Clinical study

Primary outcomes and anticipated effect sizes in randomized clinical trials assessing adjuncts to peripheral nerve blocks: a systematic scoping review

Peripheral nerve blocks are commonly used for peri- and postoperative analgesia. The duration of the block depends on the local anesthetic used, the type of block, and the anatomical placement of the block. However, adjuvant agents such as adrenaline, dexmedetomidine, buprenorphine, and other drugs can extend the duration of the block. It is desirable to prolong the duration of the block to decrease postoperative opioid consumption and to make it easier for patients to rehabilitate after surgery. Several randomized clinical trials have assessed the effects of adjuncts to peripheral nerve blocks, but the choices of primary outcomes and anticipated effect sizes are different between the trials. Heterogeneity in the choices of primary outcomes and anticipated effect sizes in RCTs in this area complicates meta-analysis in systematic reviews.

This scoping review will be conducted using The Cochrane Handbook, PRISMA-R and -ScR guidelines. The research protocol will be registered before conducting a systematic search of Medline, Embase, and Cochrane CENTRAL.

The scoping review aims to investigate the choices of primary outcomes and anticipated effect sizes in randomized clinical trials assessing adjuncts for peripheral nerve blocks in adult patients undergoing surgery. Thereby, the review will guide future choices of primary outcomes and anticipated effect sizes in RCTs assessing adjuncts for peripheral nerve blocks.