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11. The combination of thoracic epidural analgesia with local anaesthetics and nutritional
support leads to preservation of total body protein after upper abdominal surgery (U)
(Level II).
12. The risk of permanent neurological damage in association with epidural analgesia is very
low; the incidence is higher where there have been delays in diagnosing an epidural
haematoma or abscess (S) (Level IV).
13. Immediate decompression (within 8 hours of the onset of neurological signs) increases the
likelihood of partial or good neurological recovery (U) (Level IV).
The following tick boxes represent conclusions based on clinical experience and expert
opinion.
The provision of epidural analgesia by continuous infusion or patient‐controlled
administration of local anaesthetic‐opioid mixtures is safe on general hospital wards, as
long as supervised by an anaesthesia‐based pain service with 24‐hour medical staff cover
and monitored by well‐trained nursing staff (U).
Magnetic resonance imaging investigation may be warranted if patients who have had an
epidural catheter inserted develop a fever and infection at the catheter insertion site;
urgent investigation is especially indicated if other signs are present that could indicate an
abscess, such as back pain or neurological change (N).
7.3 INTRATHECAL ANALGESIA
7.3.1 Drugs used for intrathecal analgesia
CHAPTER 7 Local anaesthetics given intrathecally provide only short‐term postoperative analgesia.
Local anaesthetics
The use of spinal microcatheters (<24 gauge) for postoperative infusions of local anaesthetics
became controversial when multiple cases of cauda equina syndrome were reported
(Bevacqua, 2003). See also Section 5.1.3.
Opioids
Intrathecal opioids have been used for surgical procedures ranging from lower limb
orthopaedic surgery to CABG because of their ability to provide prolonged postoperative
analgesia following a single dose. Clinical experience with morphine, fentanyl and sufentanil
has shown no neurotoxicity or behavioural changes at normal intrathecal doses (Hodgson et al,
1999 Level IV).
Intrathecal morphine produces analgesia lasting 12 hours or more. Side effects include
respiratory depression, nausea, vomiting and pruritus. Early clinical studies used very high
intrathecal morphine doses (ie 0.5 mg or more), however adequate postoperative analgesia
with fewer adverse effects may be obtained with significantly less morphine — although at
lower doses there is not a clear dose‐response relationship for some side effects or analgesia
(Meylan et al, 2009 Level I). A meta‐analysis comparing intrathecal morphine doses of less than
300 mcg, equal to or greater that 300 mcg, and placebo reported a greater risk of respiratory
depression with the higher doses of morphine (there was no increased risk with lower
morphine doses) and while the incidence of pruritus was increased for all doses, the risk of
nausea and vomiting was increased only in those patients given less than 300 mcg morphine
(Gehling & Tryba, 2009 Level I).
190 Acute Pain Management: Scientific Evidence
