Aromatherapy for treatment of postoperative nausea and vomiting

44 Pages·2012·0.46 MB·English

Aromatherapy for treatment of postoperative nausea and
vomiting (Review)
Hines S, Steels E, Chang A, Gibbons K
ThisisareprintofaCochranereview,preparedandmaintainedbyTheCochraneCollaborationandpublishedinTheCochraneLibrary
2012,Issue4
http://www.thecochranelibrary.com
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review)
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SUMMARYOFFINDINGSFORTHEMAINCOMPARISON . . . . . . . . . . . . . . . . . . . 2
BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
ADDITIONALSUMMARYOFFINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . 14
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
ADDITIONALTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
DIFFERENCESBETWEENPROTOCOLANDREVIEW . . . . . . . . . . . . . . . . . . . . . 42
INDEXTERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) i
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
[InterventionReview]
Aromatherapy for treatment of postoperative nausea and
vomiting
SoniaHines1,ElizabethSteels2,AnneChang1,KristenGibbons3
1MaterNursingResearchCentre,QueenslandCentreforEvidence-BasedNursing&Midwifery,ACollaboratingCentreoftheJoanna
BriggsInstitute,SouthBrisbane,Australia.2FacultyofHealthSciences,AustralianCollegeofNaturalMedicine,Brisbane,Australia.
3ClinicalResearchSupportUnit,MaterMedicalResearchInstitute,SouthBrisbane,Australia
Contactaddress:SoniaHines,MaterNursingResearchCentre,QueenslandCentreforEvidence-BasedNursing&Midwifery,ACol-
laboratingCentreoftheJoannaBriggsInstitute,MaterHealthServices„LevelOne,QuartersBuilding,AnnerleyRd,Woolloongabba,
SouthBrisbane,Queensland,4102,[email protected]@optusnet.com.au.
Editorialgroup:CochraneAnaesthesiaGroup.
Publicationstatusanddate:New,publishedinIssue4,2012.
Reviewcontentassessedasup-to-date: 2August2011.
Citation: Hines S, Steels E, Chang A, Gibbons K. Aromatherapy for treatment of postoperative nausea and vomiting. Cochrane
DatabaseofSystematicReviews2012,Issue4.Art.No.:CD007598.DOI:10.1002/14651858.CD007598.pub2.
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
ABSTRACT
Background
Postoperative nausea andvomitingisacommon andunpleasantphenomenonandcurrenttherapiesarenotalwayseffectivefor all
patients.Aromatherapyhasbeensuggestedasapossibleadditiontotheavailabletreatmentstrategies.
Objectives
Thisreviewsoughttoestablishwhateffecttheuseofaromatherapyhasontheseverityanddurationofestablishedpostoperativenausea
andvomitingandwhetheraromatherapycanbeusedwithsafetyandclinicaleffectivenesscomparabletostandardpharmacological
treatments.
Searchmethods
We searchedthe Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3); MEDLINE;
EMBASE;CINAHL;CAMonPubMed;Meditext;LILACS;andISIWebofScienceaswellasgreyliteraturesourcesandthereference
listsofretrievedarticles.WeconducteddatabasesearchesuptoAugust2011.
Selectioncriteria
We included all randomized controlled trials (RCTs) and controlled clinical trials (CCTs) where aromatherapy was used to treat
postoperativenauseaandvomiting.Interventionswerealltypesofaromatherapy.Aromatherapywasdefinedastheinhalationofthe
vapoursofanysubstanceforthepurposesofatherapeuticbenefit.Primaryoutcomesweretheseverityanddurationofpostoperative
nauseaandvomiting.Secondaryoutcomeswereadversereactions,useofrescueanti-emeticsandpatientsatisfactionwithtreatment.
Datacollectionandanalysis
Tworeviewauthorsassessedriskofbiasintheincludedstudiesandextracteddata.Asalloutcomesanalysedweredichotomous,we
usedafixed-effectmodelandcalculatedrelativerisk(RR)withassociated95%confidenceinterval(95%CI).
