1. DENGUE:
Types
There are twomaintypesof volume expanders;crystalloidsandcolloids.Crystalloidsare aqueous
solutionsof mineral saltsorotherwater-soluble molecules.Colloidscontainlargerinsoluble molecules,
such as gelatin;blooditself isa colloid.
[edit] Colloids
Colloidspreserve ahighcolloidosmoticpressure inthe blood,while,onthe otherhand,thisparameter
isdecreasedbycrystalloidsdue tohemodilution.[1] Therefore,theyshouldtheoreticallypreferentially
increase the intravascularvolume,whereascrystalloidsalsoincrease the interstitialvolume and
intracellularvolume.However,there isstillcontroversyastothe actual difference inefficacydue tothis
difference inaction.[1] Anotherdifference isthatcrystalloidsgenerallyare muchcheaperthan
colloids.[1]
[edit] Hydroxyethylstarch
Main article:Hydroxyethyl starch
Hydroxyethyl starch(HES/HAES,commontrade names:Hespan,Voluven) isone of the mostfrequently
usedcolloids.Anintravenoussolutionof hydroxyethyl starchisusedtopreventshockfollowingsevere
bloodlosscausedbytrauma, surgery,orsome otherproblem.Itincreasesthe bloodvolume,allowing
redbloodcellstocontinue todeliveroxygentothe body.
[edit] Crystalloids
The most commonlyusedcrystalloidfluidisnormal saline,asolutionof sodiumchloride at0.9%
concentration,whichisclose tothe concentrationinthe blood(isotonic).Ringer'slactate orRinger's
acetate isanotherisotonicsolutionoftenusedforlarge-volume fluidreplacement.A solutionof 5%
dextrose inwater,sometimescalledD5W,isoftenusedinsteadif the patientisatriskforhavinglow
bloodsugaror highsodium.The choice of fluidsmayalsodependonthe chemical propertiesof the
medicationsbeinggiven.
Intravenousfluidsmustalwaysbe sterile.

2. [edit] Ringer'ssolution
Lactated Ringer'ssolutioncontains28mmol/Llactate,4 mmol/LK+ and 1.5 mmol/LCa2+. It isvery
similar- thoughnot identical to - Hartmann'sSolution,the ionicconcentrationsof whichdiffer.
Ringer'sacetate consistsof 28 mmol/Lacetate,4 mmol/LK+ and 1.5 mmol/LCa2+.
Normal saline
Main article:Saline (medicine)
Normal saline (NS) isthe commonly-usedtermforasolutionof 0.91% w/vof NaCl,about300
mOsm/L.[2] Lesscommonly,thissolutionisreferredtoasphysiological salineorisotonicsaline,neither
of whichistechnicallyaccurate.NSisusedfrequentlyinintravenousdrips(IVs)forpatientswhocannot
take fluidsorallyandhave developedorare in dangerof developing dehydrationorhypovolemia.NSis
typicallythe firstfluidusedwhenhypovolemiaissevereenoughtothreatenthe adequacyof blood
circulation,andhaslongbeenbelievedtobe the safestfluidtogive quicklyinlarge volumes.However,it
isnow knownthatrapidinfusionof NScan cause metabolicacidosis.[3]
[edit] Glucose (dextrose)
Intravenoussugarsolutions,suchaswithglucose (alsocalleddextrose),have the advantage of providing
some energy,andmaytherebyprovide the entireorpart of the energycomponentof parenteral
nutrition.
Typesof glucose/dextrose include:
D5W (5% dextrose inwater),whichconsistsof 278 mmol/Ldextrose
D5NS (5% dextrose innormal saline),which,inaddition,containsnormal saline.

3. [edit] Comparisontable
Compositionof commoncrystalloidsolutionsSolution OtherName
[Na+](mmol/L) [Cl-](mmol/L) [Glucose](mmol/L) [Glucose](mg/dl)
D5W 5% Dextrose 0 0 278 5000
2/3D & 1/3S 3.3% Dextrose /0.3% saline 51 51 185 3333
Half-normal saline 0.45% NaCl 77 77 0 0
Normal saline 0.9% NaCl 154 154 0 0
Ringer'slactate Lactated Ringer 130 109 0 0
D5NS 5% Dextrose,Normal Saline 154 154 278 5000
Effectof addingone litre Solution
Change inECF Change inICF
D5W 333 mL 667 mL
2/3D & 1/3S 556 mL 444 mL
Half-normal saline 667 mL 333 mL
Normal saline 1000 mL 0 mL
Ringer'slactate 900 mL 100 mL
Supportive:
Patientsrequire emergencytreatmentandurgentreferral whentheyare inthe critical
phase of disease,i.e.whentheyhave:
– severe plasmaleakageleadingtodengue shockand/orfluidaccumulation

