PressorUpdateWord格式文档下载.docx

PressorUpdateWord格式文档下载.docx

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4-Whatarethethreepartsofabloodpressure?

5-Whatdoes“pump”mean?

6-Whatis“inotropy”?

7-Whatabout“volume”?

8-What’s“crystalloid”?

9-Whatis“squeeze”?

10-Howdoesthisrelatetoshock?

10-1-PALines

10-2-Somethingthatwillmakeyoulookreallysmart!

11-Whichshockstatereflectsa“pump”problem?

12-Whatis“ejectionfraction”?

13-Whichshockstatereflectsvolume?

14-Whichshockstatereflectsarterialsqueeze?

15-Whatmeasurementsdoweuseatthebedsidefortreatingshockstates?

16-Howdopressorsfitintothetreatmentofshockstates?

17-Howdopressorsworkonreceptors?

17-1Agonizingreceptors

17-2Antagonizingreceptors

17-3SVR

18-Howareothershockstatestreated?

19-Arepressorsusedtotreathypovolemicshock?

Animportantpoint.Anotherone.

20-Whataboutcardiogenicshock?

21-Whatotherpressorsarethere?

22-WhatbasicconsiderationsshouldIkeepinmindwhenusingthesedrugs?

22-1-Settingupthedrips.

22-2-Drugrates.

23-ArethereothervasoactivesthatIneedtoknowabout?

24-Howdoweusevasopressin?

25-Whydon’tweusetheTrendelenburgpositionforhypotensionanymore?

26-AChartThingforthosewholikethem…

TheQuiz!

“Bloodpressuremedicines”comeinacoupleofvarieties:

therearesomethatmakebloodpressuregoup,andtherearethosethatmakeitgodown.Theword“pressor”isusuallyusedtomeanthefirstkind.Anotherwordthatdescribesthesedrugs（bothkinds）is“vasoactives”,whichistosay:

affectingbloodpressure,orheartrate,orboth.Themajoruseforpressorsisinthetreatmentofonekindofshockoranother.

n.（noun）

1.“Somethingthatjarsthemindoremotionsasifwithaviolentunexpectedblow.”

2.TherealizationthatyouareworkingintheMICU…

Shockisusuallydescribedasastateinwhichthebody’stissuesaren’tgettingenoughbloodflowforonereasonoranother.Theperipheraltissues–wayawayfromthemajorvessels,andsuppliedbysmallervesselswhoseperfusionsufferswhenbloodpressuredrops–losemuchofthebloodsupplythattheydependonforoxygenandnutrientdelivery.Sotheyswitchgearsatthecellularlevel:

theychangefromaerobicrespiration,inwhichtheyusedeliveredoxygentomakeenergy,toanaerobicrespiration,whichworks,butpoorly.Thebyproduct,or“engineemission”ofaerobicrespirationiscarbondioxide,whichwegetridofbybreathing.Buttheemissionfromanaerobicrespirationisunfortunatelylacticacid,andsincethebloodvesselsarenotcarryingwastesawayeffectively–beingunderperfused–thelacticacidbuildsup,creatingametabolicacidosis.Theacidosismakesbloodpressureevenhardertomaintain,sincemostpressorslikeadrenaline（epinephrine）andnorepinephrine（levophed）dependonthebloodpH–ifthepHistoolow,theywon’tworkverywell.

Yes–threemainones,buttounderstandthem,weneedtotalkabouthowexactlyabloodpressureismaintained.Itturnsoutthattherearethreemajorcomponentsofabloodpressure.

4-Whatarethethreecomponentsofabloodpressure?

Wethinkofthemas:

“pump”,“volume”,and“squeeze”.Ofcourse,it’slotsmorecomplicatedthanthat,andasalways,mostoftheinformationinallofthesearticlesiswritten“withalotofliesthrownin”–thereareshelvesoftextbooksthathavebeenwrittenoneachsubjectthatwetrytocoverinafewpages.Butthepointis:

howcanyouorganizetheideasinyourheadtofigurethingsoutatthebedside?

Quick-and-dirtyiswhatwillhelpmost…

Keepinmindaswegoalongthateachofthesecomponentsneedstobemeasured,andthatmanyofthetoolsweuseintheunitaredesignedtodojustthat.

5-Whatis“pump”?

Pumpistheheart.Anythinginterferingwithinotropy,heartrate,orcardiacoutput,beitanMI,anarrhythmia,ischemia–isapumpproblem.

Howmightyoumeasureyourpatient’sabilitytopump?

Numerically,Imean?

http:

//www.klangundkleid.ch/img/moebel/sofina/08510_double-stroke-hand-pump.jpg

Inotropymeans:

“howhardtheleftventricleisworkingtopump,toemptyitself”.

That’sthisone.Whydoweworryabouttheleftventriclesomuch,inrelationtobloodpressure?

