Colloids or crystalloid solutions? Is this (still) the question?
Anesthésie et chirurgies ophtalmiques · context sensitivity of fluid volume kinetics is offered,...
Transcript of Anesthésie et chirurgies ophtalmiques · context sensitivity of fluid volume kinetics is offered,...
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Anesthésie et chirurgies ophtalmiques
Gilles Lacroix, M.D., FRCPC
Professeur adjoint
Université Laval
Février 2014
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
Plan
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Nous ne discuterons pas des considérations:
1. pédiatriques
2. personnes âgées
Plan
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CUO Centre Universitaire d’Ophtalmologie
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30 ophtalmologistes
Interventions: cataracte, rétine et cornée
35 salles d’examen: 72 000 consultations/année
5 salles d’opération: 10 000 chirurgies/année
Recherche et enseignement
CUO Centre Universitaire d’Ophtalmologie
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
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Homme de 62 ans est passé sous son tracteur en fin d’après-midi. À l’urgence, le patient est conscient avec des douleurs à l’inspiration et une hémodynamie stable. L’investigation:
volet thoracique avec hémothorax: drain thoracique par l’urgentologue
massif facial: chirurgie prévue, intubation trans-pelvi-mandibulaire, durée minimale de 4 hres
œil ouvert: examen et exploration par l’ophtalmologiste, durée 1-2 hres
Nommer et discuter des considérations anesthésiques
Présentation Cas clinique
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Présentation Cas clinique
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
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orbite
œil
muscles
Paupières
Système lacrymal
Anatomie Plan
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Anatomie Orbite
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Anatomie Muscles oculaires
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Anatomie
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Anatomie
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
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2/3 corps ciliaire
transport de Na actif
anhydrase carbonique
2 μl/min
1/3 filtration passive
PIO Formation de l’humeur aqueuse
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entre 10 et 21 mmHg
variations quotidiennes
Élevé au matin
PIO Variations
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Pressions
tonus musculaire
congestion veineuse
tumeur
Compliance de la sclère
Changement du contenu
humeur aqueuse
vaisseaux de la choroïde
tumeur
PIO Variations
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Congestion veineuse
trendelenburg
collier cervical
toux
vomissements
Augmentation TA
laryngoscopie
douleur
PIO Variations
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OPaq pression osmotique de l’humeur aqueuse
OPpl pression osmotique plasmatique
Pc pression capillaire
PIO Pression osmotique
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Débit de réabsorption de l’humeur aqueuse A :
r rayon de l’espace de Fontana
Piop pression intraoculaire
Pv pression veineuse
η viscosité de l’humeur aqueuse
l longueur de l’espace de Fontana
PIO Humeur aqueuse
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PIO Abaissée
!agents d’inhalation
thiopental
propofol
étomidate *
narcotiques
benzodiazépines
neuroleptiques
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!!
hyperventilation
hypothermie *
osmotiques: mannitol
acétazolamide
PIO Abaissée
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!!
Kétamine: controverse
Atropine I.V.
PIO Inchangée
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PIO Pancuronium
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PIO Succinylcholine
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PIO Succinylcholine
Augmentation de la PIO
débute après 1 min
pic d’action de 9 mmHg à 6 min
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Extrusion du vitré
quelques cas ?
anesthésie légère
nécessite une énucléation
Mécanisme d’action
dilatation des vaisseaux de la
choroïde
baisse transitoire du drainage de
l’humeur aqueuse
pas de relation avec les muscles
oculaires *
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PIO Succinylcholine
Avantages
rapidité
conditions d’intubation
ventilation au masque de courte durée
Réduire l’augmentation PIO
lidocaïne
narcotiques
pré-curarisation
nitro, nidédipine, propanolol
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
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Approche sécuritaire
Éviter d’augmenter la PIO
Éviter les pressions extra-oculaires
Intervention sans mouvement
Considérations
Analgésie
Surveiller le réflexe oculocardiaque (OCR)
Minimiser les saignements
Émergence en douceur
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Considérations Approche sécuritaire
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Considérations Éviter d’augmenter la PIO
choix des médicaments
hypercarbie
contrôle de la TA
osmolarité
hydratation
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Considérations Éviter d’augmenter la PIO
Intraoperative fluids: how much is too
much?
