Page 249 Acute Pain Management

Topical tetracaine, liposome‐encapsulated tetracaine, and liposome‐encapsulated lignocaine
were as effective as EMLA® cream for dermal instrumentation analgesia in the emergency
department (Eidelman et al, 2005 Level I). See Section 10.4.2 for use in children and Section 9.9.2
for use in the emergency department.
Topical local anaesthetic provided no analgesic benefit when performing flexible diagnostic
nasoendoscopy, either alone or in combination with a vasoconstrictor (Conlin & McLean, 2008
Level I; Nankivell & Pothier, 2008 Level I).
Intraurethral instillation of lidocaine gel provides superior analgesia to lubricating gel during
flexible cystoscopy (Aaronson et al, 2009 Level I).
Following tonsillectomy, local anaesthetics provided a modest reduction in post‐tonsillectomy
pain; administering the local anaesthetic on swabs appeared to provide a similar level of
analgesia to that of infiltration (Grainger & Saravanappa, 2008 Level I).
A meta‐analysis concludes that there is insufficient evidence to recommend topical lignocaine
as a first‐line agent in the treatment of postherpetic neuralgia with allodynia (Khaliq et al, 2007
Level I).

7.5.5 Safety
Anticoagulation
Caution should be applied in the use of some peripheral nerve or plexus blocks in patients with
impaired coagulation (see Section 7.4.2)
Nerve injury
An ASRA&PM Practice Advisory publication (Neal et al, 2008 Level IV) provides a good overview
of and guidance on neurological complications in regional anaesthesia, importantly noting that
most symptoms resolve within days to weeks and that many factors unrelated to the block
itself may contribute perioperative nerve injury (Welch et al, 2009 Level IV; Neal et al, 2008
Level IV).
Most nerve injury after these techniques presents as residual paraesthesia and rarely as CHAPTER 7
permanent paralysis (persisting for more than 6 to 12 months). A review of data from
published studies of the risk of neurological injury associated with epidural and other regional
anaesthesia and analgesia differentiated between the risk of permanent neurological injury
and transient neuropathy (Brull et al, 2007 Level IV). The incidence of transient neuropathy
(radiculopathy) after three common forms of peripheral nerve blockade — interscalene
brachial plexus block, axillary brachial plexus block and femoral nerve block — was estimated
to be 2.84%, 1.48% and 0.34% respectively.
A review of 1416 patients after CPNB for orthopaedic surgery reported three patients with
nerve lesions (all after femoral nerve CPNB); full recovery was seen within 10 weeks (Capdevila
et al, 2005 Level IV). Another prospective audit of 1065 patients after CPBN reported a similar
block‐related neuropathy rate of 0.22% (Watts & Sharma, 2007 Level IV).
The risk of permanent neurological injury (lasting over 12 months) after peripheral neural
blockade was much lower. In all the studies included in this review, only one case was
reported (out of 22 414 cases with follow‐up data recorded), making it a very rare event
(Brull et al, 2007 Level IV). The Australasian Regional Anaesthesia Collaboration (ARAC) followed
up 6069 patients who received 7156 peripheral nerve blocks for neurological and other
complications. The incidence of late neurological deficit was 0.4:1000 procedures
(Barrington et al, 2009 Level IV).

Acute pain management: scientific evidence 201