Page 148 - BSAVA Guide to Pain Management in Small Animal Practice

7 | Ophthalmic pain

VetBooks.ir Eyelid pain Deep ocular pain

Intraocular diseases such as uveitis and
Intraoperative pain management for eyelid
surgery can be particularly challenging and glaucoma often result in a marked pain
several analgesic options should be available response due to an increase in intraocular
to deal with treatment failure. Both systemic pressure. opical local anaesthesia is minimally
analgesia and topical local anaesthesia are e ective in these cases and therefore analgesia
useful in these cases. Local anaesthetic should be provided with opioids, ad unct
techni ues will be discussed later in this analgesics and, where appropriate, NSAI s.
chapter. Alongside opioid, topical local
anaesthesia and NSAI analgesia, ad unct
therapy with ketamine as a continuous Enucleation
infusion may be useful to provide intra
operative analgesia. Analgesia for enucleation should be achieved
with a multimodal approach utili ing opioid
analgesia and, where appropriate, NSAI s,
Corneal pain alongside local anaesthesia. Retrobulbar or
peribulbar anaesthesia can be administered
he cornea contains a high density of prior to surgical incision or, when not possible, a
nociceptors and a marked response is often splash block may be performed following globe
noted with conditions such as corneal removal. Local anaesthetic soaked gelatin
ulceration, along with any surgical intervention, sponge material Ploog et al., 14 may also be
due to exposure of nociceptors. Analgesia used to aid haemostasis and provide
should be provided using a multimodal postoperative analgesia. here a preoperative
approach, with a combination of systemic and local anaesthetic techni ue is not possible,
local analgesics. opical local anaesthesia alternative systemic intraoperative analgesia
provides excellent, rapid onset analgesia and should be provided.
will facilitate further clinical examination.
etracaine has a more rapid onset, but shorter
duration, than proxymetacaine and results in Local anaesthetic
less con unctival irritation on application.
etracaine followed by proxymetacaine may techniques
be used in the conscious patient. Repeated here possible, a local anaesthetic techni ue
application of single drops of drug solution should be incorporated into an analgesia plan.
onclin et al., 11 has been shown to Calculation of a maximum dose of local
provide improved analgesia of longer duration anaesthetic should be performed, and
in horses compared with that provided by aspiration is mandatory prior to in ection.
ooding the cornea. ood corneal lubrication
is essential and the contralateral cornea should Retrobulbar nerve block
also be treated. Systemic analgesia may be
provided with the use of opioids, such as Retrobulbar nerve block RBA is an e ective
methadone or buprenorphine, which provide techni ue to provide intra and postoperative
excellent to good analgesia, respectively. It has analgesia for enucleation and exenteration. he
been suggested that the cornea has opioid inferior temporal palpebral techni ue Accola
receptors within its structure, although et al., 6 has been documented to be a
evidence of the e ectiveness of topical reliable method in the dog. A retrobulbar
opioids is inconsistent homson et al., 1 . needle igure 7.1 or a spinal needle
NSAI s also provide good analgesia and bent to a degree angle is inserted midway
should be utili ed unless any contraindication between the lateral canthus and mid lower
is evident. eyelid. It is directed along the ventral orbit and

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