Physician anaesthetists versus non-physician providers of anaesthesia for surgical patients

80 Pages·2014·0.7 MB·English

Physician anaesthetists versus non-physician providers of
anaesthesia for surgical patients (Review)
Lewis SR, NicholsonA, Smith AF, Alderson P
ThisisareprintofaCochranereview,preparedandmaintainedbyTheCochraneCollaborationandpublishedinTheCochraneLibrary
2014,Issue7
http://www.thecochranelibrary.com
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review)
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
ADDITIONALTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
DIFFERENCESBETWEENPROTOCOLANDREVIEW . . . . . . . . . . . . . . . . . . . . . 75
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) i
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
[InterventionReview]
Physician anaesthetists versus non-physician providers of
anaesthesia for surgical patients
SharonRLewis1,AmandaNicholson2,AndrewFSmith3,PhilAlderson4
1Patient SafetyResearch,Royal Lancaster Infirmary, Lancaster, UK.2Liverpool Reviews andImplementation Group, University of
Liverpool,Liverpool,UK.3DepartmentofAnaesthetics,RoyalLancasterInfirmary,Lancaster,UK.4NationalInstituteforHealthand
CareExcellence,Manchester,UK
Contactaddress:SharonRLewis,PatientSafetyResearch,RoyalLancasterInfirmary,PointerCourt1,AshtonRoad,Lancaster,LA1
1RP,[email protected]@googlemail.com.
Editorialgroup:CochraneAnaesthesiaGroup.
Publicationstatusanddate:New,publishedinIssue7,2014.
Reviewcontentassessedasup-to-date: 13February2014.
Citation:LewisSR,NicholsonA,SmithAF,AldersonP.Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgical
patients.CochraneDatabaseofSystematicReviews2014,Issue7.Art.No.:CD010357.DOI:10.1002/14651858.CD010357.pub2.
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
ABSTRACT
Background
With increasing demand for surgery, pressure on healthcare providers to reduce costs, and a predicted shortfall in the number of
medicallyqualifiedanaesthetistsitisimportanttoconsiderwhethernon-physiciananaesthetists(NPAs),whodonothaveamedical
qualification,areabletoprovideequivalentanaestheticservicestomedicallyqualifiedanaesthesiaproviders.
Objectives
To assess the safety and effectiveness of different anaesthetic providers for patients undergoing surgical procedures under general,
regional or epidural anaesthesia. Weplannedtoconsider resultsfromstudies acrosscountries worldwide (including developedand
developingcountries).
Searchmethods
WesearchedtheCochraneCentralRegisterofControlledTrials(CENTRAL),MEDLINE,EMBASEandCINAHLon13February
2014.Oursearchtermswererelevanttothereviewquestionandnotlimitedbystudydesignoroutcomes.Wealsocarriedoutsearches
ofclinicaltrialsregisters,forwardandbackwardcitationtrackingandgreyliteraturesearching.
Selectioncriteria
Weconsideredallrandomizedcontrolledtrials(RCTs),non-randomizedstudies(NRS),non-randomizedclustertrialsandobservational
studydesignswhichhadacomparisongroup.WeincludedstudieswhichcomparedananaestheticadministeredbyaNPAworking
independentlywithananaestheticadministeredbyeitheraphysiciananaesthetistworkingindependentlyorbyaNPAworkingina
teamsupervisedordirectedbyaphysiciananaesthetist.
Datacollectionandanalysis
Threereviewauthorsindependentlyassessedtrialqualityandextracteddata,contactingstudyauthorsforadditionalinformationwhere
required.Inadditiontothestandardmethodologicalprocedures,webasedourriskofbiasassessmentforNRSonthespecificNRS
riskofbiastoolpresentedattheUKCochraneContributors’MeetinginMarch2012.Weconsideredcase-mixandtypeofsurgical
procedure, patient co-morbidity, type of anaesthetic given, and hospital characteristics as possible confounders in the studies, and
judgedhowwelltheauthorshadadjustedfortheseconfounders.
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 1
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Mainresults
WeincludedsixNRSwith1,563,820 participants.Fivewerelargeretrospectivecohortstudiesusingroutinelycollectedhospitalor
administrativedatafromtheUnitedStates(US).ThesixthwasasmallercohortstudybasedonemergencymedicalcareinHaiti.Two
wererestrictedtoobstetricpatientswhilsttheothersincludedarangeofsurgicalprocedures.Itwasnotpossibletocombinedataas
therewasadegreeofheterogeneitybetweentheincludedstudies.