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 1
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Mainresults
ThenineincludedstudiescomprisedsixRCTsandthreeCCTswithatotalof402participants.Themeanageandrangedataforall
participantswerenotreportedforallstudies.ThemethodofrandomizationinfourofthesixincludedRCTswasexplicitlystatedand
wasadequate.Incompletereportingofdataaffectedthecompletenessoftheanalysis.Comparedwithplacebo,isopropylalcoholvapour
inhalationwaseffectiveinreducingtheproportionofparticipantsrequiringrescueanti-emetics(RR0.30,95%CI0.09to1.00,P
=0.05).However,comparedwithstandardanti-emetictreatment,isopropylalcoholwasnoteffectiveinreducingtheproportionof
participantsrequiringrescueanti-emetics(RR0.66,95%CI0.39to1.13,P=0.13)exceptwhenthedatafromapossiblyconfounded
studywereincluded(RR0.66,95%CI0.45to0.98,P=0.04).Wherestudiesreporteddataonpatientsatisfactionwitharomatherapy,
therewerenostatisticallysignificantdifferencesbetweenthegroups(RR1.12,95%CI0.62to2.03,P=0.71).
Authors’conclusions
Isopropylalcoholwasmoreeffectivethansalineplaceboforreducingpostoperativenauseaandvomitingbutlesseffectivethanstandard
anti-emeticdrugs.Thereiscurrentlynoreliableevidencefortheuseofpeppermintoil.
PLAIN LANGUAGE SUMMARY
Aromatherapyfortreatingpostoperativenauseaandvomiting
Postoperative nausea and vomiting (PONV)is a common and unpleasant side effect of surgery, with 20% to 30% of all patients
sufferingmoderatetoseverenauseaandvomitingfollowinggeneralanaesthesiausingvolatileagents(inhaledanaesthesia).Nauseais
anabdominal discomfortorqueasinessthatmaybeaccompaniedbyvomiting(theforcefulexpulsionofstomachcontentsthrough
the mouth). Current drug treatments may not always work effectivelyor they may have unpleasant adverse effects. Aromatherapy
is sometimes recommended for treating nausea and vomiting, though currently there is not sufficient evidence that it is effective.
Aromatherapyusesinhalationofthevapourofessentialoilsorothersubstancestotreatoralleviatephysicalandemotionalsymptoms.
WeexaminedninestudiesofaromatherapyforPONV,withatotalof402participants.Sixstudiesofthebriefinhalationofisopropyl
alcoholvapoursshowedthatitcanhavesomeeffectinreducingpostoperativenauseaandvomiting;howeveritseemstobelesseffective
thanstandarddrugtreatments.Therewasamoderateriskofbiasduetothedesignofsomeofthestudies.Isopropylalcoholisalso
knownasrubbingalcoholandiscommonlyfoundinthetypeof’prep-pad’usedtocleanskinpriortoinjection.Thereiscurrently
noreliableevidencetosupporttheuseofotheraromatherapiessuchaspeppermintoiltotreatpostoperativenauseaandvomiting.No
includedstudiesreportedanyadverseeffectsfromthearomatherapiesused.
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 2
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
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SUMMARYOFFINDINGSFORTHEMAINCOMPARISON[Explanati Isopropylalcoholcomparedtostandardtreatmentfortreatmentofpostoperativenauseaandvomiting Patientorpopulation:patientswithtreatmentofpostoperativenauseaandvomitingSettings:Post-anaesthesiaCareAreasIntervention:IsopropylalcoholComparison:Standardtreatment OutcomesIllustrativecomparativerisks*(95%CI)RelativeeffectNoofParticipants(95%CI)(studies) AssumedriskCorrespondingrisk StandardtreatmentIsopropylalcohol 1RequirementforrescueStudypopulationRR0.66215anti-emetics(0.45to0.98)(4studies)392per1000259per1000(176to384) 1Mediumriskpopulation 275per1000182per1000(124to270) 4AdverseeffectsSeecommentSeecommentNotestimable0(0) assumedriskcorrespondi*Thebasisforthe(e.g.themediancontrolgroupriskacrossstudies)isprovidedinfootnotes.Therelativeeffectassumedriskinthecomparisongroupandtheoftheintervention(andits95%CI).CI:RR:Confidenceinterval;Riskratio; GRADEWorkingGroupgradesofevidenceHighquality:Furtherresearchisveryunlikelytochangeourconfidenceintheestimateofeffect.Moderatequality:FurtherresearchislikelytohaveanimportantimpactonourconfidenceintheestimateofeffectandmaychanLowquality:FurtherresearchisverylikelytohaveanimportantimpactonourconfidenceintheestimateofeffectandislikelytoVerylowquality:Weareveryuncertainabouttheestimate.