M. Doherty1* and D. J. Buggy
1,2
1 Department of Anaesthesia, Mater Mis
ericordiae University Hospital, Universi
ty College Dublin, Ireland
2 Outcomes ResearchConsortium, Clevela
nd Clinic, OH, USA
* Corresponding author. E-mail: marga
Editor’s key points
† Both too little and excessive fluid
during the intraoperative period can
adversely affect patient outcome.
† Greater understandingof fluid
kinetics at the endothelial glycocalyx
enhances insight into bodily fluid
distribution.
† Evidence is mountingthat fluid
therapy guided by flow based
haemodynamic monitors improve
perioperative outcome.
† It is unclear whethercrystalloid or
colloid fluids or a combination of both
produce the optimal patient outcome
and in what clinical context.
Summary. There isincreasing evidenc
e that intraoperative fluid therapy
decisions may influence postoperativ
e outcomes. In the past, patients
undergoing majorsurgery were ofte
n administered large volumes of
crystalloid, basedon a presumption
of preoperative dehydration and
nebulous intraoperative ‘third space’ flu
id loss. However, positive perioperative
fluid balance, withpostoperative fluid-
based weight gain,is associated with
increased major morbidity. The conce
pt of ‘third space’fluid loss has been
emphatically refuted, and preopera
tive dehydrationhas been almost
eliminated by reduced fasting times a
nd use of oral fluids up to 2 h before
operation. A ‘restrictive’ intraoperative
fluid regimen, avoiding hypovolaemia
but limiting infusion to the minimu
m necessary, initially reduced majo
r
complications aftercomplex surgery, bu
t inconsistencies indefining restrictive
vs liberal fluid regimens, the type o
f fluid infused, and in definitions of
adverse outcomeshave produced co
nflicting results inclinical trials. The
advent of individualized goal-directed
fluid therapy, facilitated by minimally
invasive, flow-based cardiovascular m
onitoring, for example, oesophageal
Doppler monitoring, has improved
outcomes in colorectal surgery in
particular, and this monitor has b
een approved byclinical guidance
authorities. In thecontrasting clinical
context of relatively low-risk patients
undergoing ambulatory surgery, high-
volume crystalloidinfusion (20–30 m
l
kg21) reduces postoperative nausea a
nd vomiting, dizziness, and pain. This
review revises relevant physiology of
body water distribution and capillary-
tissue flow dynamics, outlines the
rationale behind the fluid regimens
mentioned above,and summarizes t
he current clinicalevidence base for
them, particularlythe increasing use
of individualized goal-directed fluid
therapy facilitatedby oesophageal Do
ppler monitoring.
Keywords: fluid therapy; fluids, i.v.
Fluid therapy is fundamental to the prac
tice of intraoperative
anaesthesia, but the precise type, amo
unt, and timing of its
administration is still the subject of exte
nsive debate. Almost
all patients presenting for general ana
esthesia will be admi-
nistered some formof i.v. fluid. Evidenc
e is increasing that
perioperative fluid therapy can affect im
portant longer-term
postoperative outcomes. Traditional pra
ctice involving intra-
operative administration of large cry
stalloid fluid volumes
to all patients arebeing challenged b
y recent evidence-
based, individualized goal-directed the
rapy (GDT). Although
many research questions about the b
alance of crystalloid
and colloid fluid remain unanswered, cu
rrent research is fo-
cusing on gaining greater understandin
g of fluid movement
at the vascular barrier and how surg
ery and anaesthetic
interventions can influence it in the int
raoperative period.
This review revisesthe relevant physio
logy underpinning
body fluid distribution and capillary fl
ow dynamics. It also
discusses the current evidence-based
rationale for using
various volumes and types of fluid ther
apy in different intra-
operative clinical contexts. Discussion
of preoperative fluid
resuscitation and continuing postoper
ative fluid therapyis
outside the scope of this review.
Physiology
Body water distribution
Water comprises 60% of the lean body
mass, !42 litres in a
70 kg man. Of this, about two-thirds
are intracellular (28
litres); therefore, extracellular volume
(ECV) comprises 14
litres. The extracellular compartment ca
n be further divided
into interstitial (11litres) and plasma
(3 litres) with small
amounts of transcellular fluids, for e
xample, intraocular,
gastrointestinal secretion, and cerebros
pinal fluid completing
the distribution (Fig. 1). These transcell
ular fluids are consid-
ered anatomically separate and not av
ailable for water and
solute exchange.1
British Journal of Anaesthesia 109 (1): 6
9–79 (2012)
Advance Access publication 1 June 20
12 . doi:10.1093/bja/aes171
& The Author [2012]. Published by Oxfo
rd University Presson behalf of the Bri
tish Journal of Anaesthesia. All rights
reserved.