TwostudiesfailedtofindadifferenceintheriskofdeathinwomenundergoingcaesareansectionwhengivenanaesthesiabyNPAs
comparedwithphysiciananaesthetists,bothworkingindependently.Onestudyreportedtherewasnodifferenceinmortalitybetween
independentlyworkingprovidergroups.OnecomparedmortalityrisksbetweenUSstatesthathad,orhadnot,’opted-out’offederal
insurancerequirementsforphysiciananaesthetiststosuperviseordirectNPAs.ThisstudyreportedalowermortalityriskforNPAs
workingindependentlycomparedwithphysiciananaesthetistsworkingindependentlyinboth’opt-out’and’non-optout’states.
OnestudyreportedalowermortalityriskforNPAsworkingindependentlycomparedwithsupervisedordirectedNPAs.Onereported
ahighermortality riskfor NPAsworking independentlythanin asupervised or directedNPAgroupbut nostatistical testing was
presented.OnereportedalowermortalityriskintheNPAgroupworkingindependentlycomparedwiththesupervisedordirected
NPAgroupinboth’opt-out’and’non-optout’statesbeforethe’opt-out’rulewasintroduced,butahighermortalityriskin’opt-out’
statesafterthe’opt-out’rulewasintroduced.Onereportedonlyonedeathandwasunabletodetectariskinmortality.Onereported
thattheriskofmortalityandfailuretorescuewashigherforNPAswhowerecategorizedasundirectedthanfordirectedNPAs.
Threestudiesreportedtheriskofanaesthesia-relatedcomplicationsforNPAsworkingindependentlycomparedtophysiciananaesthetists
workingindependently.Twofailedtofindadifferenceintheriskofcomplicationsinwomenundergoingcaesareansection.Onefailed
tofindadifferenceinriskofcomplicationsbetweengroupsin’non-optout’states.Thisstudyreportedalowerriskofcomplications
forNPAsworkingindependentlythanforphysiciananaesthetistsworkingindependentlyin’opt-out’statesbeforethe’opt-out’rule
wasintroduced,butahigherriskafter,althoughthesedifferenceswerenottestedstatistically.
TwostudiesreportedthattheriskofcomplicationswasgenerallylowerforNPAsworkingindependentlythanintheNPAsupervised
orteamgroupbutnostatisticaltestingwasreported.Onereportednoevidenceofincreasedriskofpostoperativecomplicationsinan
undirectedNPAgroupversusadirectedNPAgroup.
Theriskofbiasandassessmentofconfounderswasparticularlyimportantforthisreview.Wewereconcernedabouttheuseofroutine
dataforresearchandthelikelyaccuracyofsuchdatabasestodeterminetheinterventionandcontrolgroups,thusjudgingfourstudies
atmediumriskofinaccuracy,oneatlowandone,forwhichtherewasinsufficientdetail,atanunclearrisk.Whilstweexpectedthat
mortalitywouldhavebeenaccuratelyreportedinrecordsystems,wethoughtreportingmaynotbeasaccurateforcomplications,which
reliedontheuseofcodes.Studieswerethereforejudgedasathighriskoranunclearriskofbiasforthereportingofcomplicationsdata.
Fourofthesixstudiesreceivedfunding,whichcouldhaveinfluencedthereportingandinterpretationofstudyresults.Studiesconsidered
confoundersofcase-mix,co-morbidityandhospitalcharacteristicswithvaryingdegreesofdetailandagainwewereconcernedabout
theaccuracy of thecoding of data in recordsand the variablesconsidered during assessment. Five of the studies usedmultivariate
logisticregressionmodelstoaccountfortheseconfounders.Wejudgedthreeasbeingatlowrisk,oneatmediumriskandoneathigh
riskofincompleteadjustmentinanalysis.
Authors’conclusions
Nodefinitivestatementcanbemadeaboutthepossiblesuperiorityofonetypeofanaesthesiacareoveranother.Thecomplexityof
perioperativecare,thelowintrinsicrateofcomplicationsrelatingdirectlytoanaesthesia,andthepotentialconfoundingeffectswithin
thestudiesreviewed,allofwhichwerenon-randomized,makeitimpossibletoprovideadefinitiveanswertothereviewquestion.
PLAIN LANGUAGE SUMMARY
Physiciananaesthetistsversusnurseanaesthetistsforsurgicalpatients
Background
Thereisanincreasingdemandforsurgery,pressureonhealthcareproviderstoreducecosts,andapredictedshortfallinthenumberof
medicallyqualifiedanaesthetists.Thisreviewaimedtoconsiderwhetheranaesthesiacanbeprovidedequallyeffectivelyandsafelyby
nurseanaesthetists(withoutmedicalqualifications)asbymedicallyqualifiedanaesthetistswithspecialisttraining.