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 3
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
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Calculatedusingcontrolgroupresults.StudybyMerritt(2002)wasnotadequatelTotalnumberofeventsislessthan300.Nodataonthisoutcome. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 4
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
BACKGROUND
and acceptable than the ingestion or injection of conventional
Aromatherapyhasbeenrecommendedforthetreatmentofpost-
drugs(Eisenberg1998).Asignificantnumberofhealthconsumers
operativenauseaandvomiting(PONV)(Bone1990;Maddocks-
alreadyself-prescribeand administer aromatherapy productsfor
Jennings 2004). It is known that this therapy is inexpensive,
various common conditions, or consult qualifiedor unqualified
non-invasiveandgenerallyhaslowlevelsofadverseeffects(Price
aromatherapypractitionersforhealthadvice(Eisenberg1998).
2007), particularly in comparison to standard pharmacological
treatments.Whatisnotknowniswhethertheclinicaleffectiveness In particular, ginger, fennel and peppermint, as either a topical
justifiesitsuse. application (massage or a compress) or via inhalation, are well-
knowntreatments(Price2007).Theeffectivenessoftheoilsmay
Nauseaisanabdominaldiscomfortorqueasinessthatmaybeac-
beduetoanalgesicandanti-emeticproperties(withpeppermint
companiedbyvomiting(theforcefulexpulsionofstomachcon-
oilandginger oil)or anti-spasmodic properties(peppermintoil
tents through the mouth). Postoperative nausea and vomiting
and fenneloil). Peppermintoil is wellrecognized for itsrolein
(PONV)isoneofthemostcommonadversereactionstosurgery
digestion disorders, dueprincipally tothepresenceof menthols
andalltypesofanaesthesia,with20%to30%ofallpatientssuf-
(seeAppendix1fordetails).Therehavebeenanumberofstudies
feringmoderatetoseverenauseaandvomitingfollowinggeneral
conductedusinggingeroil,withconflictingresults(Arfeen1995;
anaesthesiausingvolatileagents(Watcha1992).
Bone1990;Meyer1995;Phillips1993).Isopropylalcoholissaid
Aside fromthedistressing nature of PONVitself, asa resultof tobeatraditionalnausearemedyfromSouthAmerica(Anderson
PONVpatientsmayexperiencesuchadverseeffectsaswoundde- 2004; Mamaril 2006; Spencer 2004), however none of the pa-
hiscence,dehydration,electrolyteimbalancesoraspirationpneu- pers citing this provided a primary source for this information.
monia(Kovac2000).Otheradverseeffectsmayincludeincreased Isopropylalcohol,alsoknownasrubbingalcoholandcommonly
patientbeddays,unplannedreadmissions(particularlyinthecase foundinthetypeof’prep-pad’usedtocleanskinpriortoinjec-
of day surgery) (Kovac2000)and decreasedpatient satisfaction tion,doesappeartobewidelyusedinsomepostanaesthesiacare
(Myles2000).Certainpatientsaremorepre-disposedthanothers unitstotreatPONV(Cotton2007;Merritt2002;Pellegrini2009;
to suffering fromPONVand risk factors include being female, Spencer 2004; Wang 1999; Winston 2003). It is thesubject of
a non-smoker, having a history of PONV or perioperative opi- severaleffectivenessstudies.
oidexposure(Koivuranta1997).Alongwithpostoperativepain,
PONVisoneofthemainconcernsofpatientsfacingsurgeryand
oneofthemaincausesofpatientdissatisfaction(Myles2000). OBJECTIVES
Currenttreatmentinvolveseithertheprophylacticorsymptomatic
Toestablish:
administration of anti-emetic drugs such as droperidol, meto-
clopramide or 5-HT3 receptorantagonists such asondansetron
• whateffecttheuseofaromatherapyhasontheseverityof
(White1999).Despiteawiderangeofavailabletreatments,some
establishedpostoperativenauseaandvomiting;
patients will still experience PONV invarying levelsof severity
(Kazemi-Kjellberg2001).Clinically,theseverityofPONVisgen- • whateffecttheuseofaromatherapyhasonthedurationof
erallymeasuredbymeansofavisualanaloguescale(VAS),which establishedpostoperativenauseaandvomiting;
providesavisual representationofthepatient’scondition overa
• whetheraromatherapycanbeusedwithsafetyandclinical
numericalrange(forexample0to5),orverbaldescriptivescales
effectivenesscomparabletostandardpharmacologicaltreatments
(for example no nausea, some nausea, very nauseated, retching,
totreatestablishedpostoperativenauseaandvomiting.
