REVISTA
BRASILEIRA
DE
ANESTESIOLOGIA
PublicaçãoOficialdaSociedadeBrasileiradeAnestesiologia www.sba.com.brREVIEW
ARTICLE
Pain
after
sternotomy
---
review
Ana
Paula
Santana
Huang
a,
Rioko
Kimiko
Sakata
b,∗aEscolaPaulistadeMedicina,UniversidadeFederaldeSãoPaulo(Unifesp),SãoPaulo,SP,Brazil
bDepartmentofPain,UniversidadeFederaldeSãoPaulo(Unifesp),SãoPaulo,SP,Brazil
Received21February2014;accepted10September2014 Availableonline23April2016
KEYWORDS
Pain; Sternotomy; Postoperative analgesia
Abstract
Backgroundandobjective: Adequate analgesia after sternotomy reduces postoperative adverseevents.Therearevariousmethodsoftreatingpainafterheartsurgery,suchas infil-tration withalocal anesthetic,nerveblock,opioids,non-steroidal anti-inflammatorydrugs, alpha-adrenergicagents,intrathecalandepiduraltechniques,andmultimodalanalgesia.
Content: A review ofthe epidemiology,pathophysiology, prevention andtreatment ofpain after sternotomy.We alsodiscuss thevariousanalgesic therapeuticmodalities,emphasizing advantagesanddisadvantagesofeachtechnique.
Conclusions: Heartsurgeryisperformedmainlyviamediumsternotomy,whichresultsin signif-icantpostoperativepainandanon-negligibleincidenceofchronicpain.Effectivepaincontrol improvespatientsatisfactionandclinicaloutcomes.Thereisnoclearlysuperiortechnique.It isbelievedthatacombinedmultimodalanalgesicregimen(usingdifferenttechniques)isthe bestapproachfortreatingpostoperativepain,maximizinganalgesiaandreducingsideeffects. © 2015 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
PALAVRAS-CHAVE
Dor;
Esternotomia; Analgesia pós-operatória
Dorapósesternotomia---revisão
Resumo
Justificativaeobjetivo: Analgesia adequada após esternotomia reduz eventos adversos no pós-operatório. Várias modalidades estão disponíveis para tratamento dador após cirurgia cardíaca:infiltrac¸ãocomanestésicolocal,bloqueiodenervos,opioides,anti-inflamatóriosnão esteroidais,agentesalfa-adrenérgicos,técnicasintratecaiseepiduraiseanalgesiamultimodal.
∗Correspondingauthor.
E-mail:riokoks.dcir@epm.br(R.K.Sakata).
http://dx.doi.org/10.1016/j.bjane.2014.09.013
Conteúdo: Foifeitaumarevisãosobreepidemiologia,fisiopatologia,prevenc¸ãoetratamento dadorapósesternotomia.Tambémforadiscutidasasdiversasmodalidadesterapêuticas anal-gésicas,comênfaseemvantagensedesvantagensdecadatécnica.
Conclusões:A cirurgia cardíacaéfeitaprincipalmente poresternotomia média,que resulta emdorsignificativanopós-operatório eumaincidêncianãoinsignificante dedorcrônica.O controleefetivodadormelhoraasatisfac¸ãodospacienteseosdesfechosclínicos.Nenhuma técnicaéclaramentesuperior. Acredita-sequeumregimeanalgésicocombinadomultimodal (comváriastécnicas)sejaamelhorabordagemparatrataradorpós-operatória,oquemaximiza aanalgesiaereduzosefeitoscolaterais.
