive dys%unction

Post trau$atic stress disorder

Physical debilitation


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In(antile Respiratory Distress Syndrome

/yaline $e$brane disease

"e%iciency o% sur%actant D insu%%icient !roduction in i$$ature lungs,

i$$ature babies

enetic $utation in one o% the sur%actant !roteins, #P-B rare, %ull

ter$ babies

Prevention D avoidance o% !re$ature birth, corticosteroids

+reat$ent D sur%actant re!lace$ent

e%erences


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e%erences

Y /arrison's Princi!le o% Internal Cedicine, 16thed8

Y 3hristie W", Lan0en P8 Acute lung inury and the acute res!iratory distress

syndro$e8 3ritical 3are /all

Y =oner BW, orwood #/, +aylor *8 Acute res!iratory distress syndro$e8

3ritical 3are,


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Re(erences

Acute res!iratory distress syndro$e networ08 Eentilation with lower tidal volu$esas co$!ared with traditional tidal volu$es %or acute lung inury and the acuteres!iratory distress syndro$e8 2ngl W Ced8 ...()D1

10. Acute Respiratory Distress Syndrome

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