vomiting)(Boogaerts2000).Theeffectivenessofthevariousdrugs
for PONV has already been the subject of a Cochrane review
(Carlisle2006),howevernoexistingreviewhasexaminedtheef-
fectivenessofaromatherapytotreatthiscondition. METHODS
Theuseofaromatherapyoilsisrecognizedasaneffectivetreatment
for nausea in general (Chiravalle 2005; Mamaril 2006; Merritt
Criteriaforconsideringstudiesforthisreview
2002;Tate1997).Aromatherapyusestheapplicationofessential
oilsorothersubstancestoanypartofthebodyforthepurposeof
inhalationofthevapoursorabsorptionoftheoilintotheskinto
Typesofstudies
treatoralleviatephysicalandemotionalsymptoms(Price2007).
Essentialoilscanbeabsorbedthroughtheskinandmayexerta Weconsideredanyrandomizedcontrolledtrials(RCTs) orcon-
physiologicaleffectoncellularandorganfunction,althoughthis trolledclinicaltrials(CCTs)thatevaluatedtheeffectofaromather-
is not clinically understood (Ernst2001). Aromatherapyis well apyonestablishedPONV.Inordertoobtainthewidestrangeof
acceptedby many healthconsumers, whofind itmore pleasant studieswesetnodateofpublicationorlanguagelimits.
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 5
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Typesofparticipants (viaOvid)(1966to2August2011);EMBASE(1966to2August
Weconsideredallstudiesthatincludedpatients(bothadultand 2011);CINAHL(EBSCOhost)(1982to2August2011);CAM
paediatric,paediatricbeingchildrenagedlessthan18yearsofage) onPubMed(1966to2August2011);Meditext(1995to2August
havinganytypeofsurgicalprocedureundergeneralanaesthesia, 2011); LILACS (1982 to 2 August 2011); ISI Web of Science
regionalanaesthesiaorsedation,eitherashospitalinpatientsorin (1985to2August2011).
dayorambulatoryfacilities,whoweregivenaromatherapytreat- Wedevelopedaspecificstrategyforeachdatabase.Webasedeach
mentsformanagementofexistingPONV.Forthepurposesofthis searchstrategyonthatdevelopedforMEDLINE(seeAppendix
reviewweconsideredpostoperativetobetheperiodfromdayof 2fordetails).WecombinedtheMEDLINEsearchstrategywith
surgerytodischargefromhospitalor,inthecaseofdayhospital theCochranehighlysensitivesearchstrategy,phasesoneandtwo,
patients,uptothefifthpostdischargeday. ascontainedintheCochraneHandbookforSystematicReviewsof
Weexcludedstudiesofnon-surgicalpatients(medical,oncology). Interventions(Higgins2011).
Wealsoexcludedstudiesinwhicharomatherapywasusedsolely
topreventpostoperativenauseaandvomiting.
Searchingotherresources
Typesofinterventions Wealsoidentifiedtrialsbymanuallysearchingabstracts ofrele-
vantconferenceproceedingssuchastheNationalAssociationfor
Interventions of interest were those where aromatherapy prod-
HolisticAromatherapyConference.
uctswereusedbyanydeliverymethod(forexampledirectinhala-
Wecheckedthereferencelistsofrelevantarticlesandattemptedto
tion,diffusion,massageorcompress)totreatsymptomsofestab-
contactrelevanttrialauthorstoidentifyanyadditionalorongoing
lishedpostoperative nausea and vomiting, either in comparison
studies.
toaplaceboorcomparedwithstandardanti-emetictreatments.