© 2015 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. Este é um artigo Open Access sob a licença de CC BY-NC-ND (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
Introduction
Due to the large number of cardiac surgeries annually performed and correlation between adequate control of postoperativepainand improved clinical outcomes, anes-thesiologistsmustdefendandimprovethevariouscurrent analgesictechniques.1
Poststernotomypainisacomplicationofcardiacsurgery. Theincidence, characteristics,and clinicalcourse of pain arenotwellunderstood. It isimportant todeterminethe incidenceandnatureofpoststernotomypainforprevention andtreatmentofpainsyndrome.2
Poorlycontrolledpainisassociatedwithsympathetic ner-vous system activation and increased hormonal response to stress. This response may contribute to the multi-ple postoperative adverse events, including myocardial ischemia, cardiac arrhythmias, hypercoagulability, pul-monary complications, and increased rates of delirium andwoundinfection.3---6Furthermore,severe painreduces
patientsatisfaction,delaystheonsetofwalking,andis asso-ciatedwiththedevelopmentofpostoperativechronicpain.7
Inadequate sputum, atelectasis, and pneumonia also occur due to pain. Immobilization by pain causes deep venousthrombosis,whichinturn mayresultinpulmonary thromboembolism.Pain is alsoa stress factor and causes myocardialinfarction,insomnia,anddemoralization.8
Pain can be classified as acute or chronic, somatic or visceral,andnociceptiveorneuropathic.Itoccurswhen tis-sueinjuryactivatesthepainreceptors(nociceptors)located in peripheral nerves. During surgery, several procedures can cause tissue trauma, such as incision, coagulation, stretchingorshrinkage.Thereisproductionandreleaseof substancesincludingprostaglandinsand bradykinin,which arepainmediators.9
Painmaybeassociatedwithmanysurgicalinterventions, includingincision,saphenousveinremoval,pericardiotomy orchesttubeinsertion,intraoperativedissectionand retrac-tionoftissue,amongothers.10
Theevaluationandqualificationofacutepaincanbevery variableanddependontheintervalbetweenassessments, aswellastheinstrumentusedtoquantify.Severalscalesare
usedinclinicalpracticetomeasurepain,includingnumeric scale, visual analog, verbal,andfacialexpression, among others.Somescalesaremoresuitablethanothersfor par-ticularpatientpopulations.Thefacialexpressionscalecan beusedbothforpatientsunabletocommunicate verbally andpatientswithtracheostomy.1
Epidemiology
Postoperative pain treatment is important because it is an unavoidable problem involving about 80% of patients undergoinganysurgery.Painissubjectiveandperceived dif-ferentlybyeachpatient.However,aninadequatecontrolof pain is commondue tofear ofside effects of analgesics, bothamongsurgeonsandpatients.10
Despite widely publicized, postoperative pain remains underestimated. Several studies have shown that despite thebesttreatment results,manypatientsstillsufferfrom moderatetoseverepostoperativepain.11,12
Inastudyassessingtheintensityofexpectedpainafter most surgical procedures and identifying the procedures in which the current pain therapy is insufficient, 115,775 patients were evaluated in 578 surgical centers. On the firstpostoperativeday,thepatientswereaskedabout the most severe pain sincesurgery, through averbal numeric scale(0---10).Theauthorsconcludedthatthe40procedures with the highest pain scores (mean of 6---7) included 22 orthopedicsurgeriesorlimbtrauma.Patientsreportedhigh painscoresafterminorsurgeries,includingappendectomy, cholecystectomy, hemorrhoidectomy, and tonsillectomy, while other major surgeries, such as abdominal,resulted in lower pain scores, often due to adequate epidural analgesia.13
Youngerpatientsseemtobemoreatriskofdeveloping chronic pain.15 Patients younger than 60 years had more
severepainthan olderpatients intheearly postoperative periodaftercardiacsurgery.16
The siteofinternalmammaryarterydissectionappears toincrease theincidenceof postoperativechronic pain.17
Myofascialsyndromeisalsocommonaftersternotomyand maycontributetochronicpain.Inareviewof1226patients undergoing sternotomy, the incidence of myofascial syn-drome was 15.8%, but in patients with dissected internal mammaryartery,theratewas75.5%.18
