Issue 3, October 2000 - British Ophthalmic Anaesthesia Society

39 Pages·2001·0.37 MB·English

by  Steve Moore

Ophthalmic Anaesthesia News
The Official Newsletter of the British Ophthalmic Anaesthesia Society
Issue 3, October, 2000

BOAS Meeting Report, June 28-30th, 2000
Page - Contents
Dr Chandra Kumar
1. BOAS, Bristol meeting report
5. OAS Chicago report South Cleveland Hospital
7. Anaesthesia for strabismus Middlesbrough TS4 3BW
surgery

12. Preoperative evaluation of
This was my first visit to Bristol. I was excited to be there before the
cataract patients
BOAS meeting. My good friend, Dr Robert Hustead, accompanied me.
15. Learning to perform local
anaesthesia blocks for eye surgery Bob is an ex pilot and a very good navigator. His directions were superb
16. Sub-Tenon anaesthesia even all the way from Middlesbrough to Bristol. When we arrived in Bristol
simpler technique
City near the hotel, we could not find the hotel car park although we could
18. BOAS 2001 meeting dates
see the hotel. Bob was scheduled to conduct the workshop on anatomy.
and contact details
The time was approaching fast. Ultimately, we managed to park the car in
20. BOAS related news
21. Recent publications of interest the designated area. We went straight to the hotel reception and asked for
38. Members list the rooms, but they were not ready for occupation. We were eager to be
39. Middlesbrough course detail
dressed properly for the occasion, but we could not find an appropriate

place to change our clothes. Bob came up with a bright idea and suggested

why don(cid:146)t we get changed in the car park. We re-parked the car in a corner
BOAS Registered Office
Department of Anaesthesia and we managed to change our shirts and trousers. Our wives helped us in
South Cleveland Hospital getting changed by cordoning off the area! We finally made it to the hotel.
Middlesbrough TS4 3BW UK
We were then taken to the Bristol simulation centre.
Tel [phone]

Fax [phone]

Email: [email protected]

Website: www.boas.org

Ophthalmic Anaesthesia News

Editor: Dr Chandra Kumar
.
Associate Editors

Dr Alison Budd

Dr Jonathan Lord

The Society can(cid:146)t be responsible
Dr Robert Johnson, BOAS 2000 Meeting Organiser
for the statements or views of the
contributors. No part of this
Newsletter may be reproduced
without prior permission.
Articles of interest for future issue
or correspondence should be sent
by post, disk or email:
Dr Chandra Kumar
Secretary, BOAS
South Cleveland Hospital
Middlesbrough
TS4 3BW
[email protected]
[email protected] Drs Stephen Mather and Francis Forrest, Co-organiser

Ophthalmic Anaesthesia News, Issue 3, October 2000
Email: [email protected] Website http://www.boas.org
There were other workshops but the one for After the hectic travelling and attendance at the
anatomy was important to us. The anatomy workshop, I had to attend then BOAS Council
workshop was jointly conducted by Dr Gary meeting prior to the reception in the Bristol
Fanning, Prof. Jonathan Dutton and Dr Bob City Museum. The whole museum was open to
Hustead. Despite being jetlagged and having us to visit. Drinks, food, music and the exhibits
difficulty with the technology, Jonathan of Bristol Museum made our evening very
presented anatomical illustrations in enjoyable.
PowerPoint superbly. The meeting was blessed
with the presence of Dr Roy Hamilton and the The venue for the main meeting was the
discussion was very enjoyable. Watershed Conference Centre, which was
only a walking distance from the hotels and
The second part of the workshop involved City. The meeting started with a welcome
simulation. The simulation workshop was a speech by Dr Robert Johnson, President of
live Internet transmission from the simulation BOAS. 120 delegates attended the meeting.
centre to one of the lecture room in the hotel. The theme of the first session was Risk and
Some delegates were in the hot seat. I was ophthalmic anaesthesia. The topics included
supposed be in the hot seat but I managed to preoperative assessment, preparation,
escape this sentence. The technology worked guidelines and consent to treatment.
fine and the delegates enjoyed the scenario on
the anaphylactic reaction.

