A systematic review of the analgesic efficacy and adverse effects of epidural morphine versus parenteral morphine after caesarean section

1
A systematic review of the analgesic efficacy and
adverse effects of epidural morphine versus
parenteral morphine after caesarean section

• Carmen KM Chan1
• Sui Cheung Yu1, Anna Lee2
• Department of Anaesthesiology, Pain Medicine and
  Operating Services, United Christian Hospital,
  Hong Kong
• Department of Anaesthesia and Intensive Care, The
  Chinese University of Hong Kong, Hong Kong

2
Caesarean section and pain relief

• Epidural morphine
• Better than intermittent parenteral opioids
• Parenteral morphine
• IV PCA good practice
• NICE CG 13 (2004)
• ASA Practice Guidelines (2007)
• ANZCA FPM Acute Pain Management Scientific
  Evidence (2010)

3
Objectives

• Compare
• epidural versus parenteral morphine for pain
  relief after caesarean section
• efficacy
• side effects

4
Pre-determined search strategy and selection
criteria

• MeSH, keywords
• CENTRAL
• Medline
• EMBASE

• Exclude
• Labour analgesia
• Sustained-release EM

5
Quality assessment of the studies
Domain based approach
Cochrane Handbook for Systematic Reviews of
Interventions (2008)
6
Outcomes
Primary
VAS (0-10) 12 hours VAS (0-10) 24 hours
Secondary
Mean total morphine usage in first 24 hours No. of patients requiring supplementary analgesics in first 24 hours Incidence of side effects Vomiting Pruritus Respiratory depression Urinary retention Patient satisfaction
7
Data extraction and analysis
Data extraction
Available case analysis
RevMan
Random effects modelling
Continuous WMD 95 CI
Dichotomous OR 95 CI
8
Results
Database and reference search 538

• Included
• 12 trials
• 1427 patients

• Excluded
• 526 reports

9
Quality of the trials was variable
10
Epidural morphine lower VAS 12 hours
WMD -1.39 -1.75, -1.02 (Plt0.001)
Pan 1994
Rapp-Zingraff 1997
-4
0
2
-2
4
Favours EM
Favours PM
Heterogeneity Tau20.03 Chi21.74, df1
(P0.19) I243
11
No difference in VAS at 24 hours
WMD -0.54 -1.60, 0.51 (P0.31)
Pan 1994
Rapp-Zingraff 1997
-4
0
2
-2
4
Favours EM
Favours PM
Heterogeneity Tau20.46 Chi24.37, df1
(P0.04) I277
12
Less morphine (mg) usage in 24 hours
WMD -30.02 -38.82, -20.22 (Plt0.001)
Cohen 1983
Coombs 1982
Eisenach 1988
Youngstrom 1982
0
-50
-100
50
100
Favours EM
Favours PM
Heterogeneity Tau260.72 Chi28.75, df3
(P0.03) I266
13
Less supplementary analgesics and more pruritus
Supplementary analgesics (3 trials)1
Pruritus (11 trials)2
10
10
OR 6.07 3.10, 11.86 Plt0.001
1
1
OR 0.30 0.12, 0.73 P0.008
0.1
0.1
1Heterogeneity Tau20.00 Chi21.90, df2
(P0.39) I20 2Heterogeneity Tau20.58
Chi227.18, df10 (P0.002) I263
14
Other secondary outcomes

• Inadequate data
• Vomiting
• Respiratory depression
• Urinary retention
• Patient satisfaction
• Outcome measures too heterogeneous

15
Summary

• Benefits
• Epidural morphine gives better analgesia in the
  first 12 hours
• Less morphine and supplementary analgesics
  inferring better analgesia at 24 hours
• Harm More pruritus
• Implication for clinical practice ?optimal dose

16
A systematic review of the analgesic efficacy and
adverse effects of epidural morphine versus
parenteral morphine after caesarean section

• Carmen KM Chan1
• Sui Cheung Yu1, Anna Lee2
• Department of Anaesthesiology, Pain Medicine and
  Operating Services, United Christian Hospital,
  Hong Kong
• Department of Anaesthesia and Intensive Care, The
  Chinese University of Hong Kong, Hong Kong

17
Limitations

• Publication bias is possible
• Quality of the primary studies was poor (?studies
  with all domain rated yes)
• Other side effects not included
• Patient satisfaction too heterogeneous

18
Similar findings with recent SR

• EM decreased pain scores and postoperative
  morphine request during the first 24 hours
• EM increased incidence of pruritus (RR 2.7 95
  CI, 2.13.6) and nausea (RR 2.0 95 CI,
  1.23.3).

Bonnet MP, Mignon A, et al. European Journal of
Pain (2010)