Abstract: BACKGROUND: Ample evidence is now available showing the analgesic efficacy of a local anaesthetic-opioid combination to control postoperative pain. This retrospective study aimed to analyze any improvement in the ability of sufentanyl, a highly lipophilic opioid, and morphine, a poorly lipophilic opioid, to control postoperative pain at rest and in motion when combined with ropivacaine 0.2%. METHODS: In this retrospective study, 171 patients who underwent major abdominal or urological surgery were evaluated. The therapeutic protocol provided for continuous epidural perfusion (5 mL/h) of ropivacaine 0.2% + morphine 0.03 mg/mL or ropivacaine 0.2% + sufentanyl 0.75 mug/mL for 48 h. Pain at rest (numeric rate scale, NRS) and in motion (NRSm) was evaluated by means of the NRS upon waking and at 3, 6, 12, 24, 36, and 48 hs, providing for the administration of a rescue dose if NRS >4. The overall analgesic effect was evaluated by comparing the area under the NRS curve (AUC) of both treatments using the Mann Whitney U test. Any differences between treatments in terms of NRS and NRSm in time were evaluated using ordinal logistic regression. To compare the frequency of patients who reported NRS >4 at least once during the follow-up period, logistic regression was used. Finally, the frequency of patients who required at least one additional drug or reported side effects was compared using Fisher's exact test. RESULTS: While both groups showed a comparable overall analgesic effect, the baseline values of NRS and NRSm were lower for the sufentanyl group (P<0.001), perhaps as a result of its quicker onset due to higher lipophilicity. No statistically significant difference was observed in the frequency of patients requiring administration of an additional analgesic drug (P=0.136) or in the incidence of complications (P=0.799). CONCLUSION: Both protocols providing a combination of a local anaesthetic and an opioid demonstrated an excellent safety and efficacy profile. The differing lipophilicity of the opioids did not cause any clinically or statistically significant differences in terms of efficacy or safety, other than a reduced onset time of sufentanyl, ensuring better pain control upon waking. We therefore believe that morphine should be the standard opioid for neuraxial use, although these results must be confirmed in the setting of a randomized controlled clinical trial.
Abstract: Although regional anaesthesia has become safer, there are an increasing number of articles regarding complications of regional blocks. During the last few years, many authors have suggested the use of ultrasound to minimize the appearance of complications. This review was performed, through a Medline research, to evaluate articles concerning ultrasound and locoregional anaesthesia published until April 2005. A total of 39 articles were reviewed. Technical procedures, the use of ultrasound guidance in epidural anesthesia, the application of this technique for peripheral nerve blocks, and its indications in pregnancy and in pediatric patients were considered. In these articles, all of the authors focused on the advantages of ultrasound guidance. With the help of this technique, correct catheter placement as close to the target as possible was obtained; the spread of local anesthetic administered around the nerve and its roots can be visualized, reducing the doses needed; in addition, it is possible to avoid the most common complications, such as intravascular injection, dura mater puncture, hematoma formation, and nerve injury. Ultrasound guidance is useful in facilitating peripheral and neuroaxial blocks and offers direct visualization of the target, adjacent structures, and local anesthetic spread. The advantages also include a decreased rate of complications and faster onset of blocks. Finally, ultrasound measurements can even result in suggestions to modify established block technique.
