In this section, data are available from studies that assessed pre-operative analgesia versus pre-operative placebo…
In this section, data are available from studies that assessed pre-operative analgesia versus pre-operative placebo, as well as those that examine the concept of pre-emptive – or preventive – analgesia, assessed pre-operative analgesia versus the same analgesia given postoperatively.
A previous systematic review of pre-emptive analgesia for postoperative pain relief in a variety of surgical procedures – such as orthopaedic, dental, gynaecological and abdominal – concluded that there is no benefit of pre-emptive over postoperative administration (Møiniche 2002). More recently, a meta-analysis of studies comparing pre-operative interventions with similar postoperative interventions in various procedures, found that pre-operative epidural analgesia was effective in reducing postoperative pain scores, but that pre-operative NSAIDs, local anaesthetic wound infiltration, NMDA antagonists and opioids did not improve postoperative analgesia (Ong 2005b).
Despite these findings, it is considered that analgesic medication needs to be initiated in time to ensure an adequate analgesic effect in the immediate postoperative period. This may necessitate administration prior to the postoperative period.
There were no significant differences between the spinal morphine and spinal morphine + sufentanil groups for VAS pain scores at rest and coughing during the first 48 h postoperatively (n=77)
There was no significant difference in postoperative PCA morphine consumption with spinal morphine versus spinal morphine + sufentanil in the PACU, or at 24 or 48 h postoperatively (n=77)
Intra-operative IV sufentanil requirements were similar in the spinal morphine and spinal morphine + sufentanil groups (n=77)
There was no significant difference in patient satisfaction (VAS scale 1–100) with pre-operative spinal morphine versus spinal morphine + sufentanil (n=77)
Incidence of postoperative nausea and vomiting was similar between the pre-operative spinal morphine group and the pre-operative spinal morphine + sufentanil group (n=77)
Spinal bupivacaine conferred no significant benefit over placebo for reducing VAS pain scores at rest, mobilisation or during coughing at any of the time points assessed (2, 6 and 12 h, Days 1, 2 and 3) (n=40)
Spinal clonidine conferred no significant benefit over spinal bupivacaine for reducing VAS pain scores at rest, mobilisation or during coughing at any of the time points assessed (2, 6 and 12 h, Days 1, 2 and 3) (n=40)
The incidence of intra-operative adverse haemodynamic events was significantly greater with pre-operative spinal clonidine compared with pre-operative spinal bupivacaine or placebo (p<0.05) (n=20/group)