Dr Marc Feldman addressing the issues on
preoperative assessment and preparations
Prof Jonathan Dutton participating in the
Anatomy Workshop

Dr Monica Hardwick talking on the
progress of the Joint Colleges Guidelines
Dr Gary Fanning participating in the

Anatomy Workshop
Free paper session was chaired by Dr Chandra

Kumar and trainees presented the abstracts.
Ophthalmic Anaesthesia News, Issue 3, October 2000
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The afternoon session theme was again
anatomy for those who missed the workshop.

In the evening we were taken to Ashton Court
for the dinner. The sight of Ashton Court was
amazing. The food was good and so was the
wine. The entertainment included a band all the
way from Newcastle. The group entertained us
for 3 hours. The evening will be remembered
for a long time to come.

Next day the meeting theme was World
Drs H Knight, Z Sheikh and S Vadodaria
anaesthesia for ophthalmology. Speakers from
presenting free papers
several different continents were the highlights

of this session. Three notable speakers were Dr
Three topics included local for vitero-retinal
Emile Calenda, France, Dr Alexander Logis,
surgery, Local anaesthesia for cataract
Russia and Dr Uday Goraksha, India. While
surgery:York experience and an audit of
Emile presented in English, Dr Logis spoke in
haemorrhagic complications in warfarinised
Russian with Dr Andrei Varvinski of Cardiff
patients.
giving simultaneous translation.

Mr Ken Barber, Dr Z Sheikh, Dr Monica

Hardwick and Dr Marc Feldman sitting in Dr Emile Calenda, France
the audience

Our distinguished speaker, Dr Tony Rubin,
delivered a prestigious new lecture entitled
(cid:147)The Abbott(cid:146)s Lecture(cid:148). The title of his talk
was Safer Local Anaesthetic Drugs.

Dr Alexander Logis, Russia

Dr Tony Rubin presenting Abbott’s Lecture
Ophthalmic Anaesthesia News, Issue 3, October 2000 3
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We were pleased to have the generous support
of many pharmaceutical companies and would
hope to see more companies participating in
the future events.

Dr Andrei Varvinski translator for Dr Logis

Dr Robert Johnson, Dr Chris Dodds and Dr
Roy Hamilton during Case Discussion

Dr Uday Goraksha, India

Delegates attending BOAS Meeting in
Watershed Conference Centre, Bristol

On the whole the meeting was superbly
organised and well attended. Drs Robert
Mr Tim Dowd (Treasurer), Dr Robert Johnson, Stephen Mather and Francis Forrest
Johnson (President) and Dr Chandra should be congratulated for their efforts in
Kumar (Secretary) during the Annual organising such a successful and thought
General Meeting provoking meeting.

The last session included another superb
We all look forward to meeting again next year
presentation by Dr Gary Fanning. This session
in London.
ended with case discussions. Drs Robert

Johnson, Chris Dodds and Roy Hamilton

selected three interesting cases and the
delegates participated in the discussion.

Ophthalmic Anaesthesia News, Issue 3, October 2000 4
Email: [email protected] Website http://www.boas.org
OAS meeting report
Chicago, 15-17th September 2000
Dr Robert Johnson
President BOAS
Consultant Anaesthetist
Bristol Royal Infirmary, Bristol
Flying over the Great Lakes from Amsterdam without putting patients at risk or slowing
(for some reason BA likes all Bristolians to fly down the list. Equally important, trainees
KLM as they provide no convenient means of taught in the way suggested would be well
reaching Heathrow) the colours were simply appraised of their progress without fear or
magnificent (cid:150) vivid turquoise and ultramarine. embarrassment.
It conveyed some of the beauty and excitement
expressed by patients on first being unpadded
after cataract surgery.

The OAS meeting is held in Chicago each year
by popular demand of the members. I can
understand this as it is a clean, attractive and
vibrant city with great museums, symphony
halls, jazz and restaurants. No cows this year
though (see last year(cid:146)s report). As ever, the
kindness and hospitality shown to the English
delegates (just three this year) was superlative
and much appreciated.

