Efficacy and safety of adjuvant intrathecal dexamethasone during spinal anesthesia: A systematic review and meta-analysis

The use of intrathecal (IT) dexamethasone during subarachnoid block (SAB) has not been evaluated. There are no pooled data available to decide on the optimal regimen of IT dexamethasone during SAB, irrespective of the type of surgery. There is uncertainty about its dosage, effectiveness, and safety, and a need to establish clear guidelines on its use. Our objective was to evaluate the effectiveness and safety of use of IT dexamethasone during SAB. We performed a meta-analysis (PROSPERO, CRD42022304944) of trials that included patients who underwent a variety of surgical procedures under SAB. Patients received concomitant IT dexamethasone as an adjuvant to spinal local anesthetics. The analyzed outcomes included sensory and motor effects as well as adverse and/or beneficial side effects. Subgroup analysis was planned based on different doses used. Trial sequential analysis (TSA) was used to estimate the required sample size information (RIS) for each outcome. Eighteen studies (2531 participants) were included in this analysis. Addition of IT dexamethasone (4-8 mg) to heavy bupivacaine effectively prolonged the duration of sensory blockade (mean difference, MD = 63.8 minutes; [95% confidence interval, CI, 33.1-94.5], P < 0.0001), two-segment regression time (MD = 20.1[95% CI, 0.96-39.2], P = 0.04) and first rescue analgesic time (MD = 143.3 [95% CI, 90.3-196.0], P = 0.001). Subgroup analyses revealed superior effects of 8 mg dose over 4 mg for sensory and analgesic effects. The effect of dexamethasone on duration of motor blockade was inconclusive. Additionally, lower risk ratios (RRs) were recorded for spinal anesthesia-related hypotension (RR = 0.74 [95% CI, 0.6-0.9], P = 0.0003) and nausea/vomiting (RR = 0.62 [95% CI, 0.41-0.93], P = 0.02) in the dexamethasone group. For outcomes such as sensory blockade, analgesia, and hypotension, the required information size was reached during TSA. In conclusion, IT dexamethasone, used as an adjuvant to spinal local anesthetic, especially at the dose of 8 mg, increases sensory blockade duration and the time for request of the first rescue analgesic. SAB-induced side effects such as hypotension, nausea, and vomiting are lesser with the use of IT dexamethasone. However, further studies are necessary to draw meaningful conclusions on its safety profile.