Studycharacteristics
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 2
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Theevidencewascurrentupto13February2013.Wefoundsixrelevantstudies,fiveofwhichwerelargeobservationalstudiesfrom
theUSwithacomparisongroupandwithstudydurationsfromtwoto11years,andonewasamuchsmaller12weekstudyfromHaiti.
Therewereover1.5millionparticipantsinthestudies.InformationforthesestudieswastakenfromAmericaninsurancedatabases
(Medicare)andfromhospitalrecords.Thesmallstudywasbasedonemergencymedicalcareafterthe2008hurricanesinHaiti.
Keyresults
Moststudiesstatedthattherewasnodifferenceinthenumberofpeoplewhodiedwhengivenanaestheticbyeitheranurseanaesthetist
oramedicallyqualifiedanaesthetist.Onestudystatedthattherewasalowerrateofdeathfornurseanaesthetistscomparedtomedically
qualifiedanaesthetists.Onestudystatedthattheriskofdeathwaslowerfornurseanaesthetistscomparedtothosebeingsupervised
byananaesthetistorworkingwithinananaestheticteam,whilstanotherstatedtheriskofdeathwashighercomparedtoasupervised
orteamapproach.Otherstudiesgavevariedresults.Similarly,therewerevariationsbetweenstudiesfortheratesofcomplicationsfor
patientsdependingontheiranaestheticprovider.
Qualityoftheevidence
Much of the data came from large databases, which may have contained inaccuracies in reporting. There may also be important
differencesbetweenpatientsthatmightaccountforvariationinstudyresults,forexample,whetherpatientswhoweremoreillwere
treatedbyamedicallyqualifiedanaesthetist,orwhethernurseanaesthetistsworkedinhospitalsthathadfewerresources.Severalofthe
studieshadallowedforthesepotentialdifferencesintheiranalysis,howeveritwasuncleartouswhetherthishadbeendonesufficiently
welltoallowustobeconfidentabouttheresults.Therewasalsopotentialconfoundingfromthefundingsourcesforsomeofthese
studies.
Conclusion
Asnone of thedatawere ofsufficiently high quality and thestudiespresentedinconsistent findings, we concludedthatitwas not
possibletosaywhethertherewereanydifferencesincarebetweenmedicallyqualifiedanaesthetistsandnurseanaesthetistsfromthe
availableevidence.
Roleofnon-physiciananaesthetists
BACKGROUND
Internationally there are challenges for the provision of anaes-
theticservices.Currentandpredictedshortfallscanbeexplained
byanageingpopulation,increasingdemandforsurgery,changesto
Forthepurposeofthisreview,andtoavoidconfusion,theword
workinghours,migrationofanaesthetists,pressureonhealthcare
’physiciananaesthetist’isusedforallpersonnelwhoaremedically
costsandinsomecountriesareductioninthenumberofmedical
qualified,and’non-physiciananaesthetist’(NPA)forallthosewho
graduateschoosingtospecializeinanaesthesia(Egger2006;Egger
provideanaesthesiawithoutamedicalqualification.Thisincludes
2007;Jordan2011).
achangeoftermsfordiscussionregardingsomecountries,forex-
ample,intheUStheyarenormally referredtoas’anesthesiolo-
Similarpressuresareseeninotherfieldsofhealthcare,resulting
gists’and’certifiedregisterednurseanesthetists’(orCRNAs),re-
inatrendtowardstheuseofanurse-ledratherthanatraditional
spectively.
doctor-ledservice,suchasinprimarycareandmonitoringoflong
There are considerable differences in the organization of anaes-
termconditions. However,thedevelopmentofsimilar substitu-
thetic teams across Europe and internationally (Egger 2007;
tionswithinthefieldofanaesthesiahasbeenmetwithmoreresis-
Meeusen2010),whereanaestheticsmaybeadministeredbyphysi-
tance(Smith2005).
ciananaesthetistsworkingaloneoraspartofananaestheticteam,
Withregardtocostcontainment,thereisasubstantialdifference orbyNPAswhointurnmaybeworkingaloneoraspartofan
inthesalariesofthetwopersonnelwithincountries(intheUnited anaestheticteam(Bacon2002).Betweencountriestherearealso
States(US),forexample,thesalaryofananaesthetistisapproxi- significantdifferencesinthelengthoftrainingofpersonnel(Egger
matelydoublethatofnon-physicianpersonnel(Kalist2011)). 2007;Matsusaki2011;Meeusen2010).