Inanotherprospectivestudyof705patientsundergoing cardiacsurgery,painrelatedtotheactivitieswasassessed dailyuntilthesixthpostoperativeday.Thepatientsreported the most severe pain when coughing, after movements, turning around or getting up from bed, and during deep breathing.Althoughpainscoreswerehighintheimmediate postoperativeperiod,patientsreportedameanpainscore of4.33whencoughingandof3.09duringdeepbreathingon thesixthdayaftersurgery.19
Inonestudy,theearlyremovalofchestdrainsinthefirst postoperativeday,comparedtothethirdday,alsoreduced painseverity.Withtheearlyremoval,patientshadlesspain intheepigastrium,chest,andshoulderonthethird postop-erativeday,withoutadverseevent.20
Anotherfactorthatreducedsurgicalpainseverityafter sternotomyisthepleurapreservation,whichalsoimproved pulmonaryfunctionaftersurgery.21
Chronic
pain
Theimportanceofpainintheearlypostoperativeperiodas achronicpainpredictoraftersternotomyisstilluncertain. It wassuggested that the severityof postoperative acute painand the need for large amounts of analgesics during the first postoperative daysmay be predictive of chronic pain.Thus,itisimportanttotreatthepostoperativeacute pain in order to stop the possible central and peripheral neuralmechanismsresponsibleforthetransitionfromacute tochronicpain.2
The authors of a study evaluated chronic pain in two groupsofpatientsaftersternotomy.Patientswith myasthe-niagravisundergoingthymectomyandthosewithmammary graft answered questionnaires. There was no difference in postoperative pain duration. Chronic pain was local-ized,mainly at thesite of sternotomyafter thymectomy; while after coronary artery bypass graft, it was also located in the upper and lower limbs.15 Brachial plexus
neuropathy wasattributed to the fracturedfragments of ribs,internalmammaryarterydissection,patient position-ing during surgery, and central venous catheter place of insertion.22Neuralgiaofthesaphenousnervewasreported
afterresectionofsaphenousveinforcoronaryarterybypass grafting.23
Inaprospectivestudy,theincidenceofchronicpainwas evaluated in patients undergoing sternotomy for cardiac surgery.Agroupof349patientswasassessedoneyearafter surgery. Of the 318 patients who answered the question-naire,28%reporteda chestdiscomfortdifferentfromthe oneprior tosurgery. In 13%,the visual analog scale max-imumscorewas30mm (moderatepain)and in4%, itwas
54mm(severepain).Themostcommondescriptionsofthe groupforpainwere:painfulprick,penetrating,and burn-ing.The authors concluded that,although the number of patientswithpoststernotomypainishigh(28%),onlyasmall portionreferredseverepainaftersternotomy.2
Chronic pain after heart surgery may become problematic.15,24 The cause of persistent pain after
ster-notomy is multifactorial and includes tissue destruction, intercostal nerve trauma, scar formation, rib fractures, sternal infection, stainless steel sutures and/or costo-chondralavulsion.Suchpainis oftenlocated inthearms, shouldersorlegs.25
In a study of 244 patients after cardiac surgery by sternotomy,persistent pain(definedaspainpersisting for morethan twomonths after surgery) wasseen in almost 30% of patients.24 The incidence of persistent pain
any-where was 29% and for sternotomy it was 25%. Other common sites were shoulders (17.4%), back (15.9%), and neck (5.8%). However, this pain wascommonly described as average pain, only 7% of patients reported inter-ference with daily activities. The most common words used to describe the pain were annoying (57%), uncom-fortable (33%), boring (30%), penetrating (25%), stressful (22%), sensitive (22%), and gripping (22%). The tempo-ral nature was mostly reported as brief/transient and periodic/intermittent.Twenty patients (8%) also reported symptomsof numbness,burning pain,tendernessoverthe saphenous harvesting site, and symptoms suggestive of acutecoronarysyndrome.Thus,theyconcludedthat mod-eratepainaftercardiacsurgeryandsternotomyiscommon, although it only rarely substantially interfere with daily activities.24
Pathophysiologyofacutepain
