Update on anaesthesia for paediatric ophthalmic surgery

Update on anaesthesia for paediatric ophthalmic surgerydoi: 10.1016/j.bjae.2020.09.002
Update on anaesthesia for paediatric ophthalmic
surgery
H. Lewis1,* and I. James1,2
1Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK and 2Institute of Child
Health, University College London, London, UK
*Corresponding author: [email protected]
dren are common.
creases in intraocular pressure, particularly in
glaucoma surgery and traumatic eye injuries.
Ophthalmic surgery can elicit the oculocardiac
reflex and is associated with a high incidence of
postoperative nausea and vomiting.
premature infants that require ophthalmic
Learning objectives By reading this article you should be able to
Discuss the anaesthetic considerations for com-
mon and more specialist ophthalmic conditions
requiring surgery in childhood.
them.
management of the child presenting for emer-
gency ophthalmic surgery.
Most paediatric ophthalmic surgery occurs in children of
ASA 1 or 2 under general anaesthesia. Surgery takes place in
children of all ages from neonates to teenagers, and peri-
operative anxiety can be common because children may
need to return for multiple procedures. Premedication and
inhalation or intravenous induction of anaesthesia is a
matter of the patient’s and the anaesthetist’s preference.
Hannah Lewis FRCA is a specialty registrar in anaesthesia at Great
Ormond Street Hospital for Children. She is co-chair of the national
Paediatric Anaesthesia Trainee Research Network (PATRN). Her
main interests are in quality improvement and management of
anxiety in children.
Ian James FRCA is a consultant anaesthetist at Great Ormond Street
Hospital for Children and honorary associate professor at the UCL
Great Ormond Street Institute of Child Health. He has specialist in-
terests in paediatric cardiac surgery and interventional cardiology.
Accepted: 2 September 2020
Crown Copyright © 2020 Published by Elsevier Ltd on behalf of British Journal o
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Most procedures can be carried out with a spontaneous
breathing inhalation technique and a supraglottic airway
device (SAD), but the anaesthetist needs to be mindful of
the fact that during some of the more complex procedures
there will be limited access to the head. For some proced-
ures the surgeon may require a completely still eye and
neuromuscular blockade will be needed. A remifentanil
infusion to provide intraoperative analgesia may avoid the
adverse postoperative effects of longer-acting opioids. This
can be combined with a volatile anaesthetic or a propofol
target-controlled infusion. Simple postoperative analgesia
with paracetamol, NSAIDs, and topical local anaesthetic is
usually adequate. Intraocular surgery requires an anaes-
thetic technique that does not cause an increase in intra-
ocular pressure (IOP); a smooth induction and emergence to
avoid coughing is important. The anaesthetist should be
vigilant for the oculocardiac reflex (OCR) most commonly
elicited in strabismus surgery. Postoperative nausea and
vomiting (PONV) is common after ophthalmic surgery.1e3
f Anaesthesia. All rights reserved.
Underlying diagnosis Ophthalmic conditions Anaesthetic issues
Craniosynostosis (Apert/Pfeiffer/Crouzon syndromes)
Craniofacial abnormalities (Treacher Collins/Goldenhar syndromes)
Cataracts/strabismus/glaucoma Difficult airway intubation difficult because of micrognathia and facial asymmetry
Mucopolysaccharidoses (Hunter’s/Hurler’s syndromes)
Cataracts/retinitis pigmentosa Difficult airway especially intubation Cardiac lesions cardiomyopathy
Chromosomal (Trisomy 21/Edward’s syndrome)
Cataracts/strabismus/glaucoma Difficult airway Difficult facemask ventilation, intubation, or both Cardiac lesions AVSD, tetralogy of Fallot Cervical instability
Neurocutaneous syndromes (Sturge Weber/Neurofibromatosis/Von HippeleLindau syndromes)
Retinal vascular disorders, glaucoma Seizures Cardiac lesions
Marfan’s syndrome Lens dislocation Cardiac lesions aortic root dilation, aortic valve regurgitation, mitral valve prolapse
Homocystinuria Lens dislocation Glucose control Thromboembolic events
Stickler’s syndrome (shares features of Pierre Robin)
Early retinal detachment and glaucoma Difficult airway Difficult facemask ventilation, intubation, or both
