anesthésie et chirurgies ophtalmiques · context sensitivity of ﬂuid volume kinetics is offered,...

Anesthésie et chirurgies ophtalmiques

Gilles Lacroix, M.D., FRCPC

Professeur adjoint

Université Laval

Février 2014

Présentation de cas

Anatomie

Pression intra-oculaire

Considérations anesthésiques

Options anesthésiques

Principales interventions chirurgicales

Plan

Nous ne discuterons pas des considérations:

1. pédiatriques

2. personnes âgées

Plan

CUO Centre Universitaire d’Ophtalmologie

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


Anatomie





!

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


Anatomie





!

orbite

œil

muscles

Paupières

Système lacrymal

Anatomie Plan

Anatomie Orbite

Anatomie Muscles oculaires

Anatomie


Anatomie





!

2/3 corps ciliaire

transport de Na actif

anhydrase carbonique

2 μl/min

1/3 filtration passive

PIO Formation de l’humeur aqueuse

entre 10 et 21 mmHg

variations quotidiennes

Élevé au matin

PIO Variations

Pressions

tonus musculaire

congestion veineuse

tumeur

Compliance de la sclère

Changement du contenu

humeur aqueuse

vaisseaux de la choroïde

tumeur

PIO Variations

Congestion veineuse

trendelenburg

collier cervical

toux

vomissements

Augmentation TA

laryngoscopie

douleur

PIO Variations

OPaq pression osmotique de l’humeur aqueuse

OPpl pression osmotique plasmatique

Pc pression capillaire

PIO Pression osmotique

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

PIO Abaissée

!agents d’inhalation

thiopental

propofol

étomidate *

narcotiques

benzodiazépines

neuroleptiques

!!

hyperventilation

hypothermie *

osmotiques: mannitol

acétazolamide

PIO Abaissée

!!

Kétamine: controverse

Atropine I.V.

PIO Inchangée

PIO Pancuronium

PIO Succinylcholine

PIO Succinylcholine

Augmentation de la PIO

débute après 1 min

pic d’action de 9 mmHg à 6 min

!

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 *

PIO Succinylcholine

Avantages

rapidité

conditions d’intubation

ventilation au masque de courte durée

Réduire l’augmentation PIO

lidocaïne

narcotiques

pré-curarisation

nitro, nidédipine, propanolol


Anatomie





!

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

Considérations Approche sécuritaire

Considérations Éviter d’augmenter la PIO

choix des médicaments

hypercarbie

contrôle de la TA

osmolarité

hydratation

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

[email protected]

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.

[email protected]

by guest on September 27, 2013

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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]

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

Considérations Réflexe oculo-cardiaque

Définition:

↓ RC de 10-20%

> 5 secondes

Déclenché:

traction des muscles

↑ PIO

pression sur le globe

Prévention ?

anticholinergiques

anest. régionale

Considérations Réflexe oculo-cardiaque

Incidence accrue:

hypercarbie

hypoxémie

pédiatrie

Traitement ?

cesser la stimulation

répétition entraîne une fatigue

atropine ou glycopyrrolate I.V.

lidocaïne infiltration


Anatomie





!

Options

Anesthésie locale

Anesthésie régionale

rétrobulbaire

péribulbaire

sub-Tenon

Anesthésie générale

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

Options Rétrobulbaire

!

Caractéristiques

anesthésie très intense

petit volume

début rapide

akinésie


Caractéristiques

aiguille 1¼ po

aiguille tranchante vs mousse

position œil en nasale

Complications

hématome

réflex oculo-cardiaque

Trauma nerf optique


!

Complications

rachi totale

injection artérielle

occlusion artère rétinienne

ponction du globe en postérieur

Écho

sécuritaire

œil axe > 26 mm

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

Options Sub-Tenon

Anesthésie

injection espace épisclérale

injection non douloureuse

rapide

aiguille ou canule mousse

peu de complication

Options Anesthésie générale

Indications

pédiatrie

collaboration difficile

immaturité

claustrophobie

bouge beaucoup

durée > 90 minutes

Intubation vs LMA

Awareness


Anatomie





!

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

Interventions Transplantation de cornée

Allogreffe

anesthésie générale

prélèvement < 18hres

cornée préservée 2 sem

œil ouvert


Interventions Trabéculectomie

Glaucome

échec du traitement médical

sub-Ténon anesthésie

fistule pour ↓ PIO

chambre antérieure vers

espace sous conjonctival


Interventions Énucléation

Variantes:

éviscération

exentération

Autres

implant après l’hémostase

durée 60 minutes

Souffrant

Interventions Vitrectomie

Décollement rétine

diabète

myopie

trauma

extraction cataracte

Vitrectomie

↓ traction sur la rétine

extraire le sang et les débris

Interventions Cerclage

Cerclage (Buckle)

Bulle de gase

SF6: 10-14 jours

C3F8: 5-7 semaines

danger du N2O

porter un bracelet

!Présentation Cas clinique

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


Questions

anesthésie et chirurgies ophtalmiques · context sensitivity of ﬂuid volume kinetics is offered,...

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