Postoperative pain mechanisms are complex, but gener-allyspeaking,inadditiontothenociceptivestimulusfrom direct tissue trauma, an inflammatory response leads to peripheral and central sensitization in pain experience. Mostof the pain after sternotomy occursbecause of tis-sulardamage in the skin, subcutaneous tissue,bone, and cartilage.1
Theintercostalnervesthatarisefromthethoracicnerve rootsinnervatethesternum,ribs,andtheadjacent subcu-taneous tissue.The main thoracic nerves that supply the sternum rangefrom T2to T6.The parietal pleura is also densely innervated by pain fibers that can be activated bybothmechanicalandchemicalstimulation.Incontrast, visceralpleurahasnosignificantsensoryinnervation. Peri-cardiumisinnervatedbysensoryfibersfromthevagusand phrenicnervesandsympathetictrunk.1
Paintreatment
Itisusuallydifficulttoachievesatisfactorypainreliefafter cardiac surgery. Inadequate analgesia or stress response notinhibitedduringthepostoperativeperiodmayincrease morbiditybyhemodynamic,metabolic,immunological,and hemostaticchanges.1
Pain is subjective and perceived differently by each patient. Inadequate pain control is common due to fear of side effects of analgesics, both among surgeons and patients.10
Traditionally, analgesia after heart surgery can be obtained with the use of intravenous opioids (particu-larlymorphine).However,theyareassociatedwithharmful adverseevents (nausea, vomiting,pruritus, urinary reten-tion,andrespiratorydepression).Furthermore,long-acting opioidssuchasmorphinemaydelaypostoperativetracheal extubation due to excessive sedation and/or respiratory depression.25
For early extubation, anesthesiologists are exploring otheroptionsbesidesthetraditionalintravenousopioidsto control postoperative pain. No technique is clearly supe-rior;probably,amultimodalapproachwithacombinationof analgesicsandtechniquesisthebestmethodtocontrol post-operativepain,maximizeanalgesia,andminimizeadverse events.25
Opioids
Intravenous opioids have been administered to patients undergoing cardiac surgery. Analgesia is reliable and can be used for long period. Disadvantages include pruritus, nausea and vomiting, urinary retention, and respiratory depression.26
Intravenouspatient-controlledanalgesia(PCA)hasbeen used extensively and is a safe and effective method for postoperative pain management.27,28 PCA was
supe-rior to nurse-controlled analgesia in poststernotomy patients.29
Inasmallrandomizedstudy,50 patientsreceived mor-phine,fentanyl,meperidine,remifentanilortramadolwith nodifferencesinpainscores,exceptforpatientsreceiving tramadolwhohadhigherpainscores.30
The authors of another study of intravenous PCA with remifentanil,morphineorfentanylreportednodifferences in painscores. However,patients who receivedmorphine hadahigher incidenceof nauseaandvomiting,while the fentanylgrouphadmorepruritus.31
Inastudyof60patientsreceivingintravenousmorphine for paincontrolafter sternotomy,painscores werelower inpatientswhoreceivedthecombination withbolus infu-sion than those treated with bolus alone; there was no differencein sedation scores andthere wereno episodes ofhypoxia.32 Also,therewasnodifferencein painscores
oradverseeventsinanothersimilarstudyof100patients, withintravenousmorphineinfusionassociatedwithbolusor bolusalone.33
Opioids are also involved in a variety of physiological functions, including pituitary management and activity and release of adrenal medulla hormone; cardiovascular and gastrointestinal function management; and breath, mood,appetite,thirst,cellgrowth,andtheimmunesystem
regulation.34 Opioids may cause various adverse events
including respiratory depression, pruritus, nausea and vomiting, urinary retention, constipation, bronchospasm, and hypotension, among others. The potential and well known adverse effects of opioids can limit postoperative recovery.1
Insummary,opioidsaremoreeffectivefortreatingpain after cardiac surgery, particularly when administered by PCA. It seems that there are no clinically significant dif-ferencesbetween opioids, and current evidence does not supporttheuseofbaselineinfusion associatedwithbolus. Adverseeventsshouldbeconsideredwhenchoosingadrug, but if several drugs are appropriate, the cost should be considered.1Patients’clinicalchangesshouldbeconsidered
whenselectingadrug.
