perioperativevisual loss associated with spine …...perioperativevisual loss associated with spine...
TRANSCRIPT
PerioperativeVisual Loss
Associated with Spine Surgery
Agina
AginaM. Kempen, CRNA
M. Kempen, CRNA
Chief Nurse Anesthetist
Chief Nurse Anesthetist
St. Clair Hospital
St. Clair Hospital
Pittsburgh, PA
Pittsburgh, PA
Website/Resources:
Website/Resources:
www.asaclosedclaims.org
Miller
Miller ’’s Anesthesia Sixth Edition
s Anesthesia Sixth Edition
Anesthesiology 2006; 104:1319
Anesthesiology 2006; 104:1319-- 2828
Introduction
��Rare, estimated at 0.0008% to 0.003%.
Rare, estimated at 0.0008% to 0.003%.
��May be under
May be under-- reported due to litigation.
reported due to litigation.
��Questionably on the rise.
Questionably on the rise.
��In 1999 ASA established Postoperative
In 1999 ASA established Postoperative
Visual Loss Database with 23 patients.
Visual Loss Database with 23 patients.
��Will focus on varying degrees of visual
Will focus on varying degrees of visual
loss, including blindness, following spine
loss, including blindness, following spine
surgery in the prone position.
surgery in the prone position.
Anatomy of the Visual Pathway
��Cornea/Lens
Cornea/Lens ----focus light on retina
focus light on retina
��IrisIris----controls amount of light
controls amount of light
��Ciliary
Ciliarybody
body----produces aqueous humor
produces aqueous humor
��3 chambers:
3 chambers:
��Anterior
Anterior ----cornea to iris
cornea to iris
��Posterior
Posterior ----iris to
iris to ciliary
ciliarybody to vitreous
body to vitreous
��Vitreous
Vitreous ----contains jelly
contains jelly-- like vitreous humor
like vitreous humor
��Layers:
Layers:
��Sclera,
Sclera, Choroid
Choroid, Retina
, Retina
Retina
��Outer retina contains photoreceptors, rods and cones.
Outer retina contains photoreceptors, rods and cones.
��Rods: night vision and motion detection
Rods: night vision and motion detection
��Cones: central reading and color vision
Cones: central reading and color vision
��Inner retina contains neurons for transmission of
Inner retina contains neurons for transmission of
visual information to the brain
visual information to the brain
Fovea Centralis(Macula)
��Retina thins
Retina thins
��No support structures, few nerve fibers, no rods
No support structures, few nerve fibers, no rods
��Consists entirely of cones
Consists entirely of cones----suited for color and acute
suited for color and acute
vision.
vision.
(Williams EL: AnesthAnalg1995;80:1018-29)
Ocular Blood Supply
��Ophthalmic artery
Ophthalmic artery----
supplies most of eye
supplies most of eye
��Ocular branches
Ocular branches----
��Central Retina Artery
Central Retina Artery
(CRA)
(CRA)
��Posterior
Posterior Ciliary
CiliaryArtery
Artery
Trunks (PCA)
Trunks (PCA)
��CRA sends branches to
CRA sends branches to
supply retina and optic
supply retina and optic
nerve (ON).
nerve (ON).
��Main
Main PCAs
PCAsdivide into
divide into
short
short PCAs
PCAs(( sPCAs
sPCAs ).).
��sPCAs
sPCAssupply posterior
supply posterior
choroid
choroidand portion of the
and portion of the
ON.
ON.
Ocular Blood
Supply
��Circle of
Circle of Zinn
Zinn-- Haller
Haller
��formed by the medial and
formed by the medial and
lateral
lateral sPCAs
sPCAsaround the ON.
around the ON.
��from here are derived the
from here are derived the pial
pial
and
and choroid
choroidbranches.
branches.
��subject to anatomic variation
subject to anatomic variation
��complete in 77% of humans
complete in 77% of humans
Watershed
Zones
��PCA supply is subject to individual variation.
PCA supply is subject to individual variation.
��PCAs
PCAsare end
are end-- arteries without
arteries without anastamosis
anastamosis ..
