Artificial Organs

184 Pages·2009·7.63 MB·English

New Techniques in Surgery Series
Nadey Hakim (Ed)
Artificial Organs
1 3
Editor
NadeyHakim
RenalandTransplantServices
HammersmithHospital
London,UK
ISBN978-1-84882-281-8 e-ISBN978-1-84882-283-2
DOI10.1007/978-1-84882-283-2
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Foreword
Artificialorganshavecomealongwaysincethefirstdialysismachine,therotating
artificialkidney,wasinventedin1944byWillemJohanKolff,whoisknownasthe
‘‘father of artificial organs’’. At that time he met stiff resistance from his hospital
superiorsbuthispersistencepaidoffandamillionsavedliveshavebeenattributed
tohisfirstinvention.Hewasindeedthefirsttomixmedicineandengineering.An
artificialorganisanymachine,device,orothermaterialthatisusedtoreplacethe
functionsofafaultyormissingorganorotherpartsofthehumanbody.Somebody
parts are more of a challenge than others. The heart has one purpose and it is to
pumpblood;however,theliverhasbiochemicalandphysiologicalfunctionswhich
aredifficulttosimulate.Theimplantationofanartificialorganiscriticalbecauseof
thepatientlifedependencyontheartificialorgan itself.The treatment ofchoiceis
organtransplantation,however,transplantcandidatesfacealongwaitingtimeand
manydiewhileonthewaitinglist.Inadditiontherearepatientswhoareexcluded
from transplantation because of age or presence of other diseases. This book pre-
sentsanoverviewofthecurrentstateofknowledgeofartificialorgansincludingthe
liver, pancreas, kidney, heart, cochlea, skin, stem cells, composite tissue allograft,
andsphincters.Itisdesignedforstudentsinterestedinthefieldoforganreplacement
and bioartificial organs and it promotes an understanding of the designs and
materials required for successful implants. It fulfills a useful place in the medical
literature.Theeditorshavegatheredtogetherexpertsinavarietyofdifferentfields
both from the experimental and clinical aspects. Research in the field of artificial
organswillleadtoacloserrelationshipbetweenscienceandtechnologyandprovides
asteppingstoneforthefuture.
ProfessortheLordDarziofDenhamKBE
v
Contents
1 ManagementofMultiorganFailureAfterArtificialOrganImplantation
MichaelDevile,ParindPatelandCarlosMHGo´mez................. 1
2 ArtificialCirculatorySupport
JohnMulholland.............................................. 21
3 TheArtificialKidney
ChristopherKirwanandAndrewFrankel.......................... 39
4 LiverSubstitution
SambitSenandRogerWilliams ................................. 57
5 GlucoseSensorsandInsulinPumps:ProspectsforanArtificialPancreas
MartinPress................................................. 77
6 FromBasicWoundHealingtoModernSkinEngineering
L.C.Andersson,H.C.NettelbladandG.Kratz....................... 93
7 ArtificialSphincters
AustinObichereandIbnaufSuliman ............................. 107
8 CochlearImplant
GeorgeFayadandBehradElmiyeh............................... 133
9 StemCellsandOrganReplacement
NataˇsaLevicˇar,IoannisDimarakis,CatherineFlores,
EvangeliaIProdromidi,MyrtleYGordonandNagyAHabib.......... 137
10 CompositeTissueTransplantation:AStageBetweenSurgical
ReconstructionandCloning
EarlR.OwenandNadeyS.Hakim ............................... 165
Index........................................................... 179
vii
Contributors
LCAnderssonMDDrmedPhD AndrewFrankelMBBSMDBScFR
ConsultantPlasticSurgeon ConsultantNephrologist
AnelcaClinic WestLondonRenalandTransplant
SpecialistClinicforAesthetic Centre
andReconstructivePlasticSurgery ImperialCollegeHealthcareNHSTrust
London HammersmithHospital
UK London
UK
MichaelDevileBScMBBSMRCP(UK)
SpecialistTraineeRegistrar CarlosMHGo´mezLMSFRCAMD
inAnaesthesia EDICM
OxfordDeanery ConsultantinIntensiveCareMedicine
Oxfordshire andAnaesthesia
UK StMary’sHospital
ImperialNHSTrust
loannisDimarakisMRCS
London
DepartmentofSurgicalOncology
UK
andTechnology
MyrtleYGordonPhDDSc
FacultyofMedicine
DepartmentofHaematology
ImperialCollegeLondon
FacultyofMedicine
London
ImperialCollegeLondon
