Page 232 Acute Pain Management

in improved bowel recovery after abdominal surgery, while these benefits were not consistent
with lumbar administration (Steinbrook, 1998; Jorgensen et al, 2000 Level I). If epidural analgesia
was extended for more than 24 hours, a further benefit was a significant reduction in the
incidence of postoperative myocardial infarction (Beattie et al, 2001 Level I). Benefits of epidural
analgesia after abdominal aortic surgery were found in particular with TEA (Nishimori et al, 2006
Level I). A comparison of TEA and lumbar epidural administration in patients undergoing
gynaecological surgery showed that TEA provided better pain relief only when the incision
extended above the umbilicus and led to less motor block but more pruritus (Richman et al,
2007 Level II).
In patients with multiple traumatic rib fractures, provision of TEA with local anaesthetics has
been shown to reduce the duration of ventilation compared with other forms of analgesia
(including lumbar epidural analgesia); although mortality and length of ICU stay was not
different in pooled analysis of all routes of epidural administration versus parenteral opioids,
and hypotension was more frequent in the epidural groups when TEA with local anaesthetics
was used (Carrier et al, 2009 Level I). In one study, the risk of nosocomial pneumonia was
reduced by TEA compared with parenteral opioids (Bulger et al, 2004 Level II).
7.2.2 Drug used for epidural analgesia
Differences in effects and adverse effects can be found with the local anaesthetics, opioids and
various adjuvant drugs used in epidural analgesia.
Local anaesthetics
For epidural infusions, dose‐ranging studies established that 0.2% ropivacaine was a suitable
concentration (Scott et al, 1995 Level II; Schug et al, 1996 Level II). Therefore, most investigators
compare infusions of bupivacaine or levobupivacaine at 0.1% or 0.125% with ropivacaine
0.2%, which removes any imbalance in comparative potency.
CHAPTER 7 For more information on differences in efficacy and adverse effects between the local
anaesthetics used for epidural analgesia see Section 5.1.2.
Opioids
Opioids alone via the epidural route seem to be of limited benefit. In particular, when
administered via a thoracic approach, opioids failed to demonstrate any advantage over
parenteral opioids except for a slight reduction in the rate of atelectasis (Ballantyne et al, 1998
Level I); there is no benefit on bowel recovery (Steinbrook, 1998; Jorgensen et al, 2000 Level I). On
the basis of the available studies, the benefits of administering lipophilic opioids alone by the
epidural route would appear to be marginal, or unproven in the case of upper abdominal
surgery, and in many situations will not outweigh the risks of the more invasive route of
administration (for detailed discussion see Wheatley et al, 2001 and Section 5.2.1).
For information on the epidural use of morphine, extended‐release morphine, pethidine,
fentanyl, alfentanil, sufentanil, diamorphine and hydromorphone see Section 5.2.1.
Local anaesthetic-opioid combinations
Combinations of low concentrations of local anaesthetic agents and opioids have been shown
to provide consistently superior pain relief compared with either of the drugs alone (Curatolo et
al, 1998 Level I). Addition of fentanyl to a continuous epidural infusion of ropivacaine reduced
the rate of regression of sensory block (Kanai et al, 2007 Level II) and decreased the
discontinuation of postoperative epidural infusion due to lack of efficacy (Scott et al, 1999
Level II).
For more information on the epidural use of different local anaesthetic‐opioid drug
combinations see Section 5.2.1.
184 Acute Pain Management: Scientific Evidence