��Region between each end
Region between each end-- artery supply is a
artery supply is a
watershed zone.
watershed zone.
��Hypotension could lead to poor perfusion.
Hypotension could lead to poor perfusion.
Posterior Optic Nerve
��Blood supply
Blood supply-- pial
pial
arteries and branches
arteries and branches
of CRA.
of CRA.
��Anatomic variation
Anatomic variation
can influence
can influence
watershed geography
watershed geography
��Blood flow less than
Blood flow less than
the anterior ON.
the anterior ON.
(Williams EL: AnesthAnalg1995;80:1018-29)
ChoroidalVessels
��Provide oxygen to outer layers of retina, where
Provide oxygen to outer layers of retina, where
photoreceptors are located.
photoreceptors are located.
��6060-- 80% of retinal oxygen supply is from
80% of retinal oxygen supply is from choroid
choroid..
��Blood flow is high (2000 ml/min/100g) and oxygen
Blood flow is high (2000 ml/min/100g) and oxygen
extraction is low (3%).
extraction is low (3%).
��Relatively large oversupply of perfusion.
Relatively large oversupply of perfusion.
Retinal Vessels
��Nourishes the inner 2/3 of the retina.
Nourishes the inner 2/3 of the retina.
��Blood flow is low (40
Blood flow is low (40-- 100 ml/min/100g) and extraction
100 ml/min/100g) and extraction
is high (38%).
is high (38%).
��Relatively limited blood flow to neuronal ganglia cells
Relatively limited blood flow to neuronal ganglia cells
that have a low tolerance to ischemia.
that have a low tolerance to ischemia.
(Williams EL:
(Williams EL: Anesth
AnesthAnalg
Analg1995;80:1018
1995;80:1018-- 29)
29)
Retina and Choroid
��Autroregulates
Autroregulateswith changes in arterial
with changes in arterial
blood pressure, oxygen and CO2 tension.
blood pressure, oxygen and CO2 tension.
��Inhalation of
Inhalation of hypercapneic
hypercapneicgas increases
gas increases
blood flow.
blood flow.
��Atherosclerosis is associated with defective
Atherosclerosis is associated with defective
autoregulation
autoregulation..
��Blood flow may be altered with anesthesia
Blood flow may be altered with anesthesia
and surgery.
and surgery.
Visual Loss: Symptoms
��Blurry vision to complete blindness
Blurry vision to complete blindness
��Unilateral or bilateral
Unilateral or bilateral
��Complete or partial loss of light
Complete or partial loss of light
��Unfamiliar to most anesthesia providers
Unfamiliar to most anesthesia providers
��May be attributed to anesthetics, eye
May be attributed to anesthetics, eye
ointment.
ointment.
��All patients with symptoms should receive
All patients with symptoms should receive
an
an opthalmologic
opthalmologicexam.
exam.
Central Retinal Artery Occlusion
��Decreases blood flow to entire retina.
Decreases blood flow to entire retina.
��Mechanisms of injury:
Mechanisms of injury:
��1. Emboli
1. Emboli----incidence of
incidence of microemboli
microemboliafter OHS is
after OHS is
almost 100%.
almost 100%.
��2. 2. Atheromatous
Atheromatousdisease
disease
��3. Inflammation, such as
3. Inflammation, such as arteritis
arteritis
��4. Vasospasm
4. Vasospasm
��5. Increased IOP and/or local venous congestion
5. Increased IOP and/or local venous congestion
resulting in low retinal perfusion pressure:
resulting in low retinal perfusion pressure:
��I.e. external pressure on the eyes in the prone position or
I.e. external pressure on the eyes in the prone position or
the surgical
the surgical ligation
ligationof the external jugular veins.
of the external jugular veins.
CRAO Resulting from Low Retinal
Perfusion Pressure
��RPP=MAP
RPP=MAP --IOP
IOP --CVP
CVP
��Increased risk with deliberate hypotension/prone
Increased risk with deliberate hypotension/prone
��Improper positioning of head
Improper positioning of head----compression of
compression of
ocular and
ocular and peri
peri --orbital contents.
orbital contents.