Wealsosearchedforrelevanttrialsonspecificsites:
Aromatherapywasdefinedastheinhalationofthevapoursofany
1. CurrentControlledTrialsathttp://www.controlled-
substanceforthepurposesofatherapeuticbenefit.
trials.com;
2. ClinicalStudyResultsathttp://
Typesofoutcomemeasures www.clinicalstudyresults.org;
3. SIGLEathttp://opensigle.inist.fr/(greyliterature);
4. NewYorkLibraryofMedicineGreyLiteratureReportat
Primaryoutcomes
http://www.nyam.org/library/pages/grey_literature_report(grey
• Severityofnauseaorvomiting,orboth,post-initiationof literature);
treatmentasmeasuredbyavalidatedscaleormedicalornursing 5. NationalInstituteofClinicalStudiesathttp://
observation www.nhmrc.gov.au/nics/index.htm;
• Durationofnauseaorvomiting,orboth,post-initiationof 6. Science.govathttp://www.science.gov/browse/w_127.htm
treatmentasmeasuredbypatientreportormedicalornursing (greyliterature).
observation Wedidnotapplylanguageorpublicationdaterestrictions.
Secondaryoutcomes
• Useofpharmacologicalanti-emetics
Datacollectionandanalysis
• Anyadversereactionsorevents(commonreactionsto
aromatherapyincludeskinrashes,dyspnoea,headache,cardiac
arrhythmias,hypotension,hypertensionordizziness(Price
2007)) Selectionofstudies
• Patientsatisfactionwithtreatmentasmeasuredbya
Two authors(SHandES)independently scannedthetitlesand
validatedscale
abstracts of reports identified by the described variety of search
strategies.Weretrievedandevaluatedpotentiallyrelevantstudies,
chosenbyatleastoneauthor,infull-textversions.Weretrieved
Searchmethodsforidentificationofstudies andtranslatedanyarticleswhichappearedrelevantbutwerenot
publishedinfullinEnglish.Twoauthors(SHandES)indepen-
dentlyassessedthecongruenceoftrialswiththereview’sinclusion
Electronicsearches
criteriausingachecklistthatwasdesignedinadvanceforthatpur-
WesearchedtheCochraneCentralRegisterofControlledTrials pose (Appendix3). The thirdauthor (AC)settledany disagree-
(CENTRAL)(TheCochraneLibrary2011,Issue3);MEDLINE ments.
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 6
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Dataextractionandmanagement than40%,furtherinvestigation ofthereasonsforheterogeneity
Two authors(SHandES)independently extracteddatausing a wascarriedout.Clinicallydiversestudieswereanalysedseparately
tooldevelopedandpilotedbytheauthors(Appendix4).Were- whereverappropriate.
solvedanydisagreementsthroughconsultationwiththethirdau-
thor(AC).
Assessmentofreportingbiases
Duetothesmallnumberofstudiesincludedinthisreview,and
Assessmentofriskofbiasinincludedstudies
the small number that could be included in the meta-analyses,
WeassessedtheriskofbiasusingthetoolprovidedintheRevMan weconsidereditinappropriate togeneratefunnelplotstoassess
5.1software,basedontheworkofTheCochraneCollaboration reporting biases (Egger 1997). We did consider studies from a
(Higgins2011).Anydisagreementswereadjudicatedbythethird wide range of locations, languages and publications, which we
author(AC).Weusedthefollowingfivecriteriatoassessriskofbias believehasreducedthelikelihoodofreportingbiasesaffectingour
foreachindividualstudy:randomsequencegeneration,allocation findings(Higgins2011).
concealment, blinding, incomplete outcome data, and selective
reporting.
Datasynthesis
Measuresoftreatmenteffect We entered all trials included in the systematic review into Re-
view Manager (RevMan 5.1)andcombined dataquantitatively,
Becauseofthesubjectivenatureofnausea,measuresoftreatment
wherepossible. Wepresentedthemain outcomesinthisreview
effectwerelargelylimitedtopatient-reportedeffects,measuredby
as dichotomous variables. We calculated pooledestimates using
variousscalesincludingvisual analogue scales(VAS),verbalnu-
thefixed-effectmodel with the Mantel-Haenszelmethodas the
mericalratingscales(VRNS)anddescriptiveordinalscales(DOS).
studieswerehomogenousandsmallnumbersofeventswereob-
Weincludedothermeasuresofeffect,suchasnumberofvomiting
served.WedeterminedthelevelsofheterogeneitybytheI2statis-
episodesorretching,andtheuseofpharmacological’rescue’anti-
tic(Higgins2011).Weusedarandom-effectsmodelwhentheI2
emetics.Alloutcomemeasuresthatwereevaluatedweredichoto-
wasmorethan50%.
mousand,assuch,weusedrelativerisk(RR)with95%confidence
interval(95%CI)tomeasuretreatmenteffect.
