Page 30 Acute Pain Management

8. There is no analgesic benefit in adding naloxone to the PCA morphine solution; however
in ultra‐low doses the incidence of nausea and pruritus may be decreased (U) (Level II).
9. The addition of a background infusion to intravenous PCA does not improve pain relief or
sleep, or reduce the number of PCA demands (U) (Level II).

10. Subcutaneous PCA opioids can be as effective as intravenous PCA (U) (Level II).
11. Intranasal PCA opioids can be as effective as intravenous PCA (U) (Level II).
12. The risk of respiratory depression with PCA is increased when a background infusion is
used (U) (Level IV).
SUMMARY  Adequate analgesia needs to be obtained prior to commencement of PCA. Initial

orders for bolus doses should take into account individual patient factors such as a
history of prior opioid use and patient age. Individual PCA prescriptions may need to be
adjusted (U).
 The routine addition of antiemetics to PCA opioids is not encouraged, as it is of no
benefit compared with selective administration (U).
 PCA infusion systems must incorporate antisyphon valves and in non‐dedicated lines,
antireflux valves (U).
 Drug concentrations should be standardised within institutions to reduce the chance of
programming errors (U).
 Operator error remains a common safety problem (N).

Epidural analgesia
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
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).

xxx Acute Pain Management: Scientific Evidence