Epidural local anaesthetics versus opioid-based analgesic regimens on postoperative gastrointestinal paralysis, PONV and pain after abdominal surgery.

BACKGROUND: Gastrointestinal paralysis, nausea and vomiting, and pain, are major clinical problems following abdominal surgery. Anaesthetic and analgesic techniques that reduce pain and postoperative nausea and vomiting (PONV), and prevent or reduce postoperative ileus, may reduce postoperative morbidity, duration of hospitalisation and hospital costs.
OBJECTIVES: To compare effects of postoperative epidural local anaesthetic with regimens based on systemic or epidural opioids, on postoperative gastrointestinal function, postoperative pain, PONV and surgical/anaesthetic complications. SEARCH STRATEGY: Trials were identified by computerised searches of the Cochrane Controlled Trials Register, MEDLINE, EMBASE and by checking the reference lists of trials and review articles. SELECTION CRITERIA: Randomised controlled trials comparing the effects of postoperative epidural local anaesthetic with systemic or epidural opioids. DATA COLLECTION AND ANALYSIS: Collected data included treatment in active (local anaesthetic) and control (opioid based) groups, time to first postoperative stool, time to first postoperative flatus, gastric emptying measured by the paracetamol absorption test, duration of the passage of barium sulphate, pain assessments, use of supplementary analgesics, nausea, vomiting and surgical/anaesthetic complications. MAIN
RESULTS: Most studies in this review involved a small number of patients. Furthermore half of the studies indicated a poor level of methodology in particular regarding blinding and report of withdrawals. Heterogeneity of included studies was substantial. Results consistently showed reduced time to return of gastrointestinal function in the epidural local anaesthetic group compared with groups receiving systemic or epidural opioid (37 hours and 24 hours, respectively). Postoperative pain was comparable. Two studies compared the effect of epidural local anaesthetic with a combination of epidural local anaesthetic and opioid on gastrointestinal function. One study favoured epidural local anaesthetic and one study was indifferent. A meta analysis of five of eight studies comparing the effect of epidural local anaesthetic with a combination of epidural local anaesthetic and opioid on postoperative pain, yielded a reduction in VAS pain scores (0-100 mm) on the first postoperative day of 15 mm, in favour of the combination. No significant differences in PONV were observed between epidural local anaesthetic and opioid based regimens. REVIEWER'S
CONCLUSIONS: Administration of epidural local anaesthetics to patients undergoing laparotomy reduce gastrointestinal paralysis compared with systemic or epidural opioids, with comparable postoperative pain relief. Addition of opioid to epidural local anaesthetic may provide superior postoperative analgesia compared with epidural local anaesthetics alone. The effect of additional epidural opioid on gastrointestinal function is so far unsettled. Randomized, controlled trials comparing the effect of combinations of epidural local anaesthetic and opioid with epidural local anaesthetic alone on postoperative gastrointestinal function and pain are warranted.