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under 50 years of age and in the parturient. Up to 90% of cases improve spontaneously within
10 days (Candido & Stevens, 2003).
For discussion of possible prevention and treatment see Section 9.6.5.
Treatment failure
Epidural analgesia may not always be successful due to a number of factors including catheter
malposition or displacement, or technical and patient factors resulting in an inability to
achieve effective analgesia. Intolerable side effects may also be an indication for premature
discontinuation. In a large prospective audit, 22% of patients had premature termination of
postoperative epidural infusions: the most common causes were dislodgement (10%) and
inadequate analgesia (3.5%), sensory or motor deficit (2.2%). Most of these failures occurred
on or after postoperative day 2 (Ballantyne et al, 2003 Level IV). These outcomes supported
similar findings by Burstal et al (Burstal et al, 1998 Level IV) and reinforce the need for strategies
to support epidural analgesia as part of a multimodal approach to acute pain management.
Other
There has been concern among surgeons about increased risk of anastomotic leakage after
bowel surgery due to the stimulating effects of epidural administration of local anaesthetics;
so far there is no evidence to support these claims (Holte & Kehlet, 2001 Level I).
Key messages
1. Thoracic epidural analgesia for open abdominal aortic surgery reduces the duration of
tracheal intubation and mechanical ventilation, as well as the incidence of myocardial
infarction, acute respiratory failure, gastrointestinal complications and renal insufficiency
(N) (Level I [Cochrane]).
2. For all types of surgery, epidural analgesia provides better postoperative pain relief
compared with parenteral (including PCA) opioid administration (S) (Level I [Cochrane
review]); except epidural analgesia using a hydrophilic opioid only (N) (Level I).
3. High thoracic epidural analgesia used for coronary artery bypass graft surgery reduces CHAPTER 7
postoperative pain, risk of dysrhythmias, pulmonary complications and time to extubation
when compared with IV opioid analgesia (N) (Level I).
4. Epidural local anaesthetics improve oxygenation and reduce pulmonary infections and
other pulmonary complications compared with parenteral opioids (S) (Level I).
5. Thoracic epidural analgesia improves bowel recovery after abdominal surgery (including
colorectal surgery (S) (Level I).
6. Thoracic epidural analgesia extended for more than 24 hours reduces the incidence of
postoperative myocardial infarction (U) (Level I).
7. Epidural analgesia is not associated with increased risk of anastomotic leakage after bowel
surgery (U) (Level I).
8. Chlorhexidine‐impregnated dressings of epidural catheters in comparison to placebo‐ or
povidone‐iodine‐impregnated dressings reduce the incidence of catheter colonisation (N)
(Level I).
9. The use of continuous background epidural infusion combined with PCEA results in
improved maternal analgesia and reduced unscheduled clinician interventions (N) (Level I).
10. Thoracic epidural analgesia reduces need for ventilation in patients with multiple rib
fractures (S) (Level I) and reduces incidence of pneumonia (U) (Level II).
Acute pain management: scientific evidence 189