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 3
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Non-physiciananaesthetists(NPAs)indevelopingcountries thesiacanonlybeachievedbyaphysician-onlyservice”(AAGBI
2010).
Lowandmiddleincomecountries,withlargepopulationslivingin
Despitedifferencesinopinionregardingthelengthoftrainingof
rurallocations,havefewphysiciananaesthetistswithratiosofless
NPAs in some countries, the potential benefits of independent
thanoneper100,000population.Forexample,Ugandahasap-
practiceareevident,particularlyinruralareaswhichattractfewer
proximatelyonephysiciananaesthetistpertwomillionpopulation
anaesthetists.
(Dubowitz2010)asopposedtotheUKwhichhas12,000per64
million,thatis1:5000(Walker2007).Thesecountrieshavebeen
using non-physician personnel to deliver many anaesthetic ser-
vices,forexample,Kenya’snurseanaesthesiatrainingprogramme
Impactofuseofnon-physiciananaesthetists(NPAs)on
(Newton2010).
patientcare
The debate over the use of NPAs has focused on patient safety
andthequestionofwhetherdifferentprovidersdeliverequivalent
Non-physiciananaesthetists(NPAs)intheUS qualityandsafetytopatients.
A systematic review has beencarried out by Smith etal (Smith
TheUShasalonghistoryofusingnursestoadministeranaesthet-
2004).Theyidentifiedfourarticlesrelevanttothereviewques-
ics.However,asanaesthesiahasdevelopedasaphysicianspecialty
tion, none of which were randomized controlled trials (RCTs).
there is now a majority of medically qualified anaesthetists and
Theauthorswereunabletoshowanysignificantdifferenceinthe
considerable debate exists between the two professional groups
safetyofusingdifferentanaestheticproviders,howevertheyalso
regardingrolesandresponsibilities(Bacon2002;Gardner2011;
concluded that, given the methodological flaws in the available
Matsusaki2011).Kalist2011says“thereissomuchoverlapbe-
studies,thiswasnotevidenceofabsenceofadifference.
tweentheworktheydothatitisnotclearwhetheranMDA(physi-
Apart from anxieties over patient safety, there are other factors
ciananaesthetist)actuallydoesanythingthataCRNA(NPA)does
involvedinhowfartheroleofanNPAshouldbedeveloped,suchas
notdo”.Inrecentyears,changestostatelawintheUSwithregard
threatstomedicallyqualifiedphysiciananaesthetists’professional
to Medicare and Medicaid reimbursement allow some NPAsto
status,accesstotrainingandworkingpractices,aswellasthewish
now practice without supervision fromaphysiciananaesthetist.
toavoidthecostlyandlengthyinterprofessionalconflictthatexists
Atpresentthereare17stateswhohave’optedout’andNPAscan
intheUS(Kane2004;Smith2005).
practiceassuch(AANAFactSheet).Millionsofdollarshavebeen
spentlobbyingfororagainstthisruling(Bacon2002).
Whyitisimportanttodothisreview
Increasing demands on healthcare systems together with a pre-
Non-physiciananaesthetists(NPAs)intheUKandother
dictedpersonnelshortfallandthecurrentemphasisoncostcon-
developedcountries
tainmentmakethisatimelyandimportantreview.
In other developed countries there is variation in the changing
This review updates Smith’s existing review (Smith 2004) and
rolesandresponsibilitiesofanaestheticproviders.Amoveinsome
aimedtoestablishwhatisknownaboutpatientsafetywhenanaes-
EuropeancountriesnowseesNPAsabletoinducegeneralanaes-
theticsareadministeredbydifferentpersonnel.Wehopedthatthis
thesia for American Society of Anesthesiologists (ASA)I and II
mayleadtoanincreaseinconfidenceintheskillsofNPAswithin
patientsundertheindirectsupervisionofaphysiciananaesthetist
the anaesthetic community and may potentially lead to greater
(forexample,inDenmark,France,NorwayandSweden),whilst
flexibilityinteamroles,bothwithinandbetweencountries,de-
insomecountries(forexample,NetherlandsandNorway)nurse
pendingonpatientneed.
anaesthetistswithadditionaltrainingarealsoabletogivesedation
undermonitoredanaesthesiacare(MAC),againunderindirectsu-
pervision(Meeusen2010).Thesecountrieshowevercontinueto
resistamovetowardsunsupervisedNPAs.IntheUK,theintroduc-
tionofananaesthesiaphysicianassistant,nowcalledphysicianas- OBJECTIVES
sistant(anaesthesia)(PA(A)),pilottrainingprogrammefromOc-
To assess the safety and effectiveness of different anaesthetic
tober2003attemptedtoaddressthepredictedshortfallofphysi-
providersforpatientsundergoingsurgicalproceduresundergen-
ciananaesthetists(Wilkinson2007).However,therearelimitsto
eral,regionalorepiduralanaesthetic.