UK
London
MrBElmiyehMBBSMRCSDO-HNS UK
BasildonHospital
NagyAHabibChMFRCS
Basildon,Essex
DepartmentofSurgicalOncology
UK
andTechnology
MrGFayadMDFRCSFICS FacultyofMedicine
BasildonHospital ImperialCollegeLondon
Nethermayne London
Basildon UK
Essex
NadeyHakimKCJSJ,MD,PhD,FRCS,
UK FRCSI,FACS,FICS(Hon)
CatherineFloresPhD MaxThorekProfessorofSurgery
DepartmentofHaematology WestLondonRenalandTransplant
FacultyofMedicine Centre
ImperialCollegeLondon ImperialCollegeHealthcareNHSTrust
London London
UK UK
ix
x Contributors
ChristopherKirwanMD NorthSydney,NSW
SpecialistRegistrarRenalMedicine Australia
WestLondonRenalandTransplant
ParindPatelBScMBBSDMSFRCA
Centre
EDICM
HammersmithHospitalsNHSTrust
ConsultantinIntensiveCare
London
Medicine
UK
HammersmithHospital
GKratzMD ImperialNHSTrust
DepartmentofHandSurgery London
PlasticSurgeryandBurns UK
UniversityHospitalLinko¨ping
Linko¨ping DrMartinPressMAMScFRCP
Sweden ConsultantEndocrinologist
RoyalFreeHospital
NatasˇaLevicˇarPhD
London
DepartmentofSurgicalOncology
UK
andTechnology
FacultyofMedicine
EvangeliaIProdromidiPhDMSc
ImperialCollegeLondon
DepartmentofRenalMedicine
London
FacultyofMedicine
UK
ImperialCollegeLondon
JohnMulhollandBEngBScMSc London
ClinicalPerfusionScientist UK
LondonPerfusionScience
Westminster SambitSenMDMRCP
London DepartmentofGastroenterology
UK LutonandDunstableHospital
LewseyRoad
HCNettelbladM.D.PhD
Luton,Bedfordshire
AssociateProfessor
UK
AnelcaClinic
SpecialistClinicforAesthetic
MrIbnaufSulimanBSc(Hons)BM
andReconstructivePlasticSurgery
MRCS(Eng)
London
SpecialistRegistrar
UK
SouthEastThames
MrAustinObichereMBBSMDFRCS LondonDeanery
FRCS(Gem) London
ConsultantColorectalSurgeon UK
DepartmentofSurgery
RogerWilliamsCBEMDFRCP
UniversityCollegeLondonHospital
FRCSFRCPEFRACPFMedSci
London
FRCPI(Hon)FACP(Hon)
UK
ProfessorofHepatologyandConsultant
ProfessorEarlROwenAOMBBS Physician
(UniofSyd)MD(Lyon)DSc TheInstituteofHepatology
FRACSFRCSPICSFRCSE UniversityCollegeLondon
SpecialistinMicrosurgery,Hand London
andInfertilitySurgery UK
1
Management of Multiorgan Failure After Artificial
Organ Implantation
Michael Devile, Parind Patel and Carlos MH Go´mez
Cardiovascular Failure vessels,coagulopathy,reversinggastrointestinal
losses). The choice of fluid should be based on
The requirements of hemodynamic support in the fluid type that has been lost. For example,
bloodandbloodproductsshouldreplaceblood
patients with artificial organs follow the same
andcrystalloidshouldbeusedforvomitingand
principles as for any other patient. Ultimately
theneedforsuchsupportwillariseifthepatient dehydration. For mild to moderate blood loss
similartothatexpectedinaroutinerenaltrans-
isinshock.Thekeydisturbanceinshockisthe
plant crystalloid (2–3 times the lost blood
inability of the tissues and cells to obtain and
utilizeenoughoxygenfortheiraerobicrespira- volume) or colloid (1–2 times the lost blood
volume)isusuallyappropriate.
toryneeds,ultimatelyresultingincelldeath.
The debate of crystalloids versus colloid has
not been resolved; there exists numerous con-
Classification flicting trials, meta-analysis, and opinions. The
crystalloidsofchoiceinresuscitationarenormal
Shock is classified into four types based on the salineorlactatedRinger’ssolutionbecausetheir
underlying pathophysiological mechanism: osmolalityissimilartothatoftheintravascular
hypovolemic,cardiogenic,obstructive,anddis- volume.Inlarge-volumeresuscitation,however,
tributive.(Table1-1).Thepatientwithartificial excessive normal saline infusion may produce
organswillhaveahigherriskofalloftheabove hyperchloremic metabolic acidosis. As the
mechanisms at various stages of the peri and volume of distribution is much larger for crys-
postoperative process and extra vigilance is talloids than for colloids, resuscitation with
therefore necessary. The management of shock crystalloids requires more fluid to achieve the
should nevertheless follow basic critical care same end points and results in more edema.
