RevBrasAnestesiol.2017;67(5):535---537
REVISTA
BRASILEIRA
DE
ANESTESIOLOGIA
PublicaçãoOficialdaSociedadeBrasileiradeAnestesiologiawww.sba.com.br
CLINICAL
INFORMATION
Hypotension
and
bradycardia
before
spinal
anesthesia
Carlos
Javier
Shiraishi
Zapata
HospitalESSALUDTalara,ServiciodeCentroQuirúrgicoyAnestesiología,Piura,Peru
Received26November2014;accepted2December2014 Availableonline23November2015
KEYWORDS
Hypotension; Bradycardia; Vagaltone; Antihypertensives drugs
Abstract Ireportacaseofhypotensionandbradycardiabeforespinalanesthesiainapregnant
womanwithmildtomoderatehypertensiontreatedwithnifedipineandmethyldopa,scheduled
foranelectivecesareandelivery.Shehadthehistoryofneurally-mediatedsyncopes.Twomain factors(increasedvagaltoneandadverseeffectsofantihypertensivedrugs)couldexplainthe hypotensionandbradycardiabeforespinalanesthesia.Monitoringallowedrecognizingthe prob-lemandcorrectedit.Thus,itwasavoidedadisasterinanesthesia,ashemodynamicchanges afterspinalanesthesia,theywouldhavejoinedtoprevioushypotensionandbradycardia,which wouldhavecausedevenacardiacarrest.
©2015SociedadeBrasileiradeAnestesiologia.Publishedby ElsevierEditoraLtda.Thisisan openaccessarticleundertheCCBY-NC-NDlicense( http://creativecommons.org/licenses/by-nc-nd/4.0/).
PALAVRAS-CHAVE
Hipotensão; Bradicardia; Tônusvagal; Medicamentos anti-hipertensivos
Hipotensãoebradicardiaantesdaraquianestesia
Resumo Relato de um caso de hipotensãoe bradicardia antesda raquianestesia em uma
mulher grávidacomhipertensão leveamoderadatratadacomnifedipinaemetildopa,
pro-gramadaparapartocesárioeletivo.Apacienteapresentavahistóriadesíncopesneuralmente mediadas.Doisfatoresprincipais(aumentodotônusvagaleefeitosadversosdemedicamentos anti-hipertensivos)poderiamexplicarahipotensãoebradicardiaantesdaraquianestesia.O
monitoramentopermitiureconheceroproblemaecorrigi-lo.Assim,foievitadoum desastre
em anestesia;assimcomo asalterac¸õeshemodinâmicasapósaraquianestesia,essesfatores teriamsejuntadoàhipotensãoebradicardiaanterior,oquepoderiatercausadoinclusiveuma paradacardíaca.
©2015SociedadeBrasileiradeAnestesiologia.PublicadoporElsevierEditoraLtda.Este ´eum
artigo OpenAccess sobumalicenc¸aCCBY-NC-ND(
http://creativecommons.org/licenses/by-nc-nd/4.0/).
E-mail:shiraishi52@hotmail.com
http://dx.doi.org/10.1016/j.bjane.2014.12.008
536 C.J.ShiraishiZapata
Introduction
Awiderangeofantihypertensivedrugshavebeenproposed to decrease the blood pressure in hypertensive pregnant women, and each of them has different side effects and potentialadverseeffects.Thereisnoconsensusaboutthe definitionofhypertensive pregnancydisordersandseveral classifications have been suggested. Variations in the sys-temsforclassificationarelargelyaccordingtowhichvalues ofblood pressure areconsidered abnormal. Nevertheless, thereiscurrentlyanagreementregardingtheexistenceof fourcategories which includegestational hypertension or pregnancy-inducedhypertension.1
A case of hypotension and bradycardia before spinal anesthesia in a pregnant woman with mild to moderate hypertension,scheduled foran electivecesarean delivery, isreportedwiththepatient’sandtheHospitalEthics Com-mittee’swrittenconsent.
Case
report
A34-year-oldpatientwasadmittedfourdaysbeforesurgery, witha gestationalage of 37 weeks by date of last men-struationandpregnancy-inducedhypertension.Shehadtwo previousCaesariansections(in2007and2011)whichwere performed with spinal anesthesia without complications. Shewassufferingfromintermittentbronchialasthma,with afinalepisodeintheyear2013;andreportedsomeepisodes ofvasovagalandorthostaticsyncopesindifferenttimesof herlife. Her weightand height were 98.8kg and 1.65m, respectively.Herphysical conditionwasgrade2according toAmericanSociety Anesthesiologistsphysical status clas-sification; she was assigned to class 2 of Goldman index of cardiac risk and had a normal electrocardiogram. The laboratory analyses showeda hemogram withnormal val-ues(hematocrit41%,platelets237,000mm3);thevaluesof glucose,creatinine,urea,andaminotransferaseswere nor-maltoo.The value ofproteins ina 24h urinewas126mg (3000mLofurinaryvolume).