��Increased incidence:
Increased incidence:
��Altered facial anatomy
Altered facial anatomy
��Osteogenesis
OsteogenesisImperfecta
Imperfecta
��Exophthalmos
Exophthalmos
��Asian descent with lower nasal bridge
Asian descent with lower nasal bridge
��In older reports, use of horseshoe headrest.
In older reports, use of horseshoe headrest.
HeadproneRP3
Eye Injury Issue Leads to New Protective
Helmet Device and Research on Face
Pressures from Prone Positioning on OR
Table
Normal Fundoscopy
��Normal Optic
Normal Optic
Disk
Disk
��Normal Vessels
Normal Vessels
without
without
Hemorrhage
Hemorrhage
��Healthy Yellow
Healthy Yellow--
Red Retina
Red Retina
CRAO Fundoscopy
��Retinal pallor
Retinal pallor --
ischemia
ischemia
��Narrowed retinal
Narrowed retinal
arterioles
arterioles
��Cherry
Cherry-- red spot in the
red spot in the
fovea
fovea-- retina is
retina is
ischemic and
ischemic and
underlying
underlying choroid
choroidis is
visible.
visible.
Central Retinal Artery Occlusion
��Neck/nasal surgery
Neck/nasal surgery-- highest proportion of CRAO
highest proportion of CRAO
due to direct vascular damage or spasm
due to direct vascular damage or spasm
��Other Symptoms:
Other Symptoms:
��Possible Ocular Muscle Impairment
Possible Ocular Muscle Impairment
��Facial or
Facial or Periorbital
PeriorbitalEdema
Edema
��Prognosis:
Prognosis:
��In most cases, permanent loss of vision
In most cases, permanent loss of vision
��Treatment:
Treatment:
��No satisfactory treatment
No satisfactory treatment ----ocular massage, IV
ocular massage, IV
Diamox
Diamox, 5% CO2 inhalation, localized hypothermia
, 5% CO2 inhalation, localized hypothermia
Central Retinal Artery Occlusion
��Prevention
Prevention
��Avoid compression of globe
Avoid compression of globe----surgeon
surgeon’’ s arm
s arm
��If prone, use of padded headrest with eye/nose
If prone, use of padded headrest with eye/nose
opening
opening
��If head does not fit in foam headrest, consider
If head does not fit in foam headrest, consider
securing head in pins.
securing head in pins.
��Intermittent exam of eyes in prone position
Intermittent exam of eyes in prone position
��Position head straight down in neutral position.
Position head straight down in neutral position.
��Limited usage of deliberate hypotension with
Limited usage of deliberate hypotension with
prone
prone Trendelenberg
Trendelenberg
��““Air Maneuvers
Air Maneuvers ””and TEE during CP Bypass
and TEE during CP Bypass
Ischemic Optic Neuropathy (ION)
��Occurs after surgery or non
Occurs after surgery or non-- surgical bleeding
surgical bleeding
��Develops spontaneously
Develops spontaneously
��Leading cause of sudden visual loss in patients
Leading cause of sudden visual loss in patients
>50 years old
>50 years old
��Can be either
Can be either arteritic
arteriticor non
or non-- arteritic
arteritic
��Two types:
Two types:
��1.Anterior Ischemic Optic Neuropathy (AION)
1.Anterior Ischemic Optic Neuropathy (AION)
��more common and more extensively studied
more common and more extensively studied
��2.Posterior Ischemic Optic Neuropathy (PION)
2.Posterior Ischemic Optic Neuropathy (PION)
Ischemic Optic Neuropathy
(Williams EL: AnesthAnalg1995;80:1018-29) ��AION
AION----
��caused by interruption
caused by interruption
of blood supply to
of blood supply to
anterior portion of
anterior portion of
optic nerve.
optic nerve.
��PION
PION----
��produced by decreased
produced by decreased
oxygen delivery to the
oxygen delivery to the
posterior,
posterior, retrolaminar
retrolaminar
portion of the optic
portion of the optic
nerve.
nerve.