Dr David Greaves and Dr Robert Johnson
The programme was varied and stimulating. I
enjoying dinner hosted by Dr Gary Fanning
will say at the outset that David Greaves(cid:146) talk

on training and Chandra Kumar(cid:146)s on the
If I change to sub-tenon(cid:146)s, I think a modified
Greenbaum sub-tenon(cid:146)s technique were
Greenbaum technique would be my starting
exceptionally well researched, illustrated and
point. Talks on alternative medicine were
delivered (cid:150) that was not just my view.
enjoyable but probably would not have
convinced many of us that the scientific basis is
always as clear as the undoubted benefit that
some patients in some situations gain. A
beautifully illustrated talk on retinal surgery
convinced me, not that I had any doubts, that
these surgeons are very skilful and are
developing amazing techniques to restore and
preserve vision. I had no idea that retinal
relocation for macular degeneration was a
possibility.

Topical anaesthesia was addressed in several
Dr Chandra Kumar presenting anaesthetists presentations and the message was reasonably
evaluation of Greenbaum’s sub-Tenon clear that total comfort is rare unless there is
technique supplementation with sub-tenon(cid:146)s, intracameral
Certainly David Greaves produced a reasoned or some sedation or analgesia. One
and clear rationale for teaching regional blocks
Ophthalmic Anaesthesia News, Issue 3, October 2000 5
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presentation left me feeling rather
uncomfortable. There were presentations on anaesthesia
techniques for (cid:145)ambulatory(cid:146) surgery (cid:150) there
was both evidence and anecdote in favour of
dexamethasone (4 mg to an adult) as an
antiemetic particularly in combination with
ondansetron. Also, a case was made for timing
the administration of these drugs for twenty
minutes before the end of surgery. Preoperative
(cid:145)testing(cid:146) for cataract surgery reported the
important multicentre study published in
NEJM earlier this year. There is simply no
advantage to patient safety in performing tests
(haematology, biochemistry, ECG or

radiology) unless it would be indicated for a
Dr Paul Honan addressing on alternative
particular patient by the history and
medicine
examination even if the patient were not to

receive surgery under local anaesthesia. It must
It suggested that a safe technique involving
be likely that the long awaited (cid:145)new(cid:146) Colleges(cid:146)
midazolam, methohexitone and alfentanil with
guidelines will support this view. There were
NO local anaesthesia provided good patient
other good presentations and workshops and,
comfort and safety. Somehow, I felt that some
of course, stimulating discussions both between
LA drops before the drapes were placed may
talks and at coffee breaks.
have been contributory. I am sure it is fine in

the hands of those who presented but might not
It must be said that the absence of Bob Hustead
find favour with many of us.
and Roy Hamilton on this occasion did modify

the nature of discussion and both were greatly
missed. A very good meeting. I would strongly
encourage our members to attend the next OAS
meeting in Chicago in early October next year.
We do receive a concessionary OAS members(cid:146)
registration rate and booking early prevents a
financial penalty (phrased by OAS as an early
booking discount!) However, If you can only
attend one ophthalmic meeting next year, make
it BOAS in London on 28th June 2001.

Dr Gary Fanning and Robert Johnson in the
audience
A paper on risk critically (really quite critically
when it discussed CEPOD) discussed the
difficulty in obtaining accurate data for risk of
LA or GA. Specialist societies might well
organise data collection to review the situation
(cid:150) but this would be collecting the data of those
who arguably have the greatest knowledge of
ophthalmic anaesthesia. Nevertheless, it would
be a start.
Ophthalmic Anaesthesia News, Issue 3, October 2000 6
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ANAESTHESIA FOR STRABISMUS SURGERY

