Benefits, risks, and best practice in regional anesthesia: do we have the evidence we need?

For more than 25 years, regional anesthesia has challenged anesthesiologists to determine whether it offers real benefits in terms of patient outcome from major surgery, compared with general anesthesia. Although there is good evidence that regional analgesia offers superior pain relief to systemic opioid analgesia, evidence to support improved outcome from surgery remains elusive. Although many publications appear to support the hypothesis, others show no benefit, and the lack of properly conducted, large studies makes it difficult to draw any evidence-based conclusions in favor of regional anesthesia. Given that all major regional techniques have the potential to cause significant risks to patient outcome, it is incumbent on all anesthesiologists to balance the intended benefits against the significant adverse events associated with regional techniques. We are beginning to develop an evidence base for both the benefits and risks of regional anesthesia, when used for specific patient groups and for specific surgical procedures. This presentation looks at some of the evidence and examines how it can be used to develop guidelines for best practice.

Is smaller necessarily better? A systematic review comparing the effects of minilaparoscopic and conventional laparoscopic cholecystectomy on patient outcomes.

BACKGROUND: In recent years, minilaparoscopic cholecystectomy (MLC; total size of trocar incision < 25 mm) has been increasingly advocated for the removal of the gallbladder, due to potentially better surgical outcomes (e.g., better cosmetic result, reduced pain, shorter hospital stay, quicker return to activity), but an evidence-based approach has been lacking. The current systematic review was undertaken to evaluate the importance of total size of trocar incision in improving surgical outcomes in adult laparoscopic cholecystectomy (LC). METHODS: The literature was systematically reviewed using MEDLINE and EmBASE. Only randomized controlled trials in English, investigating minilaparoscopic versus conventional LC (total size of trocar incision > or = 25 mm) and reporting pain scores were included. Quantitative analyses (meta-analyses) were performed on postoperative pain scores and other patient outcomes from more than one study where feasible and appropriate. Qualitative analyses consisted of assessing the number of studies showing a significant difference between the techniques. RESULTS: Thirteen trials met the inclusion criteria. There was a trend towards reduced pain with MLC compared with conventional LC, without reduction in opioid use. Patients in the MLC group had slightly reduced length of hospital stay, but there were no significant differences for return to activity. The two interventions were also similar in terms of operating times and adverse events, but MLC was associated with better cosmetic result (largely patient rated). There was a significantly greater likelihood of conversion to conventional LC or to open cholecystectomy in the MLC group than there was of conversion to open cholecystectomy in the conventional LC group [OR 4.71 (95% confidence interval 2.67-8.31), p < 0.00001]. CONCLUSIONS: The data included in this review suggest that reducing the size of trocar incision results in some limited improvements in surgical outcomes after LC. However, it carries a higher risk of conversion to conventional LC or open cholecystectomy.

A systematic review of randomized trials evaluating regional techniques for postthoracotomy analgesia.

BACKGROUND: Thoracotomy induces severe postoperative pain and impairment of pulmonary function, and therefore regional analgesia has been intensively studied in this procedure. Thoracic epidural analgesia is commonly considered the "gold standard" in this setting; however, evaluation of the evidence is needed to assess the comparative benefits of alternative techniques, guide clinical practice and identify areas requiring further research. METHODS: In this systematic review of randomized trials we evaluated thoracic epidural, paravertebral, intrathecal, intercostal, and interpleural analgesic techniques, compared to each other and to systemic opioid analgesia, in adult thoracotomy. Postoperative pain, analgesic use, and complications were analyzed. RESULTS: Continuous paravertebral block was as effective as thoracic epidural analgesia with local anesthetic (LA) but was associated with a reduced incidence of hypotension. Paravertebral block reduced the incidence of pulmonary complications compared with systemic analgesia, whereas thoracic epidural analgesia did not. Thoracic epidural analgesia was superior to intrathecal and intercostal techniques, although these were superior to systemic analgesia; interpleural analgesia was inadequate. CONCLUSIONS: Either thoracic epidural analgesia with LA plus opioid or continuous paravertebral block with LA can be recommended. Where these techniques are not possible, or are contraindicated, intrathecal opioid or intercostal nerve block are recommended despite insufficient duration of analgesia, which requires the use of supplementary systemic analgesia. Quantitative meta-analyses were limited by heterogeneity in study design, and subject numbers were small. Further well designed studies are required to investigate the optimum components of the epidural solution and to rigorously evaluate the risks/benefits of continuous infusion paravertebral and intercostal techniques compared with thoracic epidural analgesia.