Imean,weworryabouttheRVtoo–butforsortofdifferentreasons.TakealookatthearticleonPE’sformoreaboutthis.（www.icufaqs.org/PulmonaryEmbolism.doc）

Hmm–thinkwecouldmeasurethis?

//www.everyschool.org/u/wcms/tanaka/Heart.jpg

Easyenough:

thecirculatingvolumeinthebloodvessels.Youhavetoincludetherelativevolumesofredcellsandplasmatothisideathough–theremaybeplentyofredcells,butifapatient’splasmavolumeislow–whichistosayshe’sdehydrated,hypovolemic,butnotfrombleeding–youwouldn’tgivethatpersonblood,wouldyou?

Ortheotherwayaround–youwouldn’tgivejustcrystalloidtoapersonwithalowcritfrombleeding,wouldyou?

8-No.What’scrystalloid?

Any“clear-as-crystal”IVfluidis“crystalloid”–it’sawordusedforakindofIVvolumereplacement-asopposedto“colloid”,meaninganythingprotein-basedsuchasalbuminofonekindoranother,orplasma–butasIunderstandit,notredcells.Anyhow,right–youwouldcorrectvolumelosswithwhatthepersonneeded,basedonwhattheyneeded:

redcells,orthe‘”water”componentofthecirculatingvolume.

Howmightyoumeasureyourpatient’svolumestatus?

“Squeeze”hasactuallybeenusedaroundICUsforlongtimetomeantwodifferentthings–somepeopleuseittodescribehowtightthearterialbedis-whichistosayhowtight,orconstrictedtheentiresystemofarterialvesselsis.Otherpeopleuse“squeeze”tomeaninotropy.Iuseitthefirstway,becauseithelpsmethinkaboutwhat’shappeningtothepatient–it’sausefulconceptwhenyou’refacedwithahypotensivesituationthatyou’retryingtosortout.

Weneedtomeasurethistoo…

//www.mikkis.co.uk/admin/images/Stressball-Home.jpg

Thethreecomponentsofabloodpressureactuallyreflectthethreekindsofshockthatyou’relikelytoseeinintensivecare.Thetrickintreatingeachofthesecorrectlycomesfromourabilitytomeasureeachofthecomponentsprecisely.Anyideahowwemightdothat?

10-1-ThetoolyouneedinthissituationisaPAline–apulmonaryarterycatheter,alsoknowsasaSwan-Ganzline,orjusta“Swan”.

That’stheyellowthing,goingintothebluething,thereatthepatient’sear,sortof?

Whichisconnectedtothewhitething,goingintohisneck?

//www.castenholz.org/ptguide/special.htm

PAlinestellyoueverythingyouwanttoknow:

-howwellthepumpispumping（cardiacoutput,cardiacindex）

-howfulltherightsideoftheheartis（CVP）,andhowfulltheleftsideis（wedgepressure）–that’sthevolume…

-andhowwellyourpatient’sarteriescansqueeze:

that’stheSVR–the“systemicvascularresistance”…

PAlinesareseriousjuju–they’reinvasive,they’retrickytoplace,theyneedveryseriouscareandfeeding–infact,they’vegotawholeenormousFAQalltothemselves,andtheyneedone!

Butunderstandinghowpump,volumeandsqueezeallgotogetherisimportanttounderstandinghowpressorswork.Gotakealook!

（www.icufaqs.org/PALinesApril04.doc）

10-2-Somethingthatwillmakeyoulookreallysmart.

Analternative–ifyourpatienthasnoPA,butdoeshaveacentrallineandaradiala-line,youcancallthein-houseIABPtechtocomeanddoa“greendye”cardiacoutput.Theyhookupalittlecolor-measuringthingtothearterialline,andtheyinjectsomeformofdye-（probablygreen!

）-throughthedistalportoftheCVP.Thentheymeasurehowlongittakesforthedyetoshowupatthea-line,multipliedbythis,dividedbythat,alignedwiththecoefficientofHammerschmidt,overthesquareofthepatient’sshoesize…andoutcomethenumbers.Cool!

Thekindofshockthatreflects“pumpfailure”is“cardiogenic”shock,whichistosay:

“originatingintheheart”.Simpleidea:

thebloodpressureislowbecausethepumpisn’tpumping.ThisisusuallybecauseofasizableMI,butpeoplewithend-stageheartdiseaseofonekindoranother,suchascardiomyopathy（“heart-muscle-disease”）,orpeoplewhohavehadmultipleMI’s-leavingthemwithaverylowejectionfraction-canliveontheedgeofcardiogenicshockmuchofthetime.

12-Whatisejectionfraction?

“EF”istheamountofbloodejectedfromtheleftventricleintothearterialcirculationwitheverysystoliccontraction,expressedaspercent.Normalissomethinglike50-70%.Impressivelylowisusuallysaidtobelessthan30%,and“cardiaccripples”whocan’tgetupfromthechairwithoutshortnessofbreathsometimesruninthelowteens.

Here’stheLVattheendofdiastole–allfull,readytogo.