theresponsibilitiesgiventoaPA(A)andtheyareprovidedwith
supervisionfromaphysiciananaesthetist.Aftertheintroduction Asubsidiary question was todetermine whetherthereare types
ofPA(A)s,theAssociation ofAnaesthetistsofGreatBritainand ofproceduresorpatientgroupsforwhichanon-physiciananaes-
Irelandmaintainsanopinionthat“thehigheststandardsofanaes- thetist is not appropriate. We planned to consider results from
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 4
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
studieswithindifferentregions(US,UK,otherdevelopedcoun- withinateam.SomeNPAsmaybedescribedasbeing’medically
triesanddevelopingcountries)initiallyandthenassesswhether directed’(anaestheticisperformedbyanNPAwhilstthephysician
theresultswereconsistentacrossregionsbeforecombiningresults. anaesthetistoverseesnomorethanfourconcurrentprocedures)or
working’undersupervision’(anaestheticisperformedbyanNPA
who is directed by a physician other than the physician anaes-
METHODS thetist).Weensuredthatwefollowedtheabovedefinitionsasfar
aspossible,aimingtocontactauthorsforclarificationifnecessary
toavoidmisclassificationoftheinterventionandcomparisonin
thestudies.
Criteriaforconsideringstudiesforthisreview
Typesofoutcomemeasures
Typesofstudies
WeaimedtoincludeRCTs,quasi-randomizedtrialsinwhichthe
allocationtotheinterventionwasdecidedbynon-randommeans
Primaryoutcomes
(suchasalternation,digitsindateofbirthorotheridentification
1. Mortalitywithin30daysofanaesthetic
(ID)number)andclusterrandomizedtrials.
2. Failuretorescuebetweeninductionandfullrecovery
IntheabsenceofRCTs,weincludednon-randomizedcontrolled
(“definedastherateofdeathaftercomplications”(Silber2000a))
trials(NRCTs)andnon-randomizedclustertrials.Weconsidered
3. Anaesthesia-relatedcomplications(includingcardiac,
alldesignsofobservationalstudieswhichincludedacomparison
pulmonaryandcentralnervoussystemcomplicationsdueto
group, including prospective and retrospective cohortstudy de-
anaesthesiaallwithin30daysofanaesthetic)
signs, controlledbefore-afterstudy designs, prospectiveandret-
rospectivecase-controlstudydesignsandinterruptedtime-series.
Wedidnotincludedescriptivestudieswithoutadirectcompari-
Secondaryoutcomes
songroup.
IfwehadidentifiedanyRCTsweplannedtoconsidernon-ran- 1. Otherminoranaestheticcomplications(suchasnauseaand
domizedstudies(NRS)separatelyandnotincludetheminameta- vomiting,pain,sorethroat,dentaldamage)within48hours
analysis. 2. Lengthofhospitalstay
3. Cost
4. Patientreportedsatisfaction
Typesofparticipants
Weincludedstudiesofpatientsofallagesundergoingemergency
orelectivesurgeryundergeneralorregionalanaestheticinahospi- Searchmethodsforidentificationofstudies
talsetting.Wealsoincludedpatientsundergoingobstetricsurgery.
Typesofinterventions Electronicsearches
Weincludedstudieswhichcomparedananaestheticadministered We searched for eligible trials in the following databases: the
byanNPAworkingindependentlywitheither: CochraneCentralRegisterofControlledTrials(CENTRAL)(The
1. ananaestheticadministeredbyaphysiciananaesthetist Cochrane Library 2014, Issue 2), MEDLINE (via Ovid) (from
workingindependently; 1985 to February 2014), EMBASE (via Ovid) (from 1985 to
2. ananaestheticadministeredbyaNPAworkinginateam February2014)andCINAHL(viaEBSCO)(from1985toFebru-
whichwassupervisedordirectedbyaphysiciananaesthetist. ary2014).Wealsosearchedtrialregisters,www.clinicaltrials.gov
Wehavetakenintoconsideration thedifferenceinterminology andtheWorldHealthOrganization(WHO)InternationalClin-
of anaesthetic personnel between countries, which can poten- icalTrialsRegistryPlatform(http://www.who.int/ictrp/network/
tiallyleadtoconfusion(Vickers2002).Throughoutwehaveused en/), for ongoing trials. We also searched Health Management
theterms’physiciananaesthetist’and’non-physiciananaesthetist’ InformationConsortium(HMIC)viaOvid,whichincludesgrey
(NPA),asdefinedabove.Examplesofdifferentnamesforanaes- literature.