ArteriticIschemic Optic Neuropathy
��Anterior
Anterior
��Inflammatory process due to temporal
Inflammatory process due to temporal
arteritis
arteritis ----biopsy to confirm.
biopsy to confirm.
��Majority of patients have had flu
Majority of patients have had flu-- like
like
symptoms.
symptoms.
��Must emergently be treated with steroids.
Must emergently be treated with steroids.
��Posterior
Posterior
��Very rare inflammatory process
Very rare inflammatory process
��Found with systemic lupus, sickle cell
Found with systemic lupus, sickle cell
disease.
disease.
Causes of PerioperativeAnterior
Ischemic Optic Neuropathy
��Anatomic and physiologic variations in the
Anatomic and physiologic variations in the
circulation of the optic nerve
circulation of the optic nerve
��Underperfused
Underperfusedareas of the anterior optic nerve
areas of the anterior optic nerve
are found especially in patients with increased
are found especially in patients with increased
IOP and systemic hypotension.
IOP and systemic hypotension.
��Small optic disk may play role in AION
Small optic disk may play role in AION
susceptibility
susceptibility
��Axons that pass through narrowed opening into
Axons that pass through narrowed opening into
eye are prone to injury.
eye are prone to injury.
Surgeries in Which AION and PION
Have Occurred:
��Supine Position:
Supine Position:
��Cardiac and Cardiovascular Surgery *
Cardiac and Cardiovascular Surgery *
��Abdominal, OB and
Abdominal, OB and Gyn
GynSurgery
Surgery
��Head and Neck Surgery *
Head and Neck Surgery *
��Lateral Position:
Lateral Position:
��Thoracotomy
Thoracotomy
��Hip Surgery
Hip Surgery
��Prone Position:
Prone Position:
��Spine Surgery *
Spine Surgery *
Fundoscopyof Acute Anterior Ischemic
Optic Neuropathy
��Early stages
Early stages----Optic
Optic
disk swelling (edema)
disk swelling (edema)
and a splinter
and a splinter
hemorrhage at the
hemorrhage at the
optic disk margin
optic disk margin
Acute Anterior ischemic optic neuropathy
www.asaclosedclaims.org
Fluoresceinfundus
angiograms during
the early stages of
AION, showing no
circulation in parts
of the choroidand
optic disc (dark
areas correspond
to absence of
filling by
fluoresceindye).
Posterior Ischemic Optic Neuropathy
��Area not as well
Area not as well --vascularized
vascularizedas the anterior
as the anterior
portion of optic nerve (ON).
portion of optic nerve (ON).
��Caused by low
Caused by low-- flow state from systemic
flow state from systemic
hypotension; emboli or venous stasis could
hypotension; emboli or venous stasis could
contribute to PION.
contribute to PION.
��Initial period can be symptom
Initial period can be symptom-- free.
free.
��Initial normal
Initial normal fundoscopy
fundoscopy..
��Within 6 weeks, optic disk atrophies and
Within 6 weeks, optic disk atrophies and
becomes pale.
becomes pale.
Factors Associated with Perioperative
Ischemic Optic Neuropathy
��Systemic hypotension
Systemic hypotension
��Blood loss/anemia
Blood loss/anemia
��Increased intraocular pressure
Increased intraocular pressure
��Abnormal
Abnormal autoregulation
autoregulationof ON circulation
of ON circulation
��Anatomic variation of ON vasculature
Anatomic variation of ON vasculature
��Emboli
Emboli
��Use of
Use of vasopressors
vasopressors
��Presence of systemic disease
Presence of systemic disease
��Retrobulbar
Retrobulbarhemorrhage
hemorrhage
Factors Related to Ischemic Optic
Neuropathy
��Hypotension
Hypotension----
��Not present in all cases but cited as important.
Not present in all cases but cited as important.
��Can lead to decrease in perfusion pressure of
Can lead to decrease in perfusion pressure of
optic nerve (ON).
optic nerve (ON).