For Permissions, please email: journals.
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Revised Starling equation and the glycocalyx modelof transvascular fluid exchange: an improved paradigmfor prescribing intravenous fluid therapyT. E. Woodcock 1* and T. M. Woodcock 21 Critical Care Service, Southampton University Hospitals NHS Trust, Tremona Road, Southampton SO16 6YD, UK2 The Australian School of Advanced Medicine, Macquarie University, NSW 2109, Australia
* Corresponding author. E-mail: [email protected]
Editor’s key points
† The classic Starlingprinciple does not holdfor fluid resuscitation inclinical settings.
† The endothelialglycocalyx layer appearsto have a major role influid exchange.
† A revision of Starlingincorporating theglycocalyx modelappears to explain betterthe responses seenclinically.
Summary. I.V. fluid therapy does not result in the extracellular volume distribution expectedfrom Starling’s original model of semi-permeable capillaries subject to hydrostatic andoncotic pressure gradients within the extracellular fluid. Fluid therapy to support thecirculation relies on applying a physiological paradigm that better explains clinical andresearch observations. The revised Starling equation based on recent research considersthe contributions of the endothelial glycocalyx layer (EGL), the endothelial basementmembrane, and the extracellular matrix. The characteristics of capillaries in varioustissues are reviewed and some clinical corollaries considered. The oncotic pressuredifference across the EGL opposes, but does not reverse, the filtration rate (the ‘noabsorption’ rule) and is an important feature of the revised paradigm and highlights thelimitations of attempting to prevent or treat oedema by transfusing colloids. Filtered fluidreturns to the circulation as lymph. The EGL excludes larger molecules and occupies asubstantial volume of the intravascular space and therefore requires a new interpretationof dilution studies of blood volume and the speculation that protection or restoration ofthe EGL might be an important therapeutic goal. An explanation for the phenomenon ofcontext sensitivity of fluid volume kinetics is offered, and the proposal that crystalloidresuscitation from low capillary pressures is rational. Any potential advantage of plasmaor plasma substitutes over crystalloids for volume expansion only manifests itself athigher capillary pressures.
Keywords: fluid therapy; intensive care
Twenty-five years ago, Twigley and Hillman announced ‘theend of the crystalloid era’. Using a simplified diagram ofplasma, interstitial and intracellular fluid compartments,and their anatomic volumes, they argued that colloidscould be used to selectively maintain the plasma volume.1
Plasma volume being about 20% of the extracellular fluid(ECF), it was presumed that the volume equivalence for re-suscitation from intravascular hypovolaemia would be ofthe order of 20 ml colloid to 100 ml isotonic salt solution(ISS). Moreover, it was presumed from Starling’s principlethat transfusion of hyperoncotic colloid solutions wouldabsorb fluid from the interstitial fluid (ISF) to the intravascu-lar volume. This simple concept of colloid for plasma volumeand ISS for ECF replacement has been continued and devel-oped.2 – 4 Two trials in critically ill patients have found thatover the first 4 days of fluid resuscitation, 100 ml ISS is as ef-fective as 62–76 ml human albumin solution5 or 63–69 mlhyperoncotic plasma substitute.6 In blunt trauma patientsduring the first day of resuscitation, 100 ml ISS was as effect-ive as 97 ml isosmotic plasma substitute, while in gunshot orstabbing victims, 100 ml was as effective as 67 ml.7 A trial ofpaediatric resuscitation practices in resource-poor facilities in
Africa demonstrated no advantages of bolus therapy withalbumin compared with ISS, and a survival advantage forslow ISS resuscitation without bolus therapy.8 A series ofvolume kinetics experiments have demonstrated that thecentral volume of distribution of ISS is much smaller thanthe anatomic ECF volume,9 and an editorial had to concludethat ‘Fluid therapy might be more difficult than you think’.10
This review attempts to reconcile clinical trial data andbedside experience of fluid therapy with recent advances inmicrovascular physiology to improve our working paradigmfor rational prescribing.
