Study and ethics
PONV, pain
Ethical approval for the study was granted by the Ethics Committee of Dalian Municipal Central Hospital (yn-2021-085-01). It has been registered with the Chinese Clinical Trial Regist (ChiCTR2200056344). The patient was included from February 2022 to September 2022. The written informed consent was obtained from all participants.This study was designed as an assessor-blinded parallel-group randomized controlled trial. It was conducted to evaluate whether opioid-free general anesthesia combined with ultrasound-guided ICPB can meet the needs of thyroid surgery. Besides, this combined strategy was compared with traditional opioid-based general anesthesia in terms of their effects on PONV and pain after thyroid surgery.