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Figure5.12.CT:Appendagitisepiploica(arrow).
Freefluid
Watchfor freefluid between the intestinalloops and elsewhere. The
fluiddensitygivesacluetoitsnature:forascitesitislikewater,0-20HU,
forpusbetween15and30HU,andforbloodabout50HU,butbeaware
thatthesespecificationsdon’talwaysallowanexactdifferentiation.
Abscesses
Anabscessshowsanannularenhancement,andgasinclusionsinside
willproveit.Diffuseperitonitisisnoteasytodiagnose,buthelpfulsigns
include fluid collections between intestinal loops and in the pouch of
Douglas,andathickenedbaseofthesmallbowelmesentery.
Retroperitoneum,bigvesselsandabdominalwall
Lookatthelumenoftheaortaandthepelvicvesselsinordertofinda
ruptured aneurysm. Look for free gas or a collection suggesting an
abscessduetoretroperitonealperforationofaviscussuchasthecolon
or duodenum. Looking at the abdominal wall, try to find pathological
changes like subcutaneous abscesses, rectus sheath hematomas or
abdominalwallhernias.
Andbenicetoyourradiologists…theycanbeyourbestfriends!
FinalwordsfromMoshe…
Unfortunatelyorfortunately—dependingonone’sviewpoint—inthe
USA,whereIpractice,thedecisionaboutwhomandwhentoscanisno
longer in our surgical hands.Aren’t welosing control?Thefactof the
matteristhatmost(ifnotall)patientshavealreadyundergoneaCT
scanbeforewesurgeonsarecalledupontoassessthem.Typically,
such scans are ordered by emergency room physicians or other
specialistsbefore consultingthesurgeon. Inmost hospitalsinthe USA,
eventhetinyruralones,high-techCTimagesaremucheasiertoobtain
thanagourmet meal or even a cup of real coffee.And radiologists are
alwaysreadilyavailable to interpret the images online. No wonder then
thatphysiciansandalliedprovidersconfrontedwithwhattheyperceiveto
be an acute abdomen feel compelled to get a CT which is as easily
procuredasjunkfood.Thegeneralruleis:themoreinsecureoneis—
themoreimaging(andothertesting)isobtained…
Is this practice of (almost) routine CT scanning, imposed on us by
others,andimpossibleforustomodifyorreverse,‘good’or‘bad’forour
patients? It is very difficult, if not impossible, to prove scientifically that
this increased use of CT scanning isbeneficial overall.But what about
theindividualpatient?
Luckily,gonearethedayswhentheacuteabdomenrepresenteda
totally blackbox — days I remember well from my training — when
peritonealsigns on examination mandated alaparotomy— which often
provedtobe‘negative’or ‘non-therapeutic’, and therefore unnecessary.
Thegradual introductionof CTimaging (and ultrasound)has madethat
abdominalblackboxmuchmorepenetrableandlessmysterious.Inthe
individual patient it helps us to be more selective and more
conservative; helps us to decide when not to operate, when to
choose alternative modalities (e.g. percutaneous drainage) and
guidesus tothechoice ofincision.Equally important —forthose of
uswhotakeemergencycalls,thosewhodonotyetworkinshiftsinthe
medicalfactoriesimposedonus—CTletsussleepbetterandlongerat
night.
So from the individual patient’s and surgeon’s perspective, I believe
thattheliberaluseofabdominalCTinthesettingoftheacuteabdomen
signalsapositivetrend.Therearetwocaveats:first,wehavetotryand
prevent repeated exposures to CT radiation — particularly in younger
patients,and,mostimportantly,anexperiencedabdominalsurgeonmust
betheoneinterpretingtheCTimages(togetherwiththeradiologist)and
decidinghowtoproceed.Anabdominalimagewithoutanabdominal
surgeonisonly an image — but together,thesurgeonandtheCT
represent the best modern surgical judgment — the human one
supplementedandmademoreaccurate.
“Donottreattheimagebutthepatient.Acliché?Yes.But
animportantone.”
Chapter6
Optimizingthepatient
JamesC.Rucinski
When physiology is disrupted, attempts at restoring
anatomyarefutile.
Thepreparationofthepatientforsurgerymaybeascrucial
astheoperationitself.
It’s4a.m.andyouassessyourpatientashavingan‘acuteabdomen’
—probably dueto aperforated viscus.Clearlyyourpatientneedsan
emergency laparotomy; what is left to decide is: what efforts and
how much time should be invested in his optimization before the
operation?
Optimization is a double-edged sword: wasting time trying to
‘stabilize’ an exsanguinating patient is an exercise in futility, for he will
die.Conversely,rushing to surgery with a hypovolemicpatientsuffering
fromintestinalobstructionisarecipefordisaster.
Theissuestobediscussedarehighlightedbelow.