��Anterior ON at risk because of anatomic
Anterior ON at risk because of anatomic
variation or abnormal
variation or abnormal autoregulation
autoregulation..
��Posterior ON at risk because of limited blood
Posterior ON at risk because of limited blood
supply to area.
supply to area.
��““Safe
Safe””lower limits of blood pressure not known.
lower limits of blood pressure not known.
Factors Related to Ischemic Optic
Neuropathy
��Blood Loss / Anemia
Blood Loss / Anemia
��From case reports, considerable blood loss.
From case reports, considerable blood loss.
��Decreased hemoglobin levels
Decreased hemoglobin levels intraoperatively
intraoperatively..
��Presently, routine clinical practice based on
Presently, routine clinical practice based on
NIH Panel on Blood Transfusion is not to
NIH Panel on Blood Transfusion is not to
transfuse for
transfuse for Hgb
Hgb> 8
> 8 g/dL
g/dL..
��Are decreased
Are decreased Hgb
Hgblevels placing patients at
levels placing patients at
risk for ION?
risk for ION?
Factors Related to Ischemic Optic
Neuropathy
��Increased Intraocular Pressure
Increased Intraocular Pressure
��ION reported with massive fluid replacement in
ION reported with massive fluid replacement in
prone position.
prone position.
��Many cases report no pressure to orbits (head in pin
Many cases report no pressure to orbits (head in pin
holders).
holders).
��Massive fluid therapy with or without prone
Massive fluid therapy with or without prone
��Increased IOP
Increased IOP
��Accumulation of fluid in the optic nerve (ON).
Accumulation of fluid in the optic nerve (ON).
��Small vessels on
Small vessels on ON
ONcompressed, resulting in
compressed, resulting in
decreased arterial supply
decreased arterial supply
��Increased orbital venous pressure, venous stasis
Increased orbital venous pressure, venous stasis
Factors Related to Ischemic Optic
Neuropathy
��Autoregulation
Autoregulationand Anatomic Variation of
and Anatomic Variation of
the Optic Nerve
the Optic Nerve
��Anatomic variation may predispose to ION.
Anatomic variation may predispose to ION.
��Location of potential watershed zones in ON
Location of potential watershed zones in ON
circulation plus the presence of disturbed
circulation plus the presence of disturbed
autoregulation
autoregulationin healthy patients cannot be
in healthy patients cannot be
predicted at this time.
predicted at this time.
��20% of healthy patients with increased IOP
20% of healthy patients with increased IOP
have been found to have abnormal
have been found to have abnormal
autoregulation
autoregulation..
Factors Related to Ischemic Optic
Neuropathy
��Emboli
Emboli
��Most likely to occur during cardiac surgery.
Most likely to occur during cardiac surgery.
��Air embolism through patent foramen
Air embolism through patent foramen ovale
ovale
��Vasopressors
Vasopressors
��Anterior ION related to excessive secretion of
Anterior ION related to excessive secretion of
vasoconstrictors, lowering optic nerve perfusion.
vasoconstrictors, lowering optic nerve perfusion.
��Case reports of patients with ION after prolonged
Case reports of patients with ION after prolonged
use of epinephrine and
use of epinephrine and phenylephrine
phenylephrineduring
during
operative procedure.
operative procedure.
Factors Related to Ischemic Optic
Neuropathy
��Patients with Hypertension, DM, CAD, or
Patients with Hypertension, DM, CAD, or
Previous Stroke
Previous Stroke
��Not present in all patients
Not present in all patients
��Typically found in patients for cardiac surgery.
Typically found in patients for cardiac surgery.
��Theory that
Theory that perioperative
perioperativeION is related to
ION is related to
atherosclerosis
atherosclerosis ----ON vasculature responds
ON vasculature responds
abnormally to changes in perfusion pressure
abnormally to changes in perfusion pressure
(disturbed
(disturbed autoregulation
autoregulation).).