Dr. Stephen J. Mather
Sir Humphry Davy Department of Anaesthesia, Bristol Royal Infirmary
Bristol
Introduction General considerations
Many anaesthetists providing anaesthesia for Most of the patients are children, undergoing
ophthalmic surgery have not studied day care surgery. There are certain
ophthalmology itself in much depth, and requirements for this:
compared with their knowledge of general ASA I or II patients, although others with
surgery, or gynaecology, for example, their stable chronic disease may be considered,
appreciation of the perspective of the surgeon such as those with:
is sometimes found wanting. Nowhere is this Stable congenital heart disease
more so than in strabismus surgery, where Leukaemia
frequently a generic (cid:147)keep still(cid:148) anaesthetic is Cystic fibrosis
given, without a great deal of thought as to
what could be done to improve the quality of Occasionally, well children with a murmur are
anaesthesia, and to minimise the side effects, picked up at the pre-operative visit. Surgery
which are not inconsiderable. need not usually be cancelled, but referral for
an echocardiogram as an outpatient should be
Problems for the anaesthetist made.
• Most of the patients are children, often
small. Patients with known congenital heart disease
• They are usually day-cases must be carefully assessed pre-operatively. If
• There is a requirement to meet specific necessary, an echo-cardiogram should be
surgical conditions performed. Antibiotic prophylaxis is
• Untreated, there is a high incidence of unnecessary for squint surgery.

postoperative nausea and vomiting (PONV)
• Prophylaxis against the oculocardiac reflex Patients with diabetes, asthma or epilepsy
should be well controlled. Recent respiratory
is required
infection may exacerbate asthma and

laryngospasm3 and elective operations such as
Surgical requirements
• The squint angle as measured under strabismus surgery should be postponed until
the patient is fully well. Intubation intensifies
general anaesthesia is unpredictable,
although formulae do exist to predict it1,2 the tendency to cough and breath holding. A
recent history of pertussis or measles should
• The ocular alignment is usually more
lead to a delay of at least 6 weeks from the
divergent under anaesthesia (without
acute episode as the repiratory tract remains
neuromuscular blockade) than in the awake
irritable throughout this period4
state
Strabismus surgery generally does not place
• Modern inhalational agents produce poor
much stress on insulin-dependent diabetics, but
muscle relaxation and a variable end-point
care must be given to fasting, fluid
of gaze depending upon the depth of
management and post-operative insulin
anaesthesia and extra-ocular muscle tone
requirements. This should not limit access for
• Complete neuromuscular blockade is
day surgery.
required to produce a reproducible end-

