Local anaesthetic wound infiltration and abdominal nerves block during caesarean section for postoperative pain relief.

BACKGROUND: Caesarean section delivery is becoming more frequent. Childbirth is an emotion-filled event and the mother needs to bond with her newborn baby as early as possible. Any intervention that leads to improvement in pain relief is worthy of investigation. Local anaesthetics, either on their own or in combination with opioids or nonsteroidal antiinflammatory drugs, have been employed as an adjunct to other postoperative pain relief strategies. Conflicting reports were noted.

OBJECTIVES: To assess the effects of local anaesthetic agent wound infiltration/irrIgation and/or abdominal nerve blocks on post-caesarean section pain and the mother's well being and interaction with her baby.

SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2009).

SELECTION CRITERIA: Randomised controlled trials of pre-emptive local analgesia during caesarean section.

DATA COLLECTION AND ANALYSIS: One author extracted data. The second author checked the data.

MAIN RESULTS: Twenty studies (1150 women) were included. Women who had caesarean section performed under regional analgesia and had wound infiltration had a decrease in morphine consumption at 24 hours (SMD -1.70mg; 95% confidence interval (CI) -2.75 to -0.94) compared to placebo.In women under general anaesthesia, with caesarean section wound infiltration and peritoneal spraying with local anaesthetic (one study, 100 participants), the need for opioid rescue was reduced (risk ratio (RR) 0.51; 95% CI 0.38 to 0.69). The numerical pain score (0 to10) within the first hour was also reduced (mean difference (MD) -1.46; 95% CI -2.60 to -0.32).Women with regional analgesia who had local anaesthetic and non-steriodal anti-inflammatory cocktail wound infiltration consumed less morphine (one study, 60 participants; MD -7.40 mg; 95% CI -9.58 to -5.22) compared to local anaesthetic control.Women who had regional analgesia with abdominal nerves blocked had decreased opioid consumption (four studies, 175 participants; MD -25.80 mg; 95% CI -50.39 to -5.37).For the outcome of visual analogue scale 0 to 10 over 24 hours, no advantage was demonstrated in the single study of 50 participants who had wound infiltrated with a mixture of local analgesia and narcotics versus local analgesia.Addition of ketamine to the local analgesia in women who had regional analgesia does not confer any advantage.

AUTHORS' CONCLUSIONS: Local analgesia infiltration and abdominal nerve blocks as adjuncts to regional analgesia and general anaesthesia are of benefit in caesarean section by reducing opioid consumption. Nonsteroidal anti-inflammatory drugs as an adjuvant may confer additional pain relief.