4. withrespiratorydistress;
– severe haemorrhages;
– severe organimpairment(hepaticdamage,renal impairment,cardiomyopathy,
encephalopathyorencephalitis).
All patientswithsevere dengue shouldbe admittedtoahospital withaccessto
intensivecare facilitiesandbloodtransfusion.Judiciousintravenousfluidresuscitation
isthe essentialandusuallysole interventionrequired.The crystalloid solutionshould
be isotonicandthe volume justsufficienttomaintainaneffectivecirculationduringthe
periodof plasmaleakage.Plasmalossesshouldbe replacedimmediatelyandrapidly
withisotoniccrystalloidsolutionor,inthe case of hypotensive shock,colloidsolutions
(Textbox M).If possible,obtainhaematocritlevelsbefore andafterfluidresuscitation.
There shouldbe continuedreplacementof furtherplasmalossestomaintaineffective
circulationfor24–48 hours.
Bloodtransfusionshouldbe givenonlyincaseswithsuspected/severebleeding.
Treatmentof shock
The action planfor treatingpatientswithcompensatedshockisasfollows(TextboxesD
and N,Figure 2.2):
Start intravenousfluidresuscitationwithisotoniccrystalloidsolutions at5–10 ml/kg/houroverone
hour.Thenreassessthe patient’scondition(vitalsigns,capillaryrefill time,haematocrit,urine output).
The nextstepsdependonthe situation.
• If the patient’sconditionimproves,intravenousfluidsshouldbe graduallyreducedto5–7 ml/kg/hrfor
1–2 hours,thento3–5 ml/kg/hrfor2–4 hours,thento 2–3 ml/kg/hr,andthenfurtherdependingon
haemodynamicstatus,whichcanbe maintainedforupto24–48 hours.(See textboxesHand J fora
more appropriate estimate of the normal maintenance requirementbasedonideal bodyweight).

5. • If vital signsare still unstable (i.e.shockpersists),checkthe haematocritafterthe firstbolus.If the
haematocritincreasesorisstill high(>50%),repeatasecondbolusof crystalloid solutionat10–20
ml/kg/hrforone hour.Afterthissecondbolus,if there isimprovement,reduce the rate to7–10 ml/
kg/hrfor 1–2 hours,andthencontinue toreduce as above.If haematocritdecreasescomparedtothe
initial reference haematocrit(<40%inchildrenandadultfemales,<45% in adultmales),thisindicates
bleedingandthe needtocross-matchand transfuse bloodassoonas possible (see treatmentfor
haemorrhagiccomplications).
• Furtherbolusesof crystalloidorcolloidal solutionsmayneedtobe given duringthe next24–48 hours.
A decrease inhaematocrittogetherwithunstablevital signs(particularlynarrowingof the pulse
pressure,tachycardia,metabolicacidosis,poorurine output) indicatesmajorhaemorrhage andthe need
for urgentbloodtransfusion.Yeta decrease inhaematocrit togetherwithstable haemodynamicstatus
and adequate urine outputindicates haemodilutionand/orreabsorptionof extravasatedfluids,soin
thiscase intravenous fluidsmustbe discontinuedimmediatelytoavoidpulmonaryoedema.
Treatmentof haemorrhagiccomplications
Mucosal bleedingmayoccurin anypatientwithdengue but,if the patientremainsstable withfluid
resuscitation/replacement,itshouldbe consideredasminor.The bleeding usuallyimprovesrapidly
duringthe recoveryphase.Inpatientswithprofoundthrombocytopaenia,ensure strictbedrestand
protectfrom traumato reduce the risk of bleeding.Donotgive intramuscularinjectionstoavoid
haematoma.Itshouldbe notedthatprophylacticplatelettransfusionsforseverethrombocytopaeniain
otherwise haemodynamicallystable patientshave notbeenshowntobe effectiveandare notnecessary
Severe bleedingcanbe recognizedby: – persistentand/orsevere overtbleedinginthe presence of
unstable haemodynamicstatus,regardlessof the haematocritlevel;
– a decrease inhaematocritafterfluidresuscitationtogetherwithunstablehaemodynamicstatus;
– refractoryshockthat failstorespondto consecutive fluidresuscitation of 40-60 ml/kg;
– hypotensive shockwithlow/normalhaematocritbefore fluidresuscitation;
– persistentorworseningmetabolicacidosis±a well-maintainedsystolicblood
pressure,especiallyinthose withsevere abdominaltendernessanddistension.

