Abstracts presented at the British Ophthalmic Anaesthesia

Society Meeting in Birmingham, on 28 June 2002

Ophthalmic pain following vitrectomy:an audit of current practice

R. Barnes, K. Prince and F. IdreesDepartment of Anaesthesia, Royal Berkshire Hospital, London Road,

Reading, UK

Current local practice for patients undergoing vitrectomy

involves general anaesthesia with or without topical

analgesics, with regular simple analgesics and opioid-based

analgesics as required postoperatively. No local anaesthetic

eye blocks are currently inserted. A literature search on

Medline revealed no trials comparing local anaesthetic eye

blocks with oral and topical analgesia. We reviewed local

practice to assess whether it might be beneficial to use local

anaesthetic blocks to improve analgesia after vitrectomy.

Methods

Patients undergoing vitrectomy were seen pre-operatively

and given a questionnaire enquiring about anxiety levels

and expectations of pain. The patients were followed up

postoperatively and further questionnaires enquired about

analgesia given intraoperatively; postoperative nausea and

vomiting; time to eating and drinking; and pain scores.

The patients were asked to take further questionnaires

home to assess pain relief on the second and third

postoperative days. Pain was assessed using verbal scoring.

Results

Over the one-month period a total of 15 patients were

recruited. Response rate was 80% (12/15). Pain was

found to be worst on day 1 and minimal by day 3. Five

out of 12 patients reported moderate to severe pain on

day 1. This was associated with nausea and vomiting in

four cases. Of these, three patients received opioid-based

analgesics such as codeine and tramadol. In the group

reporting no pain or mild discomfort (seven cases), no

patient received opioid analgesics. Patients who com-

plained of nausea and vomiting (four cases) had an average

time to eating and drinking of 3.56 h compared to 2.21 h

in the group without nausea and vomiting (eight cases).

There was a positive relationship between anxiety levels

pre-operatively and pain scores postoperatively (Pearson

correlation coefficient 0.86).

Discussion

Present standards of analgesia appear unsatisfactory. The

simple analgesics used are inadequate in a large proportion

of cases. Patients with higher pain scores are those who

are more anxious pre-operatively, for whom opioid

analgesics are prescribed and who complain of nausea and

vomiting with a longer period before normal oral intake is

resumed. This may have implications for certain patient

groups (e.g. diabetics). Introduction of local anaesthetic

eye blocks in addition to regular simple analgesics such as

paracetamol and NSAIDs might reduce pain scores over

the initial difficult 24 h. Use of opioid-based analgesics

should be avoided if possible, as these seem to increase the

incidence of postoperative nausea and vomiting.

Sub-Tenon’s anaesthesia for cataract surgeryusing a plastic cannula

Z. I. Sheikh and J. LuthmanDepartment of Anaesthesia, Kettering General Hospital, Rothwell

Road, Kettering, Northamptonshire NN16 8UZ, UK

Local anaesthesia for cataract surgery is widely used at the

Kettering General Hospital. Peribulbar block for local

anaesthesia described by Hamilton [1] is the most popular

technique. For the last two years there has been an

increase in the use of the sub-Tenon’s block for cataract

surgery using a single compartment technique described

by Stevens [2]. Kumar et al. [3] reported the use of a

plastic cannula to deliver local anaesthetic in the sub-

Tenon’s space to perform local block for cataract surgery.

This study was undertaken to evaluate the usefulness and

effectiveness of a plastic cannula to perform the sub-

Tenon’s block for cataract surgery.

Methods

After Local Research Ethics Committee approval and

patients� consent, we included all patients presenting for

Publication of these abstracts is on the understanding that they meet the rules for publication of abstracts presented at specialist society meetings, which

may be found in the general Instructions to Authors in the Jan issue of Anaesthesia or on the journal’s website (http://www.blackwellpublishing.com/

journals/ana/submiss.htm.).

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502 � 2003 Blackwell Publishing Ltd502 � 2003 Blackwell Publishing Ltd

cataract surgery who were deemed fit to receive local

anaesthesia for cataract extraction. Experienced ophthal-

mic nurses undertook the screening procedure, which

included a thorough medical history and assessment for

the patients� ability to lie still for at least 45 min. The

patients were randomised to receive the local anaesthetic

via a plastic cannula or the commercially available curved

metallic cannula. A questionnaire was completed for

every patient.

Results

During the three-month study period 82 patients had the

sub-Tenon’s block for cataract surgery. Metallic cannulae

were used in 26 (32%) patients and plastic cannulae in

56 (68%). Four to six millilitres of lidocaine 2% were used

in over 95% of patients. Eyelid akinesia was achieved in

51(63%) patients and globe akinesia in 72 (88%). Mild or

moderate pain was experienced by a small number of

patients during establishment of the block; however, no

patient suffered severe pain at the time of injection or

during the operation and 90% of the patients reported no

pain during the operation. There were no complications

recorded in the three-month follow-up.

Discussion

Sub-Tenon’s anaesthesia using a plastic cannula is an

effective and reliable method, and can be successfully

achieved with little training. Use of a plastic cannula to

establish the block is a much cheaper alternative to the

commercially available metallic cannula. Much larger

randomised studies are needed to compare the two

techniques more fully.