Whypre-operativeoptimizationatall?
Whatarethegoalsofoptimization?
Whoneedsoptimization?
Howtodoit?
Whyispre-operativeoptimizationnecessary?
Simply, because volume-depleted patients do not tolerate
anesthesiaandanoperation.Theinductionofgeneralanesthesiaand
muscle relaxation causes systemic vasodilatation, depressing the
compensatory anti-shock physiologic mechanisms. On opening the
abdomen,intraperitonealpressuresuddenlydeclines,allowingpoolingof
bloodinthe venous system, that, in turn,decreasesvenousreturn and
thusreducescardiacoutput.Anemergencylaparotomy in an under-
resuscitated patient may result in cardiac arrest even before the
operation is started.In addition, the intra-operative fluid requirements
are unpredictable: do you wantto start with a volume-depletedpatient,
havingtochaseyourtail?
Remember: Operating on a poorly resuscitated patient is like driving (under the
influenceofalcohol)asnowmobileonthinice!
Whatarethegoalsofoptimization?
Patientsawaitinganemergencylaparotomyneedoptimization fortwo
main reasons: hypovolemia or sepsis. Both conditions cause underperfusion of the tissues and both are treated initially with volume
expansion.Thechiefgoalofpre-operativeoptimizationistoimprove
the delivery of oxygen to the cells. There is a direct relationship
between cellular hypoxia and subsequent cellular dysfunction, SIRS,
organfailureandadverseoutcome.
Insicksurgicalpatients,unlikemedicalones,optimizationmeans
VOLUMEandmorevolume—alotofi.v.fluids.(However,this,aswill
be emphasized below, is not true in actively bleeding patients; here
optimizationmeansimmediatecontrolofthehemorrhage—anduntilthis
is achieved you should restrict fluids and keep the patient moderately
hypotensive.)
Whoneedsoptimization?
Surgical patients often look ‘sick’. The appearance of the patient
usually gives an important first impression even before factoring in
tachycardia, tachypnea, hypotension, mental confusion, and poor
peripheralperfusion.Solookatyourpatient—notonlyathisserum
lactatelevel!
Only basic laboratory studies are necessary. Hemoconcentration,
reflectedinanabnormallyhighhemoglobinandhematocrit,implieseither
severedehydrationorextracellular‘thirdspace’fluidsequestration.Urine
analysis showing a high specific gravity (>1.039) provides similar
information. Electrolyte imbalance and associated prerenal azotemia
(withabloodureanitrogen[BUN]-to-creatinineratioof>20:1)againimply
volume depletion. Arterial blood gas measurement gives critical
informationregardingrespiratoryfunctionandtissueperfusion.Notethat
intheemergencysurgicalpatient,metabolicacidosisalmostalways
means lactic acidosis — associated with inadequate tissue
oxygenation and anaerobic metabolism at the cellular level. Other
causesofmetabolicacidosissuchasrenalfailure,diabeticketoacidosis
or toxic poisoning arepossible but extremely unlikely. A basedeficit of
morethan6 (BEless thanminus6)isa markerof significantmetabolic
acidosis and adverse prognosis and indicates a need for aggressive
resuscitation.Ofcourse,theERdocorthenurse-hospitalisthasalready
measuredtheserumlactate...
All patients with any degree of the above physiological
abnormalities need optimization. Naturally, the magnitude of your
effortsshouldcorrelatewiththeseverityofthedisturbances.
Measurementoftheseverityofillness
Anexperiencedsurgeoncan ‘eye-ball’hisorherpatientand estimate
howsicktheyarebyassessingthe“gleaminhiseyeandthestrengthof
thegrip…”.Buttermssuchas‘verysick’,‘criticallyill’or‘moribund’mean
different things to different people. We recommend therefore that you
become familiar with a universal physiological scoring system which
givesanobjectivemeasureof‘sickness’.Onescoringsystem,whichhas
beenvalidatedinmostemergency surgicalsituations, isthe APACHEII
(Acute Physiological And Chronic HealthEvaluation) — use one ofthe
online calculators, e.g:
http://clincalc.com/icumortality/apacheii.aspx#Mortality. It measures the
physiological consequences of acute disease while taking into
consideration the patient’s pre-morbid state and age. The scores are
easily measured from readily available basic clinical and laboratory
variablesandcorrelatewithapredictionofmorbidityandmortality.
An adjunctive method of assessing pre-operative risk is now
available through the American College of Surgeons NSQIP
(National Surgical Quality Improvement Program) Risk Calculator. The
calculator is an online tool that can be used to determine an
individualizedrisk profileforyour specificpatient.The calculatorutilizes
outcomedatafromallof thehospitals thatparticipateinthe Programin
order to allow a statistical prediction of various outcomes (such as
surgicalsite infection,respiratory infectionor death)associated withthe
characteristics of your patient. The tool is available at:
www.riskcalculator.facs.org.