HallermaneStrieff syndrome Congenital cataract Difficult airway Difficult facemask ventilation, intubation, or both Neonatal anaesthesia (see below)
Neonates (including premature and ex-premature)
Congenital cataract ROP and retinal detachment
Neonatal anaesthesia Glucose control, temperature management, postoperative apnoea Bronchopulmonary dysplasia
Update on anaesthesia for paediatric ophthalmic surgery
Associated conditions
associated with cardiac lesions (Table 1).1,2
Oculocardiac reflex
Ophthalmic surgery can evoke a strong OCR resulting in a
profound bradycardia. Very rarely this may result in sinus
arrest. This is caused by pressure on the globe or traction of
the extraocular muscles and is mediated through trigeminal
afferent and vagal efferent pathways. It is more common in
children because of their higher vagal tone. This reflex is well
recognised as a complication of strabismus surgery but may
also occur during enucleation, vitreoretinal surgery and
orbital surgery. The surgeon should be asked to release trac-
tion on the eye muscles or pressure on the globe in the first
instance. A pre-filled syringe of atropine 20 mg kg1 or
glycopyrrolate 10 mg kg1 should be readily available and
administered if the bradycardia does not promptly recover.2
Postoperative nausea and vomiting
Ophthalmic surgery is emetogenic, and the risk of PONV in-
creases above the age of 3. Strabismus surgery is particularly
high risk. The Association of Paediatric Anaesthetists of Great
Britain and Ireland (APAGBI) updated its guidance on pre-
vention of PONV in 2016.4 Recommendations include dual
therapy in the operating theatre with ondansetron and
dexamethasone; and rescue therapy with a different agent,
such as droperidol, in the postoperative recovery room.
Dexamethasone is effective at preventing late (>6 h) PONV,
but is contraindicated in patients with a haematological ma-
lignancy as it can cause tumour lysis syndrome. Droperidol is
contraindicated in patients known to have a long QT interval.
Cyclizine is no longer recommended.4
BJA Education - Volume 21, Number 1, 2021 33
Table 2 Systemic effects of ophthalmic drops10
Eye drop Use Systemic effects
Beta blockers Timolol maleate (non- cardioselective) Betaxolol hydrochloride (cardioselective)
Reduce IOP e
Bradycardia, arrhythmia, Bronchospasm in susceptible asthmatics
Prostaglandin analogues Latanoprost (not commonly used in paediatrics e less responsive)
Reduce IOP e
Bronchospasm in susceptible asthmatics Increase pigmentation iris/ eyelashes/eyelids
Carbonic anhydrase inhibitors Acetazolamide (topical or oral) Brinzolamide (topical)
Reduce IOP e
glaucoma Reduce aqueous humour production.
Mainly oral preparation Promote renal loss of electrolytes and water Mild hyperchloraemic metabolic acidosis Nausea
NSAIDs Diclofenac sodium
Pupil dilation Tachycardia Hypertension
Pupil dilation Dry mucous membranes, tachycardia, vomiting
Local anaesthetic agents Oxybuprocaine 0.4%, proxymetacaine 0.5%, lidocaine 3.5%, tetracaine 0.5%
Analgesia and anaesthesia Cornea and conjunctiva only. Not intraocular structures Does not provide akinesia of the globe
Local anaesthetic toxicity Mainly premature neonates
Table 3 Effects of anaesthetic agents on IOP1,2
Anaesthetic drug Effect on IOP
Induction agents All lower IOP except ketamine
Ketamine Increase in IOP especially at doses above 5 mg kg1
Non-depolarising neuromuscular blocking drugs
Increase IOP up to 8mmHg for around 10 min
Volatile agents Lower IOP Nitrous oxide Minimal effect
Contraindicated in the presence of intraocular gas
Opioids Minimal effect Atropine No effect Ondansetron No effect
Update on anaesthesia for paediatric ophthalmic surgery
Analgesia and regional ophthalmic blocks
Most ophthalmic surgery is not overly painful, and simple
analgesia including paracetamol, NSAIDs and topical anaes-
thesia is usually sufficient. Vitreoretinal surgery, evisceration
of the orbital contents, open dacryocystorhinostomy (DCR),
and cryotherapy can be very painful and generally require
supplemental opioids. Strabismus surgery can also be more
painful than generally recognised.
adults including akinesis of the globe providing a still oper-
ating field, and a beneficial reduction in the OCR.5 The
improved perioperative analgesia minimises the need for an
opioid with a reduction in PONV.
