Page 180 Acute Pain Management

Plexus block
There is evidence of analgesic benefit with the addition of clonidine to local anaesthetics for
brachial plexus blocks (Murphy et al, 2000 Level I) but many of the studies have methodological
limitations.
Clonidine improved duration of analgesia and anaesthesia when used as an adjunct to local
anaesthetics for axillary and peribulbar blocks; side effects appeared to be limited at doses up
9
to 150 mcg (McCartney et al, 2007 Level I ). The addition of clonidine to local anaesthetic
solutions used for single‐shot peripheral nerve or plexus blocks also prolonged duration of
analgesia and motor block (Popping et al, 2009 Level I). The effects of the addition of clonidine to
lignocaine were similar to those of adding adrenaline in cervical plexus blockade in terms of
block onset and duration, although lignocaine absorption was faster when clonidine was used
(Molnar et al, 1997 Level II). Addition of clonidine to a popliteal fossa nerve block with
bupivacaine did not result in any difference in pain relief but did prolong the analgesic effects
(YaDeau et al, 2008 Level II). There was no difference in pain relief when clonidine was added to
a continuous femoral nerve infusion with ropivacaine (Casati et al, 2005 Level II).
The use of clonidine with local anaesthetic or opioid also extended analgesia with thoracic
paravertebral blocks (Bhatnagar et al, 2006 Level II; Burlacu et al, 2006 Level II).
Evidence is lacking for the use of clonidine as an adjunct to local anaesthetics for continuous
9
catheter techniques (McCartney et al, 2007 Level I ).
Intravenous regional anaesthesia
CHAPTER 5 Addition of dexmedetomidine to lignocaine IV regional anaesthesia (IVRA) increased duration

and quality of analgesia (Memis et al, 2004 Level II). Clonidine was effective in delaying
tourniquet pain with IVRA in volunteers (Lurie et al, 2000 Level III‐2).
Intra-articular
The use of intra‐articular clonidine on its own or in addition to local anaesthetic agents
improved analgesia after knee joint arthroscopy and decreased opioid consumption (Brill &
Plaza, 2004 Level II; Alagol et al, 2005 Level II).
Intra‐articular dexmedetomidine resulted in a longer duration of pain relief compared with IV
dexmedetomidine (Al‐Metwalli et al, 2008 Level II).
5.3.2 Adrenaline

Neuraxial
In postoperative thoracic epidural infusions, the addition of adrenaline (epinephrine) to
fentanyl and ropivacaine or bupivacaine improved analgesia (Sakaguchi et al, 2000 Level II; Niemi
& Breivik, 2002 Level II; Niemi & Breivik, 2003 Level II). This was not demonstrated with lumbar
epidural infusions (Forster et al, 2003 Level II). The efficacy of thoracic epidural pethidine
infusions after thoracotomy was not improved by addition of adrenaline (Bryson et al, 2007
Level II).
The addition of adrenaline (0.2 mg) to intrathecal bupivacaine prolonged motor block and
some sensory block modalities (Moore JM et al, 1998 Level II).

9
This systematic review includes a study or studies that have since been withdrawn from publication. Please refer to
the Introduction at the beginning of this document for comments regarding the management of retracted articles.
Marret et al (Marret et al, Anesthesiology 2009; 111:1279–89) re‐examined the data included in this review and
concluded that exclusion of data obtained from the retracted publications did not significantly alter the results.
132 Acute Pain Management: Scientific Evidence