theticpersonnelaregiveninAppendix1.Whereastudyauthor The search strategies for MEDLINE, EMBASE, CINAHL and
usedanuncleartermtodescribeananaestheticproviderthatwe CENTRALarepresentedinAppendix2.Thesearchstrategydid
wereunabletodesignatetooneoftheabovecategories,weaimed not include any outcomes and was not limitedby study design
tocontacttheauthorstoseekclarification.Therearealsovarious orpublicationtype.Nolanguagerestrictionswereimposed.On
termsusedtodescribetheroleofthemainanaestheticpractitioner retrievalofstudiesweassessedanyfreetexttermsorMeSHterms
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 5
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
forNPAs,andifwehadnotusedthemwewouldhaveincluded Appendix3).Thisformwasreviewedafterdatafromthefirstthree
theseinamodifiedsearchstrategy. papershadbeenentered,andmodifiedasrequired. If duplicate
publications from the same study were identified, we created a
compositedatasetfromalltheeligiblepublications.
Searchingotherresources
The following items were included in the NRS data extraction
Weidentifiedotherrelevantsystematicreviewsinthesearchand form:
undertook forward and backward citation tracking for key arti- • methods,toincluderiskofbiasassessments(seebelow);
cles. We contacted study authors to ask if they knew of other • patientgroup,toincludeage,sex,relevant
relevantongoingorunpublishedstudies.InSeptember2013we sociodemographics,case-mix;
searchedthefollowingclinicaltrialsdatabases:ClinicalTrials.gov, • setting,e.g.ruralorurban,country;
the metaRegister for Controlled Trials, and the WHO Interna- • intervention,toincludetraining,experienceandthelevelof
tionalClinicalTrialsRegistryPlatform. supervision,roleandresponsibilitiesofNPA;
• comparison,toincludetrainingandexperienceof
anaesthetist;
Datacollectionandanalysis • outcome,toincludetimepointsi.measuredandii.
reported,unitofmeasurement;
• analyticmethodsincludingUnitofanalysisissues;
• results,toincludemissingparticipants,subgroupanalyses,
Selectionofstudies
bothunadjustedandadjustedresults.
Resultsofthesearcheswerecollatedandduplicatesremoved.All
titlesandabstractswerescreenedbytwoauthors(SharonRLewis Ifrelevantinformationordatawerenotavailableinthepaper,we
(SRL)andAmandaNicholson(AN))toremovestudiesthatwere attemptedtocontacttheleadauthortorequesttheadditionalde-
very unlikelytobe eligible. Apilotof 100 titleswas performed tails.Disagreementswereresolvedbydiscussionand,ifnecessary,
beforealltitleswerereviewedinordertoclarifycriteriafordis- consultationwithAFS.
carding articlesatthisstage. Weplannedtoidentify potentially
eligibleRCTsandNRSseparately.Ifnoabstractwasavailablebut
Assessmentofriskofbiasinincludedstudies
thetitlewaspossiblyrelevant,thefulltextofthearticlewasob-
WeanticipatedthatwewouldencounterarangeofNRSdesigns.
tained.Weanticipatedthatwewouldneedtogetmorefulltexts
WebasedourriskofbiasassessmentforNRSonthespecificNRS
for observational studies as abstracts may not contain sufficient
riskofbiastoolpresentedattheUKContributors’Meeting2012
detailtoallowclassification(Section13.3.1.3)(Higgins2011).
(incorporatedintothedataextractionformforNRS(Appendix
Whenalltitlesandabstractswerescreened,thefulltextsofpoten-
3)).
tiallyrelevanttitleswerereviewedbySRLandANandthedata
ThedirectionandimpactofbiasacrossdifferentNRSisdepen-
wererecordedonthestudyeligibilitysectionofthedataextraction
dentonindividualstudyfeaturesandhencehugelyvariableand
form.WeplannedtohaveseparateeligibilityformsforRCTsand
difficulttopredict(Deeks2003).Inthisreview,selectionbiasand
NRS (copies are included in Appendix 3). The NRS eligibility
confoundingbyindicationwereofparticularconcern.
formusedstudy design featuresratherthanstudy designlabels,
Riskofbiasforeachdomainwasjudgedashigh,loworunclear,
based on the tools presented at the UK Contributors’ Meeting
unlessspecifiedotherwise.
2012,whichwerethenmodifiedtosuitourreviewneeds.These
featuresfall into four groups: Was therea relevantcomparison?
