Regional anesthesia techniques and postoperative delirium: systematic review and meta-analysis.

INTRODUCTION: Postoperative delirium is a frequent occurrence in the elderly surgical population. As a comprehensive list of predictive factors remains unknown, an opioid-sparing approach incorporating regional anesthesia techniques has been suggested to decrease its incidence. Due to the lack of conclusive evidence on the topic, we conducted a systematic review and meta-analysis to investigate the potential impact of regional anesthesia and analgesia on postoperative delirium. EVIDENCE ACQUISITION: PubMed, Embase, and the Cochrane central register of Controlled trials (CENTRAL) databases were searched for randomized trials comparing regional anesthesia or analgesia to systemic treatments in patients having any type of surgery. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We pooled the results separately for each of these two applications by random effects modelling. Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to evaluate the certainty of evidence and strength of conclusions. EVIDENCE SYNTHESIS: Eighteen trials (3361 subjects) were included. Using regional techniques for surgical anesthesia failed to reduce the risk of postoperative delirium, with a relative risk (RR) of 1.21 (95% CI: 0.79 to 1.85); P=0.3800. In contrast, regional analgesia reduced the relative risk of perioperative delirium by a RR of 0.53 (95% CI: 0.42 to 0.68; P<0.0001), when compared to systemic analgesia. Post-hoc subgroup analysis for hip fracture surgery yielded similar findings. CONCLUSIONS: These results show that postoperative delirium may be decreased when regional techniques are used in the postoperative period as an analgesic strategy. Intraoperative regional anesthesia alone may not decrease postoperative delirium since there are other factors that may influence this outcome.

Optimal local anesthetic regimen for saddle block in ambulatory anorectal surgery: an evidence-based systematic review.

BACKGROUND: Ambulatory anorectal surgery requires an anesthetic of short duration but profound depth. Saddle block anesthesia (SBA) can provide dense sacral anesthesia with minimal motor blockade, but the ideal local anesthetic agent remains undefined. This systematic review aims to identify the optimal SBA regimen for ambulatory anorectal surgery. METHODS: We sought randomized trials examining SBA for ambulatory anorectal surgery and stratified patients into four subgroups according to local anesthetic type and dose: (1) longer acting, higher dose; (2) longer acting, lower dose; (3) shorter acting, higher dose; and (4) shorter acting, lower dose. Longer acting agents included bupivacaine and levobupivacaine; shorter acting agents included chloroprocaine, mepivacaine, and prilocaine. Lower dose was defined as ≤5 mg and ≤20 mg for longer and shorter acting local anesthetics, respectively. The primary outcome was time to discharge; secondary outcomes included times to sensory and motor block regression, urine voiding, and ambulation, as well as block success. RESULTS: A total of 11 trials (1063 patients) were included. Overall study quality and reporting consistency was poor. Doses ranged from 1.5-7.5 mg to 3-30 mg of longer and shorter acting local anesthetics, respectively. Hyperbaric local anesthetics were used in eight trials (953 patients, 86%). The median time to discharge appeared similar across all subgroups with an overall time of 182 (IQR 102) min. The use of long-acting, lower dose regimens was associated with a faster median time to motor block regression. Block success approached 99% among all trials. CONCLUSIONS: There is presently insufficient qualitative and quantitative evidence to identify an optimal SBA regimen for ambulatory anorectal surgery. Nonetheless, we found that doses as low as 1.5 and 3 mg of longer and shorter acting hyperbaric local anesthetics, respectively, can achieve effective and reliable SBA with timely hospital discharge. Despite similar discharge times, longer acting, lower dose local anesthetics may produce faster motor block regression following SBA for ambulatory anorectal surgery.

Analgesic efficacy of cannabinoids for acute pain management after surgery: a systematic review and meta-analysis.

BACKGROUND: Evidence regarding the role of cannabinoids in managing acute postoperative pain is conflicting. The purpose of this systematic review and meta-analysis was to determine the analgesic efficacy of perioperative cannabinoid compounds for acute pain management after surgery. METHODS: Original research articles evaluating the addition of cannabinoids to standard opioid-based systemic analgesia (Control) in the postoperative period were sought. Our primary outcomes were cumulative oral morphine equivalent consumption and rest pain severity at 24 hours postoperatively. We also assessed analgesic consumption in the postanesthesia care unit (PACU), pain scores in PACU, 6 and 12 hours postoperatively, and opioid-related and cannabinoid-related side effects, patient satisfaction, and quality of recovery as secondary outcomes. RESULTS: Eight randomized controlled trials (924 patients) and four observational studies (4259 patients) were analyzed and included. There were insufficient data to pool for quantification of differences in cumulative oral morphine equivalent consumption and rest pain severity at 24 hours postoperatively with the addition of cannabinoids in comparison to Control. Qualitative synthesis revealed no differences in cumulative oral opioid consumption or pain at rest 24 hours postoperatively with the addition of cannabinoids in comparison to Control. Patients receiving cannabinoids appeared to have an increased weighted mean difference 95% CI of pain at 12 hours by 0.83 cm (0.04 to 1.63) (p=0.04). Patients receiving cannabinoids also appeared to have 3.24 times increased odds of developing hypotension postoperatively (95% CI 1.12 to 9.36) (p=0.03). Qualitative and quantitative synthesis revealed no differences in any other secondary outcomes. CONCLUSIONS: Our quantitative and qualitative review of the literature suggests that the analgesic role of perioperative cannabinoid compounds is limited, with no clinically important benefits detected when cannabinoids are added to traditional systemic analgesics compared with traditional systemic analgesics alone. Notably, there appears to be a signal towards increased postoperative pain and hypotension associated with the addition of perioperative cannabinoids to traditional systemic analgesics. These results do not support the routine use of cannabinoids to manage acute postoperative pain at the present time.