Subgroupanalysisandinvestigationofheterogeneity
Unitofanalysisissues Subgroupanalyseswereconductedwheredatawereavailable,as
Forcross-overtrials,apairedt-testwastobeusedtoanalysepar- describedbyDeeksetal(Deeks2001)and asrecommendedin
ticipantdatahadsufficientdatabeenavailable.Hadclusterran- Section 8.8 of the Cochrane Handbook for Systematic Reviews of
domizedtrialsbeenincluded,effectestimatesandstandarderrors Interventions(Higgins2011).Weplannedtocompare:
wouldhavebeenmeta-analysedusingthegenericinverse-variance • adultsandchildren;
methodinRevMan. • differenttypesofsurgery(e.g.orthopaedicand
gynaecologicsurgery);
• typesofaromatherapydeliverymethods(e.g.inhalation,
Dealingwithmissingdata
massage,ingestion);
Wherenecessary,wecontactedauthorsofincludedstudiesregard- • trialquality(e.g.RCT,CCT).
ingmissingstudyinformation.Wewereabletocontactsomeau-
thorstoretrievemissingdata,suchasdetailsaboutrandomization, Duetothelimiteddataavailable,wewereunabletoperformany
statisticaldetailandstandarddeviations,howeverothersdidnot subgroupanalyses.
replyorwerenotcontactable.Wheredatawerefoundtobemiss-
ingandtheauthorswerenotcontactable,wherepossiblewecal-
Sensitivityanalysis
culatedmissingstatistics(suchasstandarddeviations)fromother
quotedstatistics(suchasstandarderrorsorCIs).Ifmissingdata Because of considerable concern about the risk of bias due to
remainedthenweperformedanavailablecaseanalysis,excluding confoundinginMerritt2002weperformedasensitivityanalysis
datawhereoutcomeinformationwasunavailable. andhavereportedfindingsbothwithandwithouttheresultsof
thisstudy.
Assessmentofheterogeneity
WeassessedstatisticalheterogeneitythroughtheuseoftheChi2
test,aswellasbyreviewingtheI2statistic.IfeithertheChi2test
resultedinaPvaluelessthan0.10ortheI2 statisticwasgreater RESULTS
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 7
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Descriptionofstudies We conducted searches in a wide range of databases and
sources:MEDLINE;CAMonPubMed;CENTRAL;EMBASE;
See:Characteristicsofincludedstudies;Characteristicsofexcluded
CINAHL; Meditext; LILACS; Web of Science; Current Con-
studies.
trolledTrials;ClinicalStudyResults;SIGLE;NewYorkLibrary
The studies were randomized controlled trials (RCTs) or con-
ofMedicineGreyLiteratureReport;NationalInstituteofClinical
trolled clinical trials (CCTs) conducted on postoperative adult
Studies;GoogleScholar(English,German,Spanish);Science.gov
andpaediatricpatientsinpostanaesthesiacareunits(PACU)and
(greyliterature);ConferenceProceedingsoftheNationalAssoci-
same-day surgery units (SDSU). The intervention groups were
ationforHolisticAromatherapy;andreferencelists.
givenaromatherapytreatmentstotreatcomplaintsofpostopera-
Of the 1386 articles we identified, 44 were deemed relevant
tivenauseaandvomiting. Thecontrolgroupsweretreatedwith
enough tobe retrievedfor furtherevaluation. Afterappraisal of
eitherasalineplaceboorstandardanti-emeticdrugs.
thefullversionofeachstudy,ninestudieswerefoundtomeetthe
criteriaforinclusioninthereview.ForfurtherdetailsseeFigure1.
Resultsofthesearch
Aromatherapyfortreatmentofpostoperativenauseaandvomiting(Review) 8
Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.