Howwerethegroupsformed?Werethefeaturesofthestudyde-
Allocation(selectionbias).
scribedbelowcarriedoutafterthestudywasdesigned?Onwhat
Aspartofourassessmentofstudydesignwerecordedthefactors
variableswascomparabilityofgroupsassessed?Thesewereincor-
which determined participant allocation to the intervention or
poratedintothedataextractionform(Appendix3).
controlgroup.
Apilotselectionof10paperswerereadbySRLandANandthen
theinvestigatorsmettocompareresultsandmodifytheformsas
required. SRL and AN then read all potentially relevant papers Blinding(performanceanddetectionbias)
andmettocompareresults.Wereferredanydifferencesthatcould
notberesolvedbydiscussionontoAndrewFSmith(AFS).
Accuracywithwhichtheinterventionorcontrolgroup
Dataextractionandmanagement determined
Data wereextractedfromeligible studies bySRL, ANand Phil We recorded whether the study personnel or participants were
Alderson (PA) using a paper-based data extraction form (see blindedtotheallocationofparticipantsandanyothermeasures
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 6
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
takentoensurethatthetreatmentofintervention andcompar- Allthesevariablesareplausiblyassociatedboth withparticipant
isongroupswereequivalentinallaspectsotherthananaesthetic outcomeandwiththetypeofanaestheticproviderandsocould
provider.Inadditionwerecordedthemethodsanddatausedto accountforanyobservedassociationbetweenanaestheticprovider
decidewhichpatientsbelongedtotheinterventionorcomparison andparticipantoutcome.
group,withanestimateoftheriskofinaccuracyscoredashigh, Usingthedataextractionform(Appendix3)foreachNRSwe:
medium,loworunclear. • identifiedtherelevantconfoundersdescribedbythe
researcher;
• identifiedthemethodforidentifyingrelevantconfounders
asdescribedbytheresearchers;
Accuracywithwhichoutcomesassessed
• scoredallconfounders,includingthosenotspecifiedbythe
Forstudiesusingroutinehospitaldatatheremaybeerrorsoromis- researchersfor
sionsinrecordingoutcomes,dependingoncodingpracticewithin
the hospital. Failure to rescue rates, which rely on the record- 1. theriskofimprecisioninmeasurementofconfounder,
ingofacomplicationbeforedeath,havebeenshowntobevery scoredashigh,medium,loworunclear,
sensitivetothecompletenessofcodingofthesesecondary diag- 2. theriskofimbalanceinconfounderbetweenprovider
noses(McKee1999).Iftheinterventionandcomparisongroups groups,scoredashigh,medium,loworunclear;
wereindifferenthospitalswithdifferentcodingpracticesthismay • identifiedthemethodusedforcontrollingforconfounding
atboththedesignandanalysisstage;
haveaconsiderableinfluenceonresults.Weassessedwhetherthe
• judgedtheriskofincompleteadjustmentduringanalysisas
outcome data were recorded with knowledge of the anaesthetic
high,medium,loworunclear.
providergroup(blinding)andalsoassessedtheriskofinaccuracy
ofoutcomedata,scoredashigh,medium,loworunclear.
Measuresoftreatmenteffect
Incompleteoutcomedata(attritionbias) Onthedataextractionformwerecordedallunadjustedandad-
Thislargelydependsontheaccuracyandcompletenessofoutcome justed effect estimates for all eligible outcomes, with details of
data. This relies in part on the accuracy with which outcomes confoundersincludedforeachestimate.Regressioncoefficientsor
areidentifiedwithinthedataset,asdiscussedabove,butalsoon analysisofcovariance wouldhavebeenrecordedforcontinuous
thecoverageoftheoutcomedataset.Importantquestionsinclude variables.
whetherallparticipantswerecorrectlyidentifiedandlinkedtothe Inanattempttocontrolforconfounding,weusedadjustedrather
outcomedataset. than unadjusted effect estimates from NRS in the analysis and
discussion ofstudyfindings. Ifmultipleadjustedestimateswere
given we used the estimate thatincluded the largest number of
Selectivereporting ourpre-determinedkeyconfounders.
Registration of protocols and analysis plans is not as common
for observational studies as for RCTs and there is scope for the
Unitofanalysisissues
study authors to present results only on outcomes found to be
significantlyassociatedwiththeinterventionofinterest.Thisisa Theinterventionorcomparisongroupmaybedecidedorassigned
particularriskwhenroutinedataareusedwhichhaveconsiderable atahospitallevelandthisneededtobeaccountedforinanyanal-
scopetostudyarangeofdifferentoutcomes.Werecordedwhether ysis,sincethesehospitalsmaydifferinmanyrespectsotherthan
thestudyauthorshadpublishedanalysisplansorprotocols. anaesthetic provider. Incorrect analysis would result in residual
confoundinginthemodelorinaccurateconfidenceintervals.The
useofmulti-levelorhierarchicalmodelsorrobuststandarderrors
Otherpotentialsourcesofbias wasrecordedandiftheappropriateanalysiswasnotreportedwe
Weconsideredthefundingsourcesforeachstudyandanyresulting plannedtocontacttheauthors.
potentialconflictsofinterest.