point.
Social and family factors
Most patients for strabismus surgery are day
cases. For children, one must rely upon the
Ophthalmic Anaesthesia News, Issue 3, October 2000 7
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parents to follow starvation guidelines and to Consensus is difficult to achieve, but the
arrange suitable transport. Sometimes transport modern view is that in infants and children
must be provided by the hospital. The distance over 1 year, and also in older children and
between hospital and home is important, but adults, 4h starvation for food and milk and 2h
arbitrarily defined. A common cut-off point is for clear fluid (water, black coffee or tea)
10 road miles or 20 minutes journey time. If seems safe. If necessary, children should be
returning home, carers and parents must have admitted in time to ensure that they do have a
access to a telephone in order to be able to call drink 2-3h before surgery. This is difficult for
the hospital for advice or reassurance. It is morning lists.
important to advise carers about driving style,
since abrupt turns and fast cornering may Since strabismus surgery, in untreated patients,
exacerbate PONV. results in a high incidence of nausea and
vomiting, many anaesthetists advocate that
Pre-operative preparation and fasting patients who have undergone overnight
regimens starvation should be given intravenous fluid.
Day patients need not be admitted more than There is some evidence that this reduces
two hours before surgery, provided they have nausea.
been pre-assessed. Adequate time must be
allowed, however, for the administration of Premedication
pre-operative analgesic premedication. Sedative premedication is almost always
Haemoglobin estimation is not necessary unnecessary unless the child has cerebral palsy
unless the patient is clinically anaemic or has a or a previous adverse experience of
haemoglobinopathy. Sickle status should be anaesthesia. Local anaesthetic cream should be
known. applied in 2 sites if an intravenous induction is
planned. Reassurance, and encouragement to
Psychological preparation of children and their the parent to accompany the child, and cuddle
parents is important in coping with a hospital the younger ones, is generally the best
admission5. Many hospitals address this approach.
question with a booklet or video, or a visit to
the ward. Paracetamol (acetaminophen) premedication
(30mg/kg orally 1h pre-op.) allows the use of
Fasting regimens are many and varied, but the minimal opioid during the operation.
evidence suggests that clear water may be Diclofenac or ibuprofen may also be given pre-
taken until close to the time of surgery. In operatively as adequate tissue levels will then
small children, hypoglycaemia must be be obtained at the time of surgery. Per-
avoided, but this is very unlikely to occur, even operative rectal non-steroidals, or IV ketorolac
in babies, with a fast of 4h. The effect of are often given, but it takes from 45 min
fasting on the emotional state of a child must (ketorolac) to more than 1h (rectal diclofenac)
be considered, but it is thirst, rather than to achieve an analgesic effect.
hunger, which is most distressing. This is also
true for older children and adults. Atropine should not be given orally at this time
Recommended fasting times vary from 2h6 to as it will cause distressing dry mouth.
4h7 in the literature. It has been advocated8 that Intramuscular injections should be avoided in
the administration of apple juice (3ml/kg) 2h children. Blocking of the oculocardiac reflex
pre-operatively results in a reduced gastric should be part of the anaesthetic sequence
volume, with less thirst and hunger. Milk must rather than premedication.
be regarded as a solid and may slow gastric
emptying. Breast milk may be better absorbed Anaesthetic technique
than cow(cid:146)s milk. Parental presence in the anaesthetic room is a
matter for the anaesthetist(cid:146)s discretion, as is a
Ophthalmic Anaesthesia News, Issue 3, October 2000 8
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preference for intravenous or inhalational protection against PONV. The oculocardiac
induction. Much will depend upon the age of reflex, producing bradyarrhythmias, is more
the patient and the anaesthetist(cid:146)s ability to prominent after propofol TIVA (with nitrous
secure an intravenous cannula in smaller oxide) compared to nitrous oxide-isoflurane
children. High quality assistance, of course, (50% vs 15%)10,11,12 The oculocardiac reflex
should always be available, but this is even can be abolished by conventional peribulbar
more important in paediatric anaesthesia. block or a single caruncular injection of local
Whichever agents are employed for induction anaesthetic (LA)13. Sinus arrest (lasting>10s)
and maintenance of anaesthesia, the paramount occurred in 15% of untreated patients in a
aim is to avoid PONV, which has a high study by Ruta et al14. Sinus arrest, rather than
incidence in strabismus surgery, up to 60% in profound bradycardia, is more common in
some series9. younger children.

Choice of induction agent The use of a caruncular injection of LA is not
For practical purposes, the choice of agent is widely practised in the UK but deserves more
between propofol and sevoflurane. attention. In the paper by Guerzider et al13 ,
Thiopentone and halothane are only rarely used none of 37 children undergoing strabismus
nowadays in the UK, although thiopentone is surgery with TIVA and caruncular LA
still widely used in Europe and the USA. manifested reflex bradycardia.
Thiopentone may cause nausea, even after a
single dose. In Bristol, the change from The use of LA avoids the need for prophylactic
thiopentone to propofol in the 1980s, while anticholinergics, which are usually given in
maintaining exactly the same volatile agent high doses, which produce unwanted
technique in every other respect, led to a fall in tachycardia. For prophylaxis, if LA is not used,
postoperative vomiting from 25% to 12%. glycopyrronium [glycopyrrolate](5
micrograms/kg IV) is preferred as it produces
Maintenance of anaesthesia less peak tachycardia and lasts longer than
The broad choice lies between total intravenous atropine. Onset of action is, however, rather
anaesthesia (TIVA) with propofol, and slow, and atropine (10 (cid:150) 20 micrograms/kg) is
maintenance with a volatile agent, with or preferred to treat established bradycardia. The
without nitrous oxide. The choice of volatile oculocardiac reflex can also be prevented by
can be further refined to sevoflurane or the topical application of local anaesthetic
isoflurane. Sevoflurane has little advantage solution to the muscle after opening the
over isoflurane for short procedures, and may conjunctiva14.
cause more post-operative nausea. Personal
experience suggests that added nitrous oxide
seems to make little difference to PONV in
children.
The lowest incidence of PONV in strabismus
surgery is provided by TIVA with propofol10,
even when supplemented by low-dose
fentanyl11 or sufentanil 12 or nitrous oxide12.
Children require significantly higher
maintenance doses of propofol (12 (cid:150) 15
mg/kg/h) than adults. Propofol infusion is not