Factors Related to Ischemic Optic
Neuropathy
��Retrobulbar
RetrobulbarHemorrhage
Hemorrhage
��Direct surgical injury to ON
Direct surgical injury to ON
��Indirect damage by compression more common
Indirect damage by compression more common
��Paresis of eye muscles often seen
Paresis of eye muscles often seen
��Outcome poor, usually permanent blindness
Outcome poor, usually permanent blindness
Benumof2004
CSA Refresher Course San Diego
Ischemic Optic Neuropathy
��Prognosis and Treatment
Prognosis and Treatment
��No proven treatment
No proven treatment
��Diamox
Diamoxlowers IOP, may improve flow to
lowers IOP, may improve flow to
anterior ON and retina.
anterior ON and retina.
��Diuretics may decrease edema
Diuretics may decrease edema
��Corticosteroids may decrease ON swelling in
Corticosteroids may decrease ON swelling in
acute phase.
acute phase.
��Increasing systemic BP /
Increasing systemic BP / Hgb
Hgblevel
level
��Maintain head
Maintain head-- up position to decrease ocular
up position to decrease ocular
venous pressure.
venous pressure.
��Surgical ON decompression ineffective
Surgical ON decompression ineffective
Ischemic Optic Neuropathy:
Prevention
Prevention
��Status of patient
Status of patient ’’s ON circulation is unknown.
s ON circulation is unknown.
��Presently, no effective ON monitoring available.
Presently, no effective ON monitoring available.
��Maintain systemic blood pressure as close to
Maintain systemic blood pressure as close to
baseline as possible (BP > 75% of control).
baseline as possible (BP > 75% of control).
��If If vasopressors
vasopressorsare used to maintain BP, impact
are used to maintain BP, impact
on
on ON
ONvasculature not known.
vasculature not known.
��Consider
Consider Hgb
Hgboptimization vs. lowest acceptable
optimization vs. lowest acceptable
(( Hgb
Hgb> 9
> 9 g/dL
g/dL, , Hct
Hct> 27%).
> 27%).
��Maintain SaO2 > 95% (? low PEEP).
Maintain SaO2 > 95% (? low PEEP).
Ischemic Optic Neuropathy:
Prevention
Prevention
��CVP placement to monitor venous pressure.
CVP placement to monitor venous pressure.
��Minimize protracted periods of prone and
Minimize protracted periods of prone and
prone/
prone/Trendelenberg
Trendelenbergpositions.
positions.
��Proper positioning
Proper positioning
��Avoid abdominal compression.
Avoid abdominal compression.
��Assure adequate chest excursion.
Assure adequate chest excursion.
��Avoid external pressure to orbits.
Avoid external pressure to orbits.
��Discuss the risk of ION with surgeon.
Discuss the risk of ION with surgeon.
Informed Consent?
��Controversial
Controversial
��Despite potential devastating injury, only
Despite potential devastating injury, only
theories exist to the cause of ischemic optic
theories exist to the cause of ischemic optic
neuropathy.
neuropathy.
��Few clinicians include in informed consent.
Few clinicians include in informed consent.
��Consider including with:
Consider including with:
��Jehovah
Jehovah’’ s Witness patient
s Witness patient
��Case in which surgeon requests deliberate
Case in which surgeon requests deliberate
hypotension/
hypotension/ hemodilution
hemodilutionin prone position.
in prone position.
Practice Advisory:
Anesthesiology 2006; 104: 1319-28
Summary
��ION
ION --multifactorial
multifactorialcauses
causes
��Predisposing factors remain unknown.
Predisposing factors remain unknown.
��““Safe
Safe””limits for hypotension and hemoglobin
limits for hypotension and hemoglobin
levels have not been validated.
levels have not been validated.
��Have documentation of surgeon
Have documentation of surgeon’’ s demand for
s demand for
deliberate
deliberate hypotensive
hypotensiveprone procedures.
prone procedures.
��CRAO
CRAO --avoid compression of globe.
avoid compression of globe.
��All patients experiencing visual changes
All patients experiencing visual changes
need an
need an opthalmology
opthalmologyconsult.
consult.
��Statistics regarding your patient experiencing
Statistics regarding your patient experiencing
postoperative visual loss.
postoperative visual loss.