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 methods
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.

Authors' 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.

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

SPINAL anesthesia is commonly used for cesarean section, and it has become a popular practice to add opioids to spinal solutions to enhance and prolong intraoperative and postoperative analgesia. Morphine and fentanyl are the opioids most often used for this purpose, but there is not a general consensus about the benefits of the various regimens, and the incidence of side effects with different opioids and doses is controversial. Recently, a number of systematic reviews have been published in the field of pain and perioperative medicine. The aim of a systematic review is to summarize available information from controlled clinical trials to produce evidence-based estimates of the true clinical effect of an intervention. The purpose of this systematic review was to investigate the effect of intrathecal opioids added to spinal anesthesia on intraoperative and postoperative pain and to evaluate adverse effects in patients scheduled for cesarean section, using evidence from all relevant randomized controlled and blinded trials.

Intraoperative and postoperative analgesic efficacy and adverse effects of intrathecal opioids in patients undergoing cesarean section with spinal anesthesia: a qualitative and quantitative systematic review of randomized controlled trials.

ANESTHESIA has become remarkably safe, and while death and permanent damage have become rare occurrences, other sequelae of anesthesia are gaining more importance. Postoperative nausea and vomiting (PONV) still is the most troublesome adverse event encountered in the recovery room, despite advances in prevention and treatment. The incidence of PONV has remained high and has a major negative impact on patient satisfaction about the overall surgical experience. Furthermore, the ongoing trend toward ambulatory procedures has increased the focus on PONV as its occurrence may delay discharge or cause unanticipated hospital admission. General anesthesia has long been considered as causing a greater frequency and severity of PONV than regional anesthetic techniques. Recent studies investigating this time-honored dictum in a controlled manner mostly, but not unanimously, confirmed it. Accordingly, considerable effort has been invested to examine etiology, define patients at risk, and outline preventive and therapeutic strategies in patients undergoing general anesthesia. Reviews dealing with PONV have discussed almost exclusively general anesthesia and largely ignored regional anesthesia. This contrasts with the increasing popularity of regional anesthesia. A survey in Europe showed that one third of patients are undergoing regional anesthesia for their operative procedure. In France, the proportion of regional anesthesia increased from 15 to 25% of all anesthetics administered from 1980 to 1996. The number of local anesthetic and analgesic agents available for regional anesthesia has increased over the last two decades. Since the introduction of intrathecal and epidural morphine in 1979, a multitude of medications, such as synthetic opioids, 2-agonists, and cholinesterase inhibitors, have been introduced in an attempt to enhance the action of local anesthetics. The decision about their usefulness will not only rely on their effects on nerve blockade and pain relief, but also on their influence on side effects such as PONV. This review focuses on PONV in the setting of perioperative regional anesthesia. General aspects of PONV, such as physiology, patient, and perioperative factors involved are discussed. Few studies regarding these issues have been specifically devoted to regional anesthesia. Therefore, much information must be derived from investigations of general anesthesia. Specific regional anesthetic techniques and the influence of adjunctive medications on PONV are also presented. Combined general–regional anesthesia is purposefully excluded, avoiding the many variables introduced by general anesthesia. A final section is devoted to continuous peripheral nerve blocks and their possible impact on PONV.

Postoperative nausea and vomiting in regional anesthesia: a review.

We compared the effects of intrathecal sufentanil 2.5 and 5 micro g, fentanyl 10 micro g, and placebo when administered together with hyperbaric bupivacaine 0.5% 12.5 mg for cesarean section. The study was performed in a randomized, double-blind fashion in 80 (20 per group) healthy, full-term partur

Intrathecal Sufentanil, Fentanyl, or Placebo Added to Bupivacaine for Cesarean Section

https://rapm.bmj.com/content/rapm/25/3/240.full.pdf

Bupivacaine-sparing effect of fentanyl in spinal anesthesia for cesarean delivery.

We have used both spinal and extradural anaesthesia with a 26-gauge, long spinal needle through a 16-gauge Tuohy needle for elective Caesarean section. Four different subarachnoid solutions of bupivacaine were compared: 0.5% heavy bupivacaine alone, or with adrenaline, fentanyl or adrenaline and fentanyl. The incidence of complications and time of regression of the sensory block were analysed. The technique is recommended because it allows rapid onset of anaesthesia and the advantages of an extradural catheter. The subarachnoid solution of choice was 0.5% heavy bupivacaine 12.5 mg with fentanyl 10 μg

D.A. Browne

Papers

Comparison of four subarachnoid solutions in a needle-through-needle technique for elective caesarean section