principles: re-establishing perfusion to vital Crystalloids are less expensive. The current
organswhiletreatingtheunderlyingcondition. choiceofcolloidsincludeshydroxyethylstarch,
gelatins, and albumin all of which offer more
efficient intravascular volume expansion. The
administration of hydroxyethyl starch may
Hypovolemic Shock increasetheriskofacuterenalfailure,although
newer preparations appear to be less proble-
Thiscanoftenpresentasanemergency(dueto matic. Previous concerns of albumin resuscita-
massive hemorrhage for instance) or in a more tionleadingtoincreased mortality has recently
indolentmannerleadingtosloworganhypoper- beendispelledbytheSAFEstudyindicatingthat
fusion (due to a mismatch of fluid input and albuminadministrationwassafeandaseffective
output). Initial resuscitation should consist of ascrystalloid.Withanyfluidthereisinevitable
restoring intravascular volume, but more dilutionofblood(redbloodcells)andcoagula-
importantly reversing the cause (bleeding tion factors which needs to be considered.
N.Hakim(ed.),ArtificialOrgans,NewTechniquesinSurgerySeries4,DOI10.1007/978-1-84882-283-2_1, 1
(cid:2)Springer-VerlagLondonLimited2009
2 ArtificialOrgans
Table1-1. CausesofShock
Typeofshock Signs Hemodynamicvariables Causesrelevanttoartificialorgans
Hypovolemic Weakpulse -CVP/PAOP Massivehemorrhage
Narrowpulsepressure -CO Gastrointestinalfluidloss
Poorperipheralperfusion "SVR Diuresis
Cardiogenic Pulmonary/peripheraledema "CVP/PAOP Acutecoronarysyndrome
Galloprhythm,arrhythmias,&murmurs -CO Valvularheartdisease/dysrhythmias
Poorperipheralperfusion "SVR Cardiomyopathy
Obstructive Distendedneckveins "CVP/PAOP Tensionpneumothorax
Poorperipheralperfusion -CO Cardiactamponade
Respiratoryfailure "SVR Pulmonaryembolism
Distributive Pyrexia -CVP/PAOP Sepsis/SIRS
Warmandvasodilatedperipheries "CO Anaphylaxis
Edema -SVR Acuteliverfailure
Whatever the fluid, the therapy should be introduction of such measures has resulted in a
titrated to re-establish normal blood pressure, significantimprovementinischemiainducedcar-
pulse,cardiacoutput,andend-organperfusion. diogenicshockandmortality.
In terms of hemodynamic support, various
inotropic agents exist (Table 1-2) which act via
Cardiogenic Shock modulation of the sympathetic nervous system
either as direct agonists (dobutamine, dopexa-
Cardiogenic shock essentially refers to the fail- mine, dopamine, adrenaline) or indirectly by
ingpump.Thebloodflowtothevitalorgansand inhibiting phosphodiesterase III (e.g., milri-
peripheries is decreased due to an intrinsic none). Both mechanisms result in an increase
defect in cardiac function. This can be due to incAMP,anintracellularmodulatorofmyocar-
pathologyaffectingtheheartmuscle,rhythm,or dial contractility and arteriolar vasodilation.
thevalves. Oftentheinotropes,becauseofthearterialvaso-
The most common cause, both generally and dilatory effects or the concurrent systemic
within transplant medicine and artificial organs, inflammatory response syndrome that may
is myocardial ischemia. As in all types of shock, occur with cell death, are combined with vaso-
treatingmustbethepriority:incardiogenicshock pressors tomaintain overallperfusionpressure
this is achieved by reversing the ischemia (with in general and coronary artery perfusion pres-
angioplasty, thrombolysis, or emergency coron- sure in particular. Although the use of these
ary artery bypass grafting), correcting the dys- agentsisthoughtofasessentialtothecareofa
rhythmias, or simply supporting the circulation hemodynamicallyunstablepatient,thereisgreat
whileallowingtimeforthestunnedmyocardium variabilitywithincountriesandcentersastothe
to recover while preserving perfusion. The early optimumagent.Itisalsonotablethattheroleof
Table1-2. VasoactiveDrugsinSepsisandtheUsualHemodynamicResponses
Drug Dose Principalmechanism Cardiacoutput Bloodpressure SVR
Dobutamine 2–20mcg/kg/min Beta1 ++ + +
Dopamine 2–10mcg/kg/min Dopamine!Beta1!Alpha ++ + +
Dopexamine 0.25–4mcg/kg/min Dopamine+Beta2 ++ +/– –
Epinephrine 0.01–1mcg/kg/min Beta1+Beta2+Alpha ++ + +
Milrinone 0.3–0.7mcg/kg/min Phosphodiesteraseinhibitor + +/– –
Norepinephrine 0.01–1mcg/kg/min Alpha>beta1,beta2 + ++ ++
Phenylephrine 0.2–2.5mcg/kg/min Alpha + ++ ++
Vasopressin 0.4–0.10U/min V1receptor + + ++