Brain protection in aortic arch surgery

78 Pages·2000·6.63 MB·English

by  Anttila, Vesa

BRAIN PROTECTION IN VESA
ANTTILA
AORTIC ARCH SURGERY
Department of Surgery,
University of Oulu
OULU 2000
VESA ANTTILA
BRAIN PROTECTION IN AORTIC
ARCH SURGERY
Academic Dissertation to be presented with the assent of
the Faculty of Medicine, University of Oulu, for public
discussion in Auditorium 1 of the University Hospital of
Oulu, on May 12th, 2000, at 12 noon.
OULUN YLIOPISTO, OULU 2000
Copyright © 2000
University of Oulu, 2000
Manuscript received: 10 April 2000
Manuscript accepted: 12 April 2000
Communicated by
Docent Matti Tarkka
Docent Tero Sisto
ISBN 951-42-5617-4 (URL: http://herkules.oulu.fi/isbn9514256174/)
ALSO AVAILABLE IN PRINTED FORMAT
ISBN 951-42-5616-6
ISSN 0355-3221 (URL: http://herkules.oulu.fi/issn03553221/)
OULU UNIVERSITY PRESS
OULU 2000
Anttila,Vesa,Brainprotectioninaorticarchsurgery
DepartmentofSurgery,UniversityofOulu,P.O.Box5000,FIN-90014UniversityofOulu,Finland
2000
Oulu,Finland
(Manuscriptreceived:10April2000)
Abstract
Retrogradecerebralperfusion(RCP)techniqueshavebeenadoptedinaorticarch surgeryforclinical
use.TheclearbenefitsofRCParethatitreducesembolic injuryandprolongsthepermissibleperiod
ofhypothermiccirculatoryarrest (HCA).Atthesametime,however,thereisagreatdealofevidence
accordingto whichRCPmaybeassociatedwithanincreasedriskoffluidsequestrationand cerebral
edema.InthecurrentstudyintermittentRCPwascomparedwith continuousRCPandHCAaloneto
clarifyifperiodicalRCPdecreasesfluid sequestration(I).
HCAisaneffectivemethodofcerebralprotection,butisassociatedwithlong cardiopulmonary
bypasstimes,andcoagulationdisturbances.Wetestedthe hypothesisthatdeephypothermicRCP
couldimprovecerebraloutcomeduring moderateHCA(IIandIII).
Glutamateexcitotoxicityplaysanimportantroleinthedevelopmentofischemic braininjury.
Thepurposeofthepresentstudywastodeterminetheefficacyof lamotrigine,aNa+channelblocker,
tomitigate cerebralinjuryafterHCA(IV). Achronicporcinemodelwasusedinthepresentseries
ofstudies.Hemodynamic, electrophysiologic,andmetabolicmonitoringwereperformeduntilfour
hours aftertheinstigationofrewarming.S-100(cid:1)wasmeasuredupto20hours. Daily behavioral
assessmentperformeduntildeathorelectivesacrificeontheseventh postoperativeday.
AftercontinuousRCPthemedianfluidsequestrationvolumewas145(0-250)ml comparedwith
-50(-100-0)mlafterintermittentRCP(p=0.04).Incomparisonof15(cid:2)CRCPtoHCAaloneduring
moderate25(cid:2)Chypothermia,5/6 animalsintheRCPgroupsurvivedsevendayscomparedwith2/6
intheHCAgroup (p=0.04).
The total histopathologic scores in the RCP(15(cid:2)C) group were lower than those for the
RCP(25(cid:2)C)groupduringmoderate25(cid:2)Chypothermia(p=0.04).EEGbursts wererecoveredbetter
intheRCP(15(cid:2)C)groupat3hoursafterthestartof rewarmingcomparedtoHCAgroup(p=0.05).
TherateofEEGburstrecoverywashigherinlamotriginetreatedanimals comparedtoplacebo
treatedanimalsafter4hoursduringtherewarming(p= 0.02).Amongtheanimalsthatsurvivedfor
7days,themedianbehavioralscore washigherinthelamotriginegroup(8)comparedwithcontrols
(7)(p=0.02).TheresultsindicatethatintermittentRCPdecreasestherateoffluid sequestrationafter
continuousRCP.ThecoldRCPatmoderatesystemic hypothermiaseemstoprovideabetterneuro-
logicaloutcomethanthatwith moderatetemperatureRCP,afindingsuggestingthatenhancedcranial
hypothermia isthemajorbeneficialfactorofRCP.TheNa+ channelblockerlamotrigine improves
neurologicaloutcomeafteraprolongedperiodofHCA.Inconclusion, tworefinementsintheRCP
conceptaretoadministeritatlowtemperaturesand iflongerperiodsofperfusionarenecessary,RCP
shouldbeapplied intermittently.
Keywords:retrogradeperfusion,hypothermiccirculatoryarrest,lamotrigine.