Dealingwithmissingdata
Assessmentofcontrolforconfoundingfactors We contacted study authors to request missing outcome data
Importantconfoundingfactorsforthisresearchquestionare: oranyothermethodologicaldetails.Missingoutcomedatawere
• case-mixandtypeofsurgicalprocedure; likelytobemoreofanissueinRCTsorprospectivecohortstud-
• patientco-morbidity; ies,wheredataarecollectedspecificallyforthestudy.Ifwehad
• typeofanaestheticgiven; suitabledata,weplannedtoundertakesensitivityanalysestoas-
• hospitalcharacteristics. sesstheimpactofthemissingoutcomesusing,forexample,worst
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 7
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
casescenario, lastobservationcarriedforwardandavailablecase Weaimedtoincludeawiderangeofstudiesusingawidesearchand
analysis. didnotexcludeanypotentiallyeligiblearticleswithoutreference
tothefulltext.
Assessmentofheterogeneity
Datasynthesis
WeexpectedtofindmoreheterogeneitybetweenNRSthanbe-
WedidnotpoolestimatesofeffectsfromNRSstudies(Sections
tweenRCTs,reflectingdifferencesinstudydesignandscopefor
13.6.2.3and13.6.2.4)(Higgins2011).
bias,aswellasintrinsicdifferencesintheintervention(Sections
Ifwehadcomparableeffectestimateswewouldhavedisplayedthe
13.6.2.3and13.6.2.4)(Higgins2011).Ithasbeenestimatedthat
mostadjustedresultsfromeachstudyinaforestplotbutwithout
heterogeneity leads to uncertainty 5 to 10 times that of a 95%
apooledestimate.Astheresultsfromstudiesweretoodisparateto
confidence interval (Deeks2003). If we hadcomparable results
displaytogetherinaforestplotwehaveusednarrativesynthesis
foroutcomesindifferentstudiesweplannedtouseaforestplot
tosummarizethedirection,sizeandconsistencyofeffectsacross
todisplaythemostadjustedestimatesfromeachstudyandtouse
studies.
Chi2andI2statisticstodescribeheterogeneity.Studycharacteris-
ticsthatmaybeimportantinclude:
• numberofconfoundersincludedinmodels;
• analysistechniqueused;
• typeofdatacollection. RESULTS
Assessmentofreportingbiases Descriptionofstudies
Reportingbiasandmissingstudiesareamorecomplexissuefor SummarydetailsofeachstudyareinCharacteristicsofincluded
NRSthanforRCTs.Registrationandpublicationofprotocolsfor studies.
observationalstudiesisnotaswidespreadasforRCTssoitisnot
easytoidentifythefinitepopulationofstudiestobeincluded.For
Resultsofthesearch
thisresearchquestionthereisinfactanexistentialquestioncon-
cerningthedefinitionofaneligiblestudy.Sinceroutinehospital Therewere11,985studiesidentifiedfromelectronicsearches,161
databases are used in many studies, it could be argued that the studiesfromforwardcitationsearchingandafurther33fromback-
pool ofeligiblestudieswould includeallhospitalswhichutilize wardcitationsearching.Nostudieswereidentifiedfromclinical
arangeofanaestheticprovidersandhaveelectroniclongitudinal trialdatabases.Havingremovedduplicates,atotalof8102unique
healthdatabases.Itclearlywouldnotbepossibletoaccessallthese titles and abstracts were considered and thena further 169 full
databases.Itisnotclearwhetherthesizeofastudyordirection textsassessedforeligibility.Wewereunabletoobtainfulltextsfor
ofeffectarelikelytobeassociatedwithlikelihoodofpublication, fivestudiesandthesearelistedinStudiesawaitingclassification.
giventhatmany hospital studiesare verylarge butof uncertain Weperformeddataextractionandriskofbiasassessmentonsix
quality.Theseuncertaintiesunderminetheuseofafunnelplot. studies.Forthesearchflowdiagram,seeFigure1.
Physiciananaesthetistsversusnon-physicianprovidersofanaesthesiaforsurgicalpatients(Review) 8
Copyright©2014TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.