There are three main types of blocks:
34 BJA Education - Volume 21, Number 1, 2021
Intraconal (retrobulbar)
Extraconal (peribulbar)
children because of safety concerns, although they have their
proponents; there are reports of their safe and effective use in
vitreoretinal surgery and for laser treatment in infants.6e8 A
sub-Tenon’s block is considered the safest in children with a
lower risk of complications of globe perforation, retrobulbar
haemorrhage, or inadvertent increases in IOP.6
The sub-Tenon’s technique is similar to that in adults,
allowing for differences in paediatric anatomy.6 The paediatric
globe is relatively large compared with the orbit, taking up
>50% of the space as opposed to 22% in adults. This leaves a
much smaller extraocular volume for the injection of local
anaesthetic and a higher risk of increasing IOP. The inferonasal
quadrant is typically used for insertion of the sub-Tenon’s
block. This is usually away from the operating site, avoiding
the insertion of oblique muscles. A blunt 19G or 21G 25 mm
needle is used to inject the local anaesthetic into the posterior
sub-Tenon’s space, blocking the short and long ciliary nerves.
This is most easily performed perioperatively by the surgeon.
Less than 5 ml of local anaesthetic should be used to avoid
increases in IOP. Lidocaine 1% or 2% or bupivacaine 0.5% are
common preparations used. A relative contraindication is a
scleral buckle as the block may not work as effectively and the
sclera can be adherent making access difficult.5,6
Certain ocular conditions including retinoblastoma (risk of
extraocular tumour seeding), trauma with an ‘open globe’,
and glaucoma (risk of detrimental increase of IOP) may not be
appropriate for ophthalmic blocks, especially intraconal
blocks.6
surgery also works well.
Children may be receiving ophthalmic drops before surgery.
These are also used frequently in the perioperative period to
provide local anaesthesia and to dilate the pupil for exami-
nation. Although not usually significant, systemic adverse
effects of the drops can be encountered under anaesthesia,
Update on anaesthesia for paediatric ophthalmic surgery
and it is important to be aware of them (Table 2).9 In partic-
ular, giving phenylephrine during surgery can lead to brief but
alarming tachycardia and hypertension.
The surgical and anaesthetic management of common
ophthalmic conditions in children has not changed dramati-
cally in recent years. These conditions are nevertheless
included briefly for completeness.
General anaesthesia may be necessary for examination of the
eyes in the uncooperative child. This may be because of the
child’s age, developmental delay, or extreme anxiety. Chil-
drenmay requiremultiple anaesthetics and awell-considered
induction of anaesthesia with management of anxiety is
important. The airway can be managed with a facemask or an
SAD althoughmeasurement of IOP should ideally occur before
airway manipulation to avoid artificially high readings.1,2
Normal IOP is 10e20 mmHg and exists as a balance be-
tween aqueous humour production and drainage. Anaes-
thesia for IOP measurement requires an understanding of the
effects of anaesthetic drugs on IOP, as most induction agents
reduce IOP (Table 3).
ophthalmologist ready to measure the IOP in the anaesthetic
room as soon as the child is asleep and the eyes are central.
Care must be taken not to apply external pressure to the eyes
with the facemask.
An alternative method, if venous access permits, is keta-
mine 1e2 mg kg1 intravenously. An antisialagogue may
offset the adverse effect of hypersalivation. The risk of a small
increase in IOP with ketamine giving an artificially high
reading avoids the danger of an artificially low reading with
other induction agents and a missed diagnosis of glaucoma.
Children may return regularly for repeat measurements of
IOP under anaesthesia, and it is preferable that the anaes-
thetic technique is consistent.1,2
of aqueous humour. Untreated high IOP can cause ischaemia
of the optic nerve resulting in blindness. Most cases are
congenital and result from failure of development of the
trabecular drainage network. The cornea is cloudy and
photophobia is common. These children will often be
receiving ophthalmic drops (most commonly timolol maleate)
to lower IOP, but these rarely work without surgery.10,11
Surgical techniques to improve drainage include goniot-
omy, trabeculectomy or trabeculotomy. A spontaneous
breathing technique is commonly used, although the use of a
neuromuscular blocking drug creates a quiescent eye and
ideal operating conditions.10,11 The use of a remifentanil
infusion can provide intraoperative analgesia and reduce the
need for neuromuscular blockade.3 Implantation of a glau-
coma drainage device can be used in cases when initial angle
surgery has failed. Cyclodestruction using laser or cryo-
therapy to ablate the ciliary body is another option.