References

1 Hamilton RC. Techniques of orbital regional anaesthesia.

British Journal of Anaesthesia 1995; 75: 88–92.

2 Stevens JD. A new local anaesthesia technique for cataract

extraction by one quadrant sub-Tenon’s infiltration. British

Journal of Ophthalmology 1992; 76: 670–4.

3 Kumar CM. A simple method of sub-Tenon anaesthesia

delivery. Anaesthesia 2000; 55: 612–13.

Anticoagulation and intra-ocular surgeryunder local anaesthesia

J. Singh and K. BarberDepartment of Ophthalmology, Worcestershire Royal Hospital,

Worcester WR5 1DD, UK

The number of patients undergoing anticoagulation

therapy is increasing. Indications for anticoagulation

include atrial fibrillation, heart valve disease, pulmonary

embolus, deep vein thrombosis and transient ischaemic

attacks. Prophylactic measures are aimed at reducing

the risk of thrombosis. The main complication from

this therapy is haemorrhage. The Royal Colleges of

Ophthalmologists and Anaesthetists produced guidelines

on local anaesthesia for intraocular surgery in 2001 [1].

The recommendations are that … ‘in procedures invol-

ving sharp needles or sub-Tenon’s block, it is important

that the international normalised ratio (INR) is known.

The level should be within the recommended therapeutic

ratio, which is determined by the condition for which the

patient is being anticoagulated�. The therapeutic range for

oral anticoagulant control is that proposed by the British

Society for Haematology: atrial fibrillation (AF) INR 2.0

(2.0–3.0), heart valve disease INR 3.8 (3.0–4.5) and

pulmonary embolus (PE) or deep vein thrombosis (DVT)

INR 2.5 (2.0–3.0). The aims of this project were to

determine whether the unit was practising within these

guidelines, and to ascertain the rate of complications as a

direct result of anticoagulation.

Methods

A retrospective study was undertaken on patients under

the care of two consultant ophthalmic surgeons. The

notes of 50 patients receiving anticoagulation therapy

who underwent phakoemulsification between 1999 and

2002 were analysed. Data recorded included sex; age;

reason for anticoagulation therapy; drug and dosage;

pre-operative INR; length of time between INR

assessment and day of surgery; type of anaesthetic; pre-

peri- and postoperative (up to 4 weeks) complications;

and any changes made to anticoagulation therapy for the

surgery.

Results

Average age was 77 years. The most common indica-

tions for anticoagulation were AF (48%), heart valve

disease (28%), transient ischaemic attacks (14%) and

DVT (4%). All patients were on warfarin, the average

dose being 3 mg. Their INR was measured 3–14 days

pre-operatively. In 6% of the patients, pre-operative

INRs were reported above the therapeutic range, while

26% of patients had pre-operative INRs below the

therapeutic range. In 76% of patients, peribulbar anaes-

thetic was used and in the remainder, sub-Tenon’s;

58% of patients who had sub-Tenon’s anaesthesia

suffered pre-operative subconjunctival haemorrhage.

No peri-operative problems were reported. Only one

postoperative problem was reported, a spontaneous sub-

conjunctival haemorrhage.

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Discussion

The data revealed that complication rates were excep-

tionally low and complications minor in nature. On

reviewing compliance with the Royal Colleges� guide-

lines, however, a more interesting and unexpected feature

of the dataset was the fact that 32% of patients� pre-

operative INRs were outside the therapeutic range.

Although one patient had surgery postponed due to a

high INR, the remainder underwent surgery nevertheless

and without any complication. This study has raised

several issues including whether there is a lower limit of

INR below which local anaesthesia and intraocular

surgery would be contra-indicated; where the responsi-

bility lies for abnormal levels of anticoagulation; and who

should be informed with regard to further management of

these under-anticoagulated patients.

Reference

1 Royal College of Ophthalmologists and Royal College of

Anaesthetists. Local anaesthesia for intraocular surgery. London,

2001.

Anaesthesia for surgical decompressionof the orbit in severe thyroid orbitiopathy

L. Stannard, R.M. Slater and B. LeatherbarrowDepartment of Anaesthesia, Central Manchester and Manchester

Children’s University Hospitals, Manchester, UK

Anaesthesia for surgical decompression of the orbit in

severe thyroid orbitiopathy has rarely been reported in

the literature. This review highlights patients�, anaesthetic

and surgical factors of relevance.

Methods

We carried out a retrospective analysis over a 3-year

period of the records of 35 patients who had undergone

surgical orbital decompression via a trans-lid approach

under general anaesthesia.

Results

A total of 58 decompressions were performed on 35

subjects (26 women, 9 men; age range 34–76 years).

Twenty-four patients had bilateral decompressions (seven

had both sides performed simultaneously, whereas 17 had

each side performed separately at least one month apart).

Eleven required unilateral decompression only. Surgery

was repeated on six occasions in four of the 35 patients.

The main indications for surgery were compressive optic

neuropathy (n ¼ 17) and disfiguring proptosis (n ¼ 19).

