Intravenous dexamethasone is the best prophylaxis against rebound pain after a nerve block

The edition in brief

Rebound pain is the price of a good block, and until now there has been no ranked answer to what prevents it. A network meta-analysis of 24 randomised trials in 2,130 patients across eight interventions put intravenous dexamethasone first, with a SUCRA of 0.91 and a judgement of definitely superior to control. Perineural dexamethasone and dexmedetomidine ranked highest for delaying onset and prolonging analgesia. Pre-emptive opioids were probably inferior to control — which is the finding most likely to change a habit. Certainty ranged from very low to moderate. A two-centre randomised trial in 58 women compared intrathecal morphine, lateral quadratus lumborum block and their combination after Caesarean delivery. The non-inferiority test on quality of recovery at 24 hours was inconclusive, but the block reduced resting pain at six hours by 2.9 points against morphine, and the combination reduced resting pain, coughing pain and worst pain at 24 hours. Pruritus was more common with the block, mostly mild. Duloxetine for hip and knee arthroplasty reduced pain across every timepoint measured, but by around 5 mm on a 100 mm scale — statistically significant and below the threshold usually taken as clinically meaningful. It reduced nausea and increased drowsiness. And an umbrella review of 24 ERAS guidelines identifies eight domains that are consistent across all of them.