Whenthepatientwashospitalized,fourdaysbeforethe surgery,herbloodpressurewas140/80mmHgandtheheart rate (HR) was 79beats per minute (bpm). An antihyper-tensivetreatmentof10mgofnifedipinewasadministered orallyt.i.d.Adaylaterwasaddedmethyldopa500mgorally t.i.d.Sheswallowedfooduntil5p.m.andreceivedthelast doseofantihypertensivedrugsupto22hofthepreviousday tothecesareansection.
The day of surgery thepatient didnot receive antihy-pertensive treatment, and the last control of vital signs at 7 a.m. wasregistered as normal in the hospitalization area. Furthermore, she received a bolus of physiologi-cal saline serum (500mL). None of the previous controls of blood pressure was lesser than 110/70mmHg until two days before the cesarean section. However the day before,she registeredablood pressureof90/60mmHgat 1p.m.
When the patiententered the operating room at 9:40 a.m.,shewaslucidandoriented;nevertheless,palenessand anxietywereobserved.Anon-invasivebloodpressure(NIBP) of73/35mmHgwasmeasuredinthemulti-parameters mon-itor,HRof 37bpmand a breathingrate of 18breaths per
minute. The results were corroborated by manual mea-surements. The patient wasasked if she had taken some medicinewhichshedenied.
The patient receivedan infusion of 500mL of isotonic salinesolution;nextaNIBPof80/42mmHgwasmeasured. After she wasgiven 1000mL, her NIBP was 92/64mmHg. Finally,shegaveavolumeof1500mLandherbloodpressure rose to 110/60mmHg. Atropine (0.5mg) was given intra-venously,whichmadeherHRgoupto82bpm.At10am,I proceededtoadministerspinalanesthesiacontaining10mg of hyperbaric Bupivacaine and 10gr of fentanyl, at the leveloftheL3---L4spacewithneedletypeQuinckeno.26. Weplaced thepatientindorsaldecubitus with15◦ ofleft
inclination fromthe surgical table.Fifteen minutes after, thesurgery startedwithaNIBP of90/42mmHgandHRof 114bpm.Tenminutesaftertherewasthebirthofthefetus withgoodApgarscores;inthistimeitwascontrolledaNIBP of79/40mmHg,soIstartedintravenousinfusionof3mgof Etilefrineandtwobolusof1mgofthesamedrugwiththat theNIBProseto130/60mmHg.
Nootherproblems occurredin theremainingperiodof the surgery.The patient leftat 11:05withisotonic saline solution(totalinfusedvolumeof2500mL)and20IUof Oxy-tocininfusedintravenously,withoutanykindofvasopressor, NIBP of 114/64mmHg, HR 99bpm, oxygen saturation on roomair96%andbreathingrateof16bpm.
Discussion
WhenIinvestigatedthecausesofhypotensionand bradycar-diaattheentrancetotheoperatingroom,anaphylaxiswas discardedfirst,becauseithasnothadprovidedany medica-tionbeforeoperatingroom;then,wasconsideredanexcess vagalbecauseshehadhadsomeepisodesoftransientloss ofconsciousnesstone,eventhoughshewasawarewhenshe arrivedtotheoperatingroom.Nonetheless,therearesome interesting pointsabout the adverse effectsof antihyper-tensivedrugs,too.
Nifedipine,ascalciumantagonistantihypertensive,has a short terminal half-life of 1.9h for a 10mg tablet, so multipledosesarerequiredtoachievetheeffective concen-tration (78g/lt.); being the minimum concentration to decrease diastolicpressureof 10---15g/lt.2 Inrelation to orthostaticsyncopes,ithasbeen describedfourcauses of compensatory failure. One of them is the attenuation of vasoconstrictor response to sympathetic stimulation; this attenuated response is primarily caused by the adminis-tration of vasodilative agents among which are calcium antagonistsasnifedipine.3
Methyldopa (␣-methyl-3,4-dihidroxi-l-phenylalanine),
Hypotensionandbradycardiabeforespinalanesthesia 537
insidethe operatingroom.Although themaximumplasma concentrations occur after 2---3h, the maximum effect is delayed6---8h,andasingledose usuallylasts almost24h, which allows providing a dosage one to two times per day.5---7Therefore,inthiscase,methyldopashouldnothave been supplied threetimes per day and couldhave begun withonelowerdose; evenmoreconsidering that shewas alreadyreceivingnifedipine.