6. Considerrepeatingthe bloodtransfusionif there isfurtherbloodlossorno appropriate rise in
haematocritafterbloodtransfusion.There islittleevidence to supportthe practice of transfusing
plateletconcentratesand/orfresh-frozenplasmaforseverebleeding.Itisbeingpractisedwhenmassive
bleedingcannot be managedwithjustfreshwhole blood/fresh-packedcells,butitmayexacerbate the
fluidoverload.
Causesof fluidoverloadare:
– excessive and/ortoorapidintravenousfluids;
– incorrectuse of hypotonicratherthanisotoniccrystalloidsolutions;
– inappropriate use of large volumesof intravenousfluidsinpatientswithunrecognizedsevere
bleeding;
– inappropriate transfusionof fresh-frozenplasma,plateletconcentratesandcryoprecipitates;
– continuationof intravenousfluidsafterplasmaleakage hasresolved(24–48hours from
defervescence);
– co-morbidconditionssuchascongenital orischaemicheartdisease,chroniclungandrenal diseases.
Early clinical featuresof fluidoverloadare:
– respiratorydistress,difficultyinbreathing;
– rapidbreathing;
– chestwall in-drawing;
– wheezing(ratherthancrepitations);
– large pleural effusions;
– tense ascites;
– increasedjugularvenouspressure(JVP).
Late clinical featuresare:
– pulmonaryoedema(coughwithpinkorfrothysputum± crepitations,cyanosis);
– irreversibleshock(heartfailure,oftenincombinationwithongoing
hypovolaemia).

7. Patientswhoremaininshockwithlowornormal haematocritlevelsbutshow signsof fluid overload
may have occulthaemorrhage.Furtherinfusionof large volumesof intravenousfluidswillleadonlytoa
poor outcome.
Othercomplicationsof dengue
Both hyperglycaemiaandhypoglycaemiamayoccur,eveninthe absence of diabetesmellitusand/or
hypoglycaemicagents.Electrolyte andacid-baseimbalancesare alsocommonobservationsinsevere
dengue andare probablyrelatedtogastrointestinal lossesthroughvomitinganddiarrhoeaortothe use
of hypotonicsolutionsforresuscitationandcorrection of dehydration.Hyponatraemia,hypokalaemia,
hyperkalaemia,serumcalciumimbalancesandmetabolicacidosis(sodiumbicarbonate formetabolic
acidosisisnotrecommendedforpH≥ 7.15) can occur. One shouldalsobe alertforco-infectionsand
nosocomial infections.
Choice of intravenousfluidsforresuscitation
Basedon the three randomizedcontrolledtrialscomparingthe differenttypesof fluidresuscitation
regime in
dengue shockinchildren,there isnoclearadvantage tothe use of colloidsovercrystalloidsintermsof
the overall
outcome.However,colloidsmaybe the preferredchoice if the bloodpressure hastobe restored
urgently,i.e.in
those withpulse pressure lessthan10 mm Hg. Colloidshave beenshowntorestore the cardiacindex
and reduce
the level of haematocritfasterthancrystalloidsinpatientswithintractableshock(18–20).
An ideal physiological fluidisone thatresemblesthe extracellularandintracellularfluidscompartments
closely. However,the availablefluidshave theirown limitationswhenusedinlarge quantities.
Therefore itisadvisable to understandthe limitationsof these solutionstoavoidtheirrespective
complications.
Crystalloids
0.9% saline (“normal”saline)
Normal plasmachloride rangesfrom95 to 105 mmol/L. 0.9% Saline isasuitable optionforinitialfluid
resuscitation,butrepeatedlarge volumesof 0.9% saline mayleadtohyperchloraemicacidosis.
Hyperchloraemicacidosismayaggravate orbe confusedwithlacticacidosisfromprolongedshock.
Monitoringthe chloride andlactate levelswillhelptoidentifythisproblem.Whenserumchloride level
exceedsthe normal range,itis advisable tochange tootheralternativessuchasRinger’sLactate.

8. Ringer’sLactate
Ringer’sLactate has lowersodium(131mmol/L) andchloride (115 mmol/L) contentsandan osmolality
of273 mOsm/L.It maynot be suitable forresuscitationof patientswithsevere hyponatremia.However,
it isa suitable solutionafter0.9Saline hasbeengivenandthe serumchloride level hasexceededthe
normal range. Ringer’sLactate shouldprobablybe avoidedinliverfailure andinpatientstaking
metforminwhere lactate metabolismmaybe impaired.
Colloids
The typesof colloidsare gelatin-based,dextran-basedandstarch-basedsolutions.One of the biggest
concernsregardingtheiruse istheirimpactoncoagulation.Theoretically,dextransbindtovon
Willebrandfactor/FactorVIIIcomplex andimpaircoagulationthe most.However,thiswasnotobserved
to have clinical significance influidresuscitationindengueshock.Of all the colloids,gelatine hasthe
leasteffectoncoagulationbutthe highestriskof allergicreactions.Allergicreactionssuchasfever,chills
and rigorshave alsobeenobservedinDextran70.Dextran40 can potentiallycause anosmoticrenal
injuryinhypovolaemicpatients.