High quality evidence suggests that an epidural anaesthetic (with or without an opioid) promotes the return of gut function after abdominal surgery. This is when compared to an opioid based regimen, given either through an epidural or into the bloodstream.
Epidural anaesthetic also gave a clinically meaningful reduction in pain. Evidence for other outcomes, including reduction in vomiting, was less reliable.
Poor gut function and pain in the period following abdominal surgery are common. Opioid pain-relief also carries additional risks. Improving these factors could theoretically have benefits in terms of reducing hospital stays and costs.
Ultimately, decisions to use epidural pain-relief over other methods should be made on a case-by-case basis. Implications for practice if epidural use is increased will include the need to train more ward nurses to manage postoperative epidural administration.
Why was this study needed?
Approximately 10% of people have temporary gut paralysis after open or keyhole abdominal surgery. Nausea, vomiting and pain are also common in the post-operative period. Return of gut function is normally required before hospital discharge. These factors can therefore prolong length of hospital stay and increase costs.
Possible ways to treat pain after abdominal surgery include inserting an epidural into the back and infusing local anaesthetic to numb the abdomen. Another option is to give injections of opioids (morphine-like substances). Opioids are known to slow bowel activity even at low doses, and at higher doses may cause breathing problems.
Epidural analgesia is thought to facilitate quicker return to normal bowel function and may reduce the need for opioids.
This updated Cochrane review compared the effects of giving an epidural anaesthetic with giving opioids after abdominal surgery. Opioids could either be injected directly into the bloodstream or given through an epidural.
What did this study do?
The review pooled the results of 94 randomised controlled trials including 5,846 adults undergoing any form of abdominal surgery under general anaesthesia. Treatment groups received an epidural containing local anaesthetic with or without opioids. Control groups received an opioid-based regimen, given either into the blood or through an epidural.
The main outcome of interest was return of gut function as measured by time to first flatus after surgery. Other outcomes included pain scores up to 72-hours post-surgery, vomiting within 24 hours, leakage where bowel sections were joined, length of hospital stay and costs.
The included trials were of mixed quality ranging from very low to high quality. Common sources of bias involved treatment allocation, and patients and assessors being aware of pain-relief given. Only six were conducted in the UK.
What did it find?
- High quality evidence from 22 trials (1,138 participants) found an epidural containing local anaesthetic decreased the time to return of gut function by approximately 17.5 hours compared with an opioid-based regimen (standardised mean difference [SMD] -1.28, 95% CI -1.71 to -0.86). There was high variability in the results of the individual studies, but subgroup analyses did not significantly affect the result. For example, the effect was the same regardless of type of abdominal surgery, or whether or not an opioid was added to the epidural.
- Moderate quality evidence from 35 trials (2,731 participants) found an epidural containing local anaesthetic reduced pain on movement 24 hours after surgery (SMD -0.89, 95% CI -1.08 to -0.70). This was equivalent to a reduction of 2.5 on a pain scale from 0 to 10, and seen for all types of abdominal surgeries.
- Low quality evidence found that an epidural with local anaesthetic did not affect the likelihood of vomiting (risk ratio [RR] 0.84, 85% CI 0.57 to 1.23; 22 trials) or of leakage where bowel sections had been joined together (RR 0.74, 95% CI 0.41 to 1.32; 17 trials).
- Very low quality evidence from 30 trials (2,598 participants) found that epidural analgesia reduced the time spent in hospital after open surgery by one day (SMD -0.20, 95% CI -0.35 to -0.04).
- Only two small studies provided any information on comparative costs.
What does current guidance say on this issue?
There is no specific NICE guidance on the use of epidural anaesthesia or opioid injections following abdominal surgery.
In 2000, a US Joint Commission on Accreditation of Healthcare Organizations (JCAHO) stated that under-treatment of pain after surgery would constitute abrogation of a fundamental human right. An increase in the use of opioids for acute postoperative pain was observed in the US following the release of this statement, as was an increase in their side effects.
What are the implications?
This updated review provides high quality evidence that an epidural anaesthetic (with or without an opioid) accelerates return to normal bowel function following abdominal surgery. It may also have a clinically meaningful effect on pain. However, evidence for other outcomes was less reliable.
Decisions to use epidural analgesia over other methods of pain-relief following abdominal surgery must be made on a case-by-case basis taking into account patient factors, type of surgery and postoperative ward facilities.
Implications for practice of an increase in epidural use will include nurse training in administering epidural pain-relief on the postoperative ward.
Citation and Funding
Guay J, Nishimori M, Kopp S. Epidural local anaesthetics versus opioid-based analgesic regimens for postoperative gastrointestinal paralysis, vomiting and pain after abdominal surgery. Cochrane Database Syst Rev. 2016;7:CD001893.
This project was funded by the Canadian Universities of Abitibi Temiscamingue and Montreal.
White PF, Kehlet H. Improving pain management: are we jumping from the frying pan into the fire? Anesth Analg. 2007;105(1):10-2.
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