Fourteen patients had more than one indication. Of the

35 patients, 33 had a history of hyperthyroidism whereas

the remaining two were clinically and biochemically

euthyroid. In all cases, T4/TSH levels were normal pre-

operatively. Two thirds were smokers (the majority

smoking 10–20 cigarettes/day). Pre-operative morbidities

were as follows: diabetes mellitus (n ¼ 5), chronic airflow

limitation (n ¼ 4), asthma (n ¼ 4), hypertension (n ¼ 4),

obesity (n ¼ 3), ischaemic heart disease (n ¼ 2), arrhyth-

mias (n ¼ 2) and CVA (n ¼ 1). Five had 2–3 com-

orbidities. Fifty-one percent were taking prednisolone

pre-operatively (dose range 10–80 mg).

Average duration of anaesthesia was 119 min for

unilateral surgery and 184 min for bilateral surgery. In

88% of cases, balanced anaesthesia involved a volatile

agent (isoflurane > sevoflurane > enflurane), O2 /N2 O

mixture and either remifentanil or fentanyl ± morphine,

whereas in the remaining 12% of cases remifentanil,

target-controlled infusion of propofol and O2/air mix-

tures were used. Normotensive anaesthesia was used

throughout. Intravenous acetazolamide was given on

induction to reduce intraocular pressure. Subcutaneous

local anaesthetic (bupivacaine with epinephrine) was

infiltrated under the eyelid before starting surgery.

Ketorolac and pethidine were given as adjuncts in 29%

and < 1% of cases respectively. In 26% of cases, anticho-

linergic therapy was required for bradycardia resulting

from orbital traction.

Postoperatively, nausea and/or vomiting was absent in

93% of cases, 57% of whom had not had antiemetic

therapy intraoperatively. Postoperative pain scores of zero

were recorded in 88% of cases, with the use of simple

analgesics (paracetamol/codeine) or no analgesics recor-

ded in 43% and 36%, respectively (for the entire hospital

stay). Discharge home was on the first postoperative day

in 76% of cases.

Significant peri-operative complications were as fol-

lows: one patient suffered a CVA two days postopera-

tively and a CSF leak developed intra-operatively in

another case (this resolved within 24 h and according to

protocol a lumbar drain was inserted). Infraorbital anaes-

thesia was experienced in five cases (9%) (with complete

resolution of symptoms after several months) and diplopia

developed (15%) or worsened (22%) overall in 37% of

cases.

Discussion

In our experience, anaesthesia for surgical decompression

of the orbit is generally safe, has a low incidence of

postoperative pain and nausea and vomiting and requires

only a short hospital stay. However, one must be aware of

the need to provide anaesthesia of long duration, and of

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504 � 2003 Blackwell Publishing Ltd

the high incidence of pre-operative morbidities, smoking

and high-dose steroid therapy.

Survey of the need for intravenous accessin ocular anaesthesia

W. Thomas and M. HardwickDepartment of Anaesthesia, Worcester Royal Hospital, Worcester,

WR5 1DD, UK

We aimed to measure the current practice of intravenous

cannulation and incidence of its use during ocular

anaesthesia [1].

Methods

A prospective survey was conducted in Worcester Royal

Hospital between August 2001 and April 2002. Adult

patients who underwent cataract/trabaculectomy under

local anaesthesia during this 9-month period were

included in the study.

Results

A total of 1203 patients were included in the study. All

cases during this period were done under local anaesthe-

sia. Among the local anaesthetic techniques, peribulbar

blocks were used in 84.5% and sub-Tenon’s blocks in

15.5%. No retrobulbar blocks were performed. Intraven-

ous access was established in 19.6% of cases; the use rate of

cannulas was 10% and the probability of using an

intravenous cannula for sedation or resuscitation was 2%

(Figure 1). Twenty-one patients (1.8%) required mida-

zolam for sedation. Adverse events were rare and only

three patients had bradycardia that required atropine.

Discussion

Only 19.6% of patients had intravenous access compared

to the national average of 60% [2, 3], and in only 10% of

patients was it actually needed. The recommendation for

the need for intravenous access in ocular anaesthesia is

thought by some to be overcautious. We suggest that

intravenous access should be considered in selected

patients who are at high risk of complications.

References

1 Royal College of Ophthalmologists and Royal College of

Anaesthetists. Local anaesthesia for intraocular surgery. London,

2001.

2 Eke T, Thompson J. The National Survey of Local

Anaesthesia for Ocular Surgery. I: survey methodology and

current practice. Eye 1999; 13: 189–95.

3 Eke T, Thompson J. The National Survey of Local

Anaesthesia for Ocular Surgery. II: safety profile of local

anaesthesia techniques. Eye 1999; 13: 196–204.

Aug

. '01

Sep

t. '0

1

Oct

. '01

Nov

. '01

Dec

. '01

Jan.

'02

Feb

. '02

Mar

. '02

Apr

il '0

2

Total patients

Can. Inserted

Can. Used

200

50

100

150

Figure 1 Use of intravenous access for ocular surgery by month.

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