Starling’s principleFrom experiments injecting serum or saline solution into thehindlimb of a dog, Starling deduced that the capillaries andpost-capillary venules behave as semi-permeable mem-branes absorbing fluid from the interstitial space.11 Thework of Krooh and colleagues12 developed Starling’s principlein human physiology. With adoption of reflection coeffi-cient13 and pore theories,14 the familiar paradigm of raisedvenous pressure and reduced plasma protein concentration
British Journal of Anaesthesia 108 (3): 384–94 (2012)Advance Access publication 29 January 2012 . doi:10.1093/bja/aer515
& The Author [2012]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved.For Permissions, please email: [email protected]
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Considérations Intervention sans mouvement
2046 réclamations 1974-1987
3% (71) oculaires
30% (21) mouvement lors d’une chx ophtalmique
76% (16) anesthésie générale
24% (5) narcose
100% (21) cécité permanente
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Considérations Réflexe oculo-cardiaque
Définition:
↓ RC de 10-20%
> 5 secondes
Déclenché:
traction des muscles
↑ PIO
pression sur le globe
Prévention ?
anticholinergiques
anest. régionale
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Considérations Réflexe oculo-cardiaque
Incidence accrue:
hypercarbie
hypoxémie
pédiatrie
Traitement ?
cesser la stimulation
répétition entraîne une fatigue
atropine ou glycopyrrolate I.V.
lidocaïne infiltration
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
!
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Options
Anesthésie locale
Anesthésie régionale
rétrobulbaire
péribulbaire
sub-Tenon
Anesthésie générale
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Options Locale ou topique
Chirurgie de la cataracte
60% topique
Anesthésie topique: simple
Légère sédation
Désavantages
mouvements de l’œil
anxiété et inconfort du patient
Feu & oxygène Anesthesia Patient Safety Foundation www.apsf.org/resources_video.php
http://www.apsf.org/resources_video.php
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Options Rétrobulbaire
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Caractéristiques
anesthésie très intense
petit volume
début rapide
akinésie
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Options Rétrobulbaire
Caractéristiques
aiguille 1¼ po
aiguille tranchante vs mousse
position œil en nasale
Complications
hématome
réflex oculo-cardiaque
Trauma nerf optique
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Options Rétrobulbaire
!
Complications
rachi totale
injection artérielle
occlusion artère rétinienne
ponction du globe en postérieur
Écho
sécuritaire
œil axe > 26 mm
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Options Péribulbaire
!
Caractéristiques
plus facile
peu de complications
injection moins souffrante
grand volume
début plus lent
Anesthésiologistes
effectuent les blocs
efficience
péribulbaire un bon choix
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Options Sub-Tenon
Anesthésie
injection espace épisclérale
injection non douloureuse
rapide
aiguille ou canule mousse
peu de complication
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Options Anesthésie générale
Indications
pédiatrie
collaboration difficile
immaturité
claustrophobie
bouge beaucoup
durée > 90 minutes
Intubation vs LMA
Awareness
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Présentation de cas
Anatomie
Pression intra-oculaire
Considérations anesthésiques
Options anesthésiques
Principales interventions chirurgicales
!
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Interventions Extraction de cataracte
Technique extracapsulaire
anesthésie topique
incision 3 mm
phacoémulsification
portion postérieur de la capsule intacte
lentille pliable (silicone ou acrylique)
durée 15-60 minutes
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Interventions Transplantation de cornée
Allogreffe
anesthésie générale
prélèvement < 18hres
cornée préservée 2 sem
œil ouvert
durée 90-120 minutes
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Interventions Trabéculectomie
Glaucome
échec du traitement médical
sub-Ténon anesthésie
fistule pour ↓ PIO
chambre antérieure vers
espace sous conjonctival
durée 30-60 minutes
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Interventions Énucléation
Variantes:
éviscération
exentération
Autres
implant après l’hémostase
durée 60 minutes
Souffrant
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Interventions Vitrectomie
Décollement rétine
diabète
myopie
trauma
extraction cataracte
Vitrectomie
↓ traction sur la rétine
extraire le sang et les débris
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Interventions Cerclage
Cerclage (Buckle)
Bulle de gase
SF6: 10-14 jours
C3F8: 5-7 semaines
danger du N2O
porter un bracelet
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!Présentation Cas clinique
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Homme de 62 ans est passé sous son tracteur en fin d’après-midi. À l’urgence, le patient est conscient avec des difficultés respiratoire et une hémodynamie stable
volet thoracique avec hémothorax
massif facial
œil ouvert
Présentation Cas clinique
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Questions