Anti-inflammatorydrugs
Anti-inflammatorydrugsarethemostcommonlyuseddrugs for postoperativepaintreatment. In cardiacsurgery, con-cernabout adverse events,suchaschanges inthe gastric mucosal barrier, renal tubular function, and inhibition of platelet aggregation, limits the use of these analgesics. In astudy,indomethacin promoted reductionin morphine consumption by PCA and pain scores in the immediate postoperative period of cardiac surgery. There were no differences withpatientsreceiving placebo regarding tra-cheal extubation time or postoperative blood loss. The authors concludedthat the combination of indomethacin suppositories with morphine after cardiac surgery results inareductionofpainscoresandopioidconsumption with-outincreasing adverse events.35 Inanotherstudy,the use
ofdiclofenacreducedmorphineconsumptionforanalgesia aftercoronaryarterybypassgraft,viasternotomy,andthe samedidnotoccurwithketoprofenorindomethacinversus placebo.36
However, other authors obtained no benefit with anti-inflammatory drugs or with paracetamol in patients undergoingcardiacsurgery.36,37
Proparacetamol, a prodrug of acetaminophen, did not promotereductioninpainscores,oxycodoneconsumption, andpatientsatisfactionforanalgesiaaftercoronaryartery bypassgraftviasternotomy.37
Etodolac and diclofenac provided slightly better post-operative analgesia(assessedby theanalgesicvisualscale scoresandmorphineconsumption),andwithfeweradverse effects(assessedbyantiemetictherapy)thantramadolfor postoperativeanalgesia.38
Infiltrationwithlocalanesthetic
The pain after cardiac surgery is generally related to sternotomy,peakingduringthefirsttwodaysafterthe oper-ation. Due toadverse events associated with intravenous infusion of opioidsand anti-inflammatory drugs (gastroin-testinalbleedingandrenaldysfunction),optionalmethods forpostoperativeanalgesiawerethought.25
afterseveralsurgeriesinadditiontoheartsurgery.39 In36
patients undergoing cardiac surgery, two catheters were placed(oneinthesubfascialplaneabovethesternumand theotherabovethefasciaundertheskin)inthesternotomy incisionattheendofsurgery.Patientsreceived0.25% bupi-vacaine,0.5%bupivacaineorsalinesolutionbycontinuous infusion(4mLh−1)for48haftersurgery.Therewasno dif-ferenceinextubationtime.Therewasbetterpaincontrol and lower morphine consumption by PCA postoperatively with0.5%bupivacaine.Theauthorsconcludedthat contin-uousinfusionof0.5%bupivacaine(4mLh−1)iseffectiveto reducepostoperativepainseverityandneedfor supplemen-tationwithopioids,aswellastoimprovepatientsatisfaction (earlyambulationandreducedhospitalstay)aftercardiac surgery.40
Nerveblock
Therehasbeenincreaseduseofnerveblocktotreat post-operative pain due tothe rise in popularityof minimally invasivecardiacsurgeries,viaminithroracotomy.41,42
Spinalanalgesia
The techniques with opioids and/or local anesthetics provide reliable postoperative analgesia in patients after cardiacsurgery.43
The physicochemicalpropertiesofan opioiddetermine itsonsetof action, duration, andpower via subarachnoid route.1
Epidural and subarachnoid anesthesia and analgesia (with local anesthetics or opioids) can inhibit the stress response associated with surgical procedures. Another advantage in cardiac surgery is the heart and thoracic sympathectomy.44
Subarachnoid morphine has been used as an adjunct togeneral anesthesiaincardiac surgery, withbetter con-trol of postoperative pain and reducing venous opioid requirements.1 General anesthesia associated with
sub-arachnoidmorphineandclonidinereducedpainscoresand improvedqualityoflifeindicators.45Subarachnoidmorphine
improved pain control and pulmonary function tests, but there was no difference in extubation time.46
Subarach-noidmorphinefacilitatedtrachealextubationandprovided reliablepostoperative analgesia.47 Subarachnoidmorphine
providedsignificant analgesia postoperatively.48
Subarach-noidmorphineassociatedwithgeneralanesthesiareduced painscores, decreased opioidconsumption, andimproved pulmonaryfunctiontests,inadditiontominimizing respira-tory depression.49 In other studies,the authorsconcluded
that there was no benefit with the use of subarachnoid morphine.50
Subarachnoidbupivacaineattenuatedstressresponse.51
Epiduraladministrationoffentanylandbupivacaine pro-videdreliableanalgesiaaftercardiacsurgery.52 Therewas
noincreasedriskofhematomafollowingadministrationof bupivacaineor ropivacaine(bolus plusinfusion) for epidu-ral anesthesiain cardiac surgery.53 With bupivacaine and
fentanyl up to the third postoperative day, there was a reductioninICUlengthofstay,earlyextubation,lowerpain
scores,andbetterresultsin pulmonaryfunctiontestsand PaO2/FiO2ratio.54,55
Conclusions
Goodqualitypostoperativeanalgesiais importantbecause itcanpreventhemodynamic,metabolic,immunologicaland hemostatic changes, all of which have the potential to increasepostoperativemorbidity.
Patienteducationandtheestablishmentofprotocolsfor painmanagementareessential.
Alargenumberofapproachescanbeusedtotreatacute painafterthesurgery,includingepiduralor subarachnoid, paravertebralandintercostalblocks,intravenousopioidsvia PCA andadjuvants.However,systemic venousopioids are themainstayofpaintreatmentaftercardiacsurgery.Asa generalrule, theuse of a singletype of therapy totreat postoperativepainshouldbeavoided.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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