Cataracts
Cataracts in children are common and if untreated can lead to
blindness. They can be inherited (autosomal dominant), part
of syndromes, or acquired after trauma or infection. Neonates
with congenital cataracts will require surgery in the newborn
period to preserve sight. Surgical management involves len-
sectomy and in most cases artificial lens implantation.12
Anaesthesia should provide a motionless eye and aim for
smooth emergence.
Strabismus surgery
cles may be tightened, lengthened, transposed, or shortened
to correct the defect.
Strabismus surgery has the highest incidence of exhibiting
the OCR and PONV. A sub-Tenon’s block at the beginning of
surgery can prevent the reflex and reduce PONV by blocking
the afferent limb. The combination of dexamethasone and
ondansetron has been shown to reduce the incidence of
PONV,13 and there may be a role for TIVA in this regard.
Strabismus surgery can be painful, and the judicious periop-
erative use of morphine rather than the shorter acting fenta-
nyl or remifentanil has been shown to reduce this without
increasing PONV.14 If not performed at the start, the surgeon
should perform a sub-Tenon’s block at the end of surgery.
Postoperative analgesia should include a combination of
paracetamol and NSAIDs, both of which should be given i.v.
during surgery, with topical local anaesthetic eye drops such
as tetracaine 0.5% or oxybuprocaine 0.4%.1,2,6
As ocular myopathies have been rarely associated with
malignant hyperthermia, suxamethonium is avoided and
temperature monitoring should be utilised.2
Blocked nasolacrimal ducts
general anaesthesia. In simple cases this is usually a short
procedurewith thepatient breathing spontaneouslywithaSAD.
The anaesthetist needs to be aware that saline or fluorescein
may be instilled into the duct and appear in the nasopharynx. A
suction catheter canbeplaced in thenose or pharynx to aspirate
the fluorescein to confirm duct patency. Sometimes it is
necessary to insert a silicone catheter into the duct.
More complex cases may require fracturing of the inferior
turbinate to open up the passage, or DCR to create a new
passage into the nasal cavity. This can be painful and short-
acting opioidsmay be needed. Bleeding from the nasalmucosa
can be ameliorated with topical vasoconstrictors such as
xylometazoline (otrivine) or lidocaine with phenylephrine
(cophenylcaine). Throat packs are used to protect the airway
from aspiration. At the end of the procedure, the airway
should be suctioned under direct vision to remove any clots or
debris.2
Traumatic eye injuries
Injuries to the eye are common in children. They can occur in
isolation or associated with polytrauma. In patients with
polytrauma, the management of life-threatening injuries
takes priority.
Update on anaesthesia for paediatric ophthalmic surgery
Eye injuries can be extraocular (muscles and other soft
tissues surrounding the eye), orbital (bony eye socket) or
ocular (the globe itself). Ocular injuries can be classified as
‘open’ or ‘closed’ globe. ‘Open’ globe injuries are where the
trauma has breached the full thickness of the sclera, the
cornea, or both.15
reducing eye movement and trigger the OCR. This requires
emergency surgery to free the muscles.16
‘Open’ globe injuries require urgent surgical repair to pre-
vent secondary injury from extrusion of ocular contents,
endophthalmitis and vision loss. This should be carried out
within 12e24 h of injury. Time to ensure a fasting status >6 h
may not be possible.15
An anaesthetic technique to avoid an increase in IOP and
loss of ocular contents in the unfasted patient creates chal-
lenges. A rapid-sequence induction (RSI) using sux-
amethonium, is classically advocated to reduce the risk of
pulmonary aspiration. There is controversy over the use of
suxamethonium because it causes a transient increase in IOP
and this increases the risk of extrusion of ocular contents in
‘open’ eye injuries. Rocuronium is a rapid-acting non-depo-
larising neuromuscular blocking drug suitable for use during
RSI; its effects can be reversed rapidly with sugammadex.