recommended for children less than 3 years,
but single induction doses are widely used in In a study by Tramer et al, 15 the use of
small infants outside the neonatal period. propofol TIVA resulted in a greatly increased
A single induction dose of propofol, followed incidence of reflex bradycardia (40% compared
by volatile agent maintenance, confers no with isoflurane 14%), even after 20
Ophthalmic Anaesthesia News, Issue 3, October 2000 9
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micrograms/kg prophylactic atropine! agent could provide reasonable extraocular
Interestingly, the incidence of PONV in this muscle relaxation, adequate for surgery.
study was similar in both groups. No nitrous
oxide was used, and all children received
alfentanil. This seems at variance with most
other published work.
Many anaesthetists now routinely use the
laryngeal mask airway in ophthalmology as
there is less breath holding, laryngospasm or
bronchospasm on removal than with a tracheal
tube. Small children ( <1 y), however, are more
difficult to manage, especially when ventilated,
as the LMA often does not fit well , there are
large leaks, and the risk of displacement is
high. This is no longer the case when isoflurane or
sevoflurane are used for maintenance. The
Intra-operative analgesia measured angle of squint will be inaccurate as
Opioids seem to increase PONV more than the gaze tends to deviate from the straight
nitrous oxide in this group of patients, who are ahead position, unless anaesthesia is very deep.
mostly children in the published studies. This The use of neuromuscular blockade provides a
accords with clinical practice in many peoples(cid:146) reproducible end-point, when there is no tone
experience. A logical approach might be to use in the muscles, and the position of the eye is
little or no opioid and to provide analgesia by a dictated by the fixed length of the muscles.
combination of paracetamol, NSAIDs and
local anaesthetic block. If opioids are used, Any non-depolarising neuromuscular blocking
they should be short-acting e.g alfentanil or agent may be used, and can be chosen to suit
small doses of fentanyl. the expected duration of the operation.
Intraoperatively, nitrous oxide can be added for Atracurium, vecuronium and rocuronium are
the duration of the initial dissection and then all commonly used. Full neuromuscular
withdrawn. blockade must be maintained at least until a
forced duction test has been performed, or the
The use of 0.1% diclofenac eye drops (Voltarol degree of resection/recession has been decided.
OphthaR)) has been shown to produce much Some surgeons request continuing paralysis for
longer lasting analgesia than oxybuprocaine the whole of the surgery.
(benoxinate) when applied to the conjunctiva16. Using full neuromuscular blockade, a lighter
In addition, the oculocardiac reflex was not level of general anaesthesia can be used, which
observed in the 40 children in the study by reduces the doses of agents given, providing
Morton et al. We have modified their approach for a faster recovery. It is not clear whether this
and apply the drops directly to the muscle, actually reduces PONV in these patients.
under direct vision, before closure of the
conjunctiva. Topical ketorolac has also been Anti-emetics
used for this purpose. Many attempts have been made to reduce
PONV by the use of antiemetic drugs. No one
Neuromuscular blockade antiemetic is entirely efficacious. Ondansetron
Many anaesthetists still use spontaneous and granisetron17 appear to be useful in
ventilation with volatile agents when providing strabismus surgery, although evidence is
general anaesthesia for strabismus surgery. In conflicting. In the study by Tramer et al15,
past times, when halothane was almost ondansetron 5mg/m2 was given to children
universally used, deep anaesthesia with this aged 3 to 16 years who received thiopentone-
isoflurane without nitrous oxide. The
Ophthalmic Anaesthesia News, Issue 3, October 2000 10
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