HowIdoit?( Figure6.1)
Principles of optimization: air goes in andout; blood goes
‘roundand‘round;oxygenisgood.
Figure6.1.“Letmeoptimizeyou…”
Despitethehigh-techintensivecareunit(ICU)environment,whichmay
or may not be available to you, optimization of the surgical patient is
simple.Itcanbeaccomplishedanywhereandrequiresminimalfacilities.
Allyouwantisbetteroxygendelivery,i.e.increasedoxygenationof
arterialbloodandenhancedtissueperfusion.Youdonotneedafive-
starICUbutyoudohavetostickaroundwiththepatient!Writingorders
and going to bed (until the operation) will unnecessarily prolong the
optimizationanddelaytheoperation.Sostaywiththepatient,monitor
hisprogressandbetheretodecidewhenenoughisenough.
Oxygenation
Hypoxianotonlystopsthemotor,itwreckstheengine!
Any patient who requires optimization should at least receive
oxygenbymask.Look atthe patientand hispulseoximetryorarterial
blood gases; evidence of severe hypoventilation or poor oxygenation
may be an indication for endotracheal intubation and mechanical
ventilation. Do not temporize, the patient will need intubation
anyway,sowhynotnow?Remember,painanddistensionassociated
with any abdominal catastrophe impede ventilation. Effective analgesia
impairsventilationstillfurther.Ifanasogastric(NG)tubeisnotalreadyin
situ this may be the time to insert one. The advantages of NG tube
insertionbeforeintubationaretodecompressthedistendedstomachand
reducetherisk of aspiration during the procedure. The disadvantageis
that the presence of a tube through the cricopharyngeus may allow
regurgitationduringrapidsequenceinductionofanesthesia.
Restorationofvolume
Themajorcauseofshockisdecreasedcirculatoryvolume.
Replacebodyfluidsbythebestmeansathand.
AlfredBlalock
Nowafteryourpatientiswelloxygenatedyoumustseetoitthat
theoxygen arrives where it isneeded, by restoringblood volume.
Thisis accomplishedby an intravenousinfusionofcrystalloidssuchas
normalsalineorRinger’slactate.Forgetaboutthemuchmoreexpensive
colloids such as fresh frozen plasma, albumin or solutions containing
syntheticorganic macromolecules such ashetastarchor low-molecularweightdextran;their theoreticaladvantages haveneverbeentranslated
intobetterresults—theoppositeistrue!Hypertonicsalineresuscitation
may theoretically be advantageous but it remains an investigational
therapyat present.(It hasbeen experimentalsince wefinishedmedical
school…).Bloodandbloodproductsaregivenifnecessary,asdiscussed
below.
How much crystalloid to infuse? An old rule of thumb was that the
hypovolemic surgical patient needs more volume than you think they
need,andmuchmorethanthenursingstaffthinktheyneed.Butthisrule
isnowoutdated—seetheeditorialcommentattheendofthechapter.
Weassume that your patient already has a large-bore i.v. cannula in
situ—sojusthookituptothesolutionandopenthevalveandletitrun!
Yourunina literandhang upanother. Buthowmuchisenough?At
thisstageyouneedtoassesstheeffectivenessofwhatyoudo.
Measurementofeffectivenessoftreatment
Again, the principal goal of non-operative treatment in the
emergency surgical patient is the restoration of adequate tissue
oxygenation!This endpoint isrecognized byphysical examination
and measurement of urinary output, in conjunction with the
information provided by selective invasive monitoring and
laboratorystudies.
With fluid resuscitation one hopes to see improvement of tissue
oxygenationbynormalizationofvitalsignsandimprovementinthevisible
peripheral circulation. Resolution of hypotension, mental confusion,
tachypneaandtachycardiamaybeseeneitherpartiallyorfully.Postural
hypotensionreflects a significant deficit in the circulating blood volume.
Rememberthattheusualresponsetoachangeinpositionfromsupineto
uprightisanincreaseinthesystolicbloodpressure—awideningofthe
pulsepressure.Consequently,ifanarrowingofthepulsepressureis
seenwhenthepatientsitsupthenposturalhypotensionispresent.
With fluid resuscitation, mottling of the skin and the palpable
temperature of the fingers and toes may improve. Capillary refill is a
clinical test that observes the peripheral circulation in the nail bed. The
nail bed blanches when pressed and should return to its normal pink
color in less than 2 seconds. Fluid resuscitation aims to improve this
measureoftheperipheralcirculationaswell.
Urineoutput
Ventilate,perfuse,andpissisallthatitisabout!
MattOliver
A Foley urinary bladder catheter is essential in any patient requiring optimization. It
allows an accurate, if indirect, measurement of tissue perfusion and adequacy of fluid
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