Postoperative regional anesthesia may decrease likelihood of delirium after surgery

Postoperative delirium (POD) is a syndrome characterized by altered mental state and acute attention difficulties that often develops within five days following surgery. The incidence of POD among older adult surgical patients ranges from 20% to 45%.

The patient's fragility and prior cognitive impairment may predispose him or her to acquire this condition. In addition to the use of opioids and hypnotics, surgical stress, pain, and a restriction in movement have been implicated in the etiology of this condition.

Recent systematic review and meta-analysis augment the previously published 2017 guidelines with an updated review of the evidence to study the risk of POD during the perioperative period and evaluate the possible effect of regional anesthesia and analgesia.

Patients undergoing any form of surgery were searched in PubMed, Embase, and the Cochrane central registry of Controlled trials (CENTRAL) databases for randomized studies comparing localized anesthetic or analgesia to systemic therapies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was followed for this systematic review and meta-analysis. Using random effects modeling, we aggregated the findings independently for each of these two applications. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the reliability of the evidence and the robustness of the findings.

There were 18 trials (3361 individuals) involved. Regional anesthetic failed to lower the incidence of postoperative delirium, with a relative risk (RR) of 1.21 (95% confidence interval [CI]: 0.79 to 1.80); P=0.3800. Compared to systemic analgesia, localized analgesia decreased the relative risk of perioperative delirium by 0.53 (95% CI: 0.42 to 0.68; P0.0001). A post-hoc subgroup study of hip fracture surgery produced comparable results.

This revised systematic review and meta-analysis supports the use of regional analgesia over systemic analgesia in the postoperative phase because to the lower risk of POD associated with regional analgesia. However, intraoperative regional anesthetic is not linked to a lower incidence of POD. This work contributes to the scientific literature since it is the first meta-analysis to date that investigates the use of regional anesthetic or analgesia during specified time periods and determines the differential influence on the risk of postoperative complications (POD). On the basis of this revised systematic review and meta-analysis, we may conclude that localized analgesia may lower the incidence of POD in surgical patients. Further high-quality RCTs should be conducted to define the peripheral block type and timing.

Important ideas

• Postoperative delirium (POD) remains a poorly understood and complex adverse event.

• It does not seem that intraoperative regional anesthetic alone affects the occurrence of POD.

• Postoperative regional analgesia may lower the occurrence of POD in patients following a variety of surgical procedures.

Reference –

Fanelli A, Balzani E, Memtsoudis S, Abdallah FW, Mariano ER. Regional anesthesia techniques and postoperative delirium: systematic review and meta-analysis. Minerva Anestesiol 2022;88:499-507. DOI: 10.23736/S0375-9393.22.16076-1