Among themostcommonadverse effectsfrom methyl-dopaincludefatigue,xerostomia,decreasedlibido, parkin-sonian signs, hyperprolactinemia, hepatotoxicity, intense bradycardia and sinoatrial asystole, sedation and even depression in higher doses.8,9 Hypotension has also been reportedasfrequentadverse effect,especiallyinyounger patients,lightersubjects,patientswithimpairmentofrenal functionorinthosetakinghighdailydoses.10However,ithas a safetyprofile in thetreatment of gestational hyperten-sion,currentlyreachingtoconstitutethedrugofchoicefor thetreatmentofnon-severehypertensioninthispopulation, usedindifferentregionsaroundtheworld.5,11---13
Inconclusion,twomainfactorscanbeobservedinthis case, in oneside ahistory of increasedvagal tone of the patient and in the other, the adverse effects of previous medicaltherapy.Bothof themaffectedtheplanned anes-thetic scheme for an elective surgery. Monitoring had an importantrolebecauseitallowedrecognizingtheproblem andcorrected it. Thus,it wasavoided adisaster in anes-thesia, ashemodynamicchanges thatoccur afteraspinal anesthesiain a pregnant woman,they wouldhave joined to previous hypotension and bradycardia, which probably wouldhavecausedevenacardiacarrest.
Conflicts
of
interest
Theauthordeclaresnoconflictsofinterest.
Acknowledgements
Assistancewiththecase:theauthorwouldliketoexpresshis sinceregratitudetoJacparE.Diaz,MD,forhishelpwiththe
references;andtoKatherineSandoval,InternofMedicine, forherhelptomakethehomeinterviewofthepatient.
References
1.Abalos E, Duley L, Steyn DW. Antihypertensive drug
ther-apy for mild to moderate hypertension during pregnancy.
CochraneDatabaseSystRev.2014,http://dx.doi.org/10.1002/ 14651858.CD002252.pub3.Art.No.CD002252.
2.KirstenR,NelsonK,KirstenD,etal.Clinicalpharmacokinetics ofvasodilators.PartI.ClinPharmacokinet.1998;34:457---82.
3.Iwase S, Nishimura N, Mano T. Role of sympathetic nerve
activityintheprocessoffainting.FrontPhysiol.2014;5:343,
http://dx.doi.org/10.3389/fphys.2014.00343.eCollection2014. 4.Oates JA, Gillespie L, Udenfriend S, et al. Decarboxylase
inhibition and blood pressure reduction by ␣-methyl-3,4-dihydroxy-dl-phenylalanine.Science.1960;131:1890---1.
5.HoffmanBB.Therapyofhypertension.In:Goodman&Gilman’s thepharmacologicalbasisoftherapeutics.11thed.NewYork: McGraw-HillCompaniesInc.;2006.p.845---68.
6.VanZwietenPA,ThoolenMJ,TimmermansPB.Thehypotensive activityofmethyldopa,clonidine,and guanfacine. Hyperten-sion.1984;6Pt2:II28---33.
7.SicaDA.Centrallyactingantihypertensiveagents:anupdate.J ClinHypertens(Greenwich).2007;9:399---405.
8.Engelman K. Side effects of sympatholytic antihypertensive drugs.Hypertension.1988;11Pt2:II30---3.
9.MichelT,HoffmanBB.Treatmentofmyocardialischemiaand hypertension. In: Goodman & Gilman’s the pharmacological basisoftherapeutics.12thed.NewYork:McGraw-Hill Compa-niesInc.;2011.p.745---88.
10.Lawson DH, Gloss D, Jick H. Adverse reaction to methyl-dopa withparticularreference to hypotension. AmHeart J. 1978;96:572---9.
11.AlKhajaKA,SequeiraRP,AlkhajaAK,etal.Drugtreatmentof hypertensioninpregnancy:acriticalreviewofadultguideline recommendations.JHypertens.2014;32:454---63.
12.XieRH,GuoY,KrewskiD,etal.Trendsinusingbeta-blockers and methyldopa for hypertensivedisordersduringpregnancy ina Canadianpopulation.EurJObstetGynecolReprod Biol. 2013;171:281---5.