Although evidence suggests that the risk with sux-
amethonium ismore of a theoretical concern that is not borne
out in clinical practice, using rocuronium without an accom-
panying increased IOP makes it a sensible choice.1 Ketamine
increases IOP and is avoided, unless haemodynamic insta-
bility is a particular concern.17,18
Controlled ventilation to maintain normocapnia
(4.5e5.0 kPa) and a smooth emergence minimises further in-
creases in IOP. It is important not to cause additional external
pressure on the injured eye from the anaesthetic facemask.
A small proportion of children will tolerate removal of a
foreign body awake under local anaesthesia. Proxymetacaine
is the local anaesthetic of choice as it causes less stinging and
is better tolerated.
Vitreoretinal surgery: retinal detachment
Retinal detachment is when one or more tears form in the
retina. This allows vitreous humour to leak through and lift
the retina away from the underlying epithelium. This can be
sight threatening. Trauma is the most common cause. Pre-
disposing ocular and systemic conditions include retinopathy
of prematurity (ROP), retinoblastoma, Stickler syndrome
(syndromic myopia), Coats disease and CHARGE (Coloboma,
Heart defects, Atresia choanae, Growth retardation, Genital
abnormalities and Ear abnormalities) syndrome.19
Cryotherapy or laser can be used to repair smaller retinal
tears and to ablate the abnormal vessels in Coats disease. For
larger detachments vitrectomy, with the injection of silicone
oil or an intraocular gas such as hexafluoroethane (C2F6) into
the posterior chamber to hold the retina in place, may be
necessary. A scleral buckle, compressing the sclera on to the
retina, is another option. These surgical options will require a
still operating field and can be painful, and opioid analgesia is
indicated. A sub-Tenon’s block performed by the surgeon at
the start of the procedure will provide perioperative analgesia,
reduce the OCR, and minimise opioid requirements.6
The sealed tear takes around 10 days to become estab-
lished. If a gas bubble has been used, it is important that
nitrous oxide is not used for the following 12 weeks as this will
36 BJA Education - Volume 21, Number 1, 2021
cause dangerous expansion of the intraocular gas bubble. A
warning for any future anaesthetics in this time should be
provided to the patient.1
Corneal grafts
more common. Surgery is performed early to reduce the risk
of amblyopia, particularly with bilateral congenital opacities.
Corneal grafting traditionally involves a full-thickness pene-
trating keratoplasty, but there is increasing interest in the less
extensive partial thickness anterior lamellar keratoplasty.
Anaesthesia must facilitate a still eye for the duration of
the procedure as the surgical incision across the cornea is
large, risking extrusion of intraocular contents should there
be sudden increases in IOP. Neuromuscular block and
controlled ventilation is recommended. If tracheal intubation
has been performed, extubation under deep anaesthesia re-
duces the risk of coughing. Using a SAD can work well and
avoids the risk of increased IOP at extubation. A sub-Tenon’s
block ensures akinesis, provides analgesia and reduces the
incidence of PONV. This is contraindicated in ophthalmic in-
fections and may be less effective if the cornea is scarred.20
Retinoblastoma
cells. It is the most common intraocular malignancy in
childhood and represents 1% of all tumours in infancy. The
most common sign is leukocoria where the pupil reflects light
abnormally as a white reflex.
Children require multiple general anaesthetics for exami-
nation under anaesthesia (EUA), to deliver treatment and
assess response. EUA can be as frequent as every 4e8 weeks
until the child is 3 yrs old. Patients can be anxious and pre-
medication should be considered. The primary aim of treat-
ment is cure with secondary sight-saving benefits.
Treatment depends on the stage of the disease. For small
tumours, local therapies requiring general anaesthesia
include cryotherapy, laser photocoagulation, or plaque irra-
diation. For larger tumours systemic, intravitreal or intra-
arterial chemotherapy (IAC) is needed. Enucleation may be
necessary for advanced unilateral disease.21
Intra-arterial chemotherapy is a new treatment modality
for relapsed tumours. Melphalan is injected directly into the
ophthalmic artery. Intra-arterial chemotherapy is performed
in specialist centres with interventional radiology under
general anaesthesia, which carries the additional challenges
of remote site anaesthesia. Heparin 75 i.u. kg1 is given to
avoid thrombosis of the ophthalmic artery. Monitoring de-
vices and i.v. access should be positioned on the upper limbs
away from the operating field. Anaesthesia with neuromus-
cular block, tracheal intubation, and artificial ventilation is
needed. Controlled ventilation is important as the procedure
requires frequent ‘ventilator off’ and…