IntroductionPulsed radiofrequency (PRF) ablation is commonly used for the treatment of neuropathic pain (NP). However, it is unclear whether increasing the output voltage of PRF can safely improve its efficacy. This study aims to compare the efficacy and safety of high-voltage PRF ablation and standard-voltage PRF ablation for the treatment of patients with NP.Methods and analysisWe will search PubMed/MEDLINE, EMBASE, Web of Science, the Cochrane Library, conference proceedings for relevant abstracts, clinical trials registers (ClinicalTrials.gov) and the WHO’s International Clinical Trial Registry Platform (from the date of inception until 15 March 2022). Only randomised controlled trials will be included. Two reviewers (YJ and GF) will independently perform study screening and selection, data extraction, risk-of-bias assessment and quality-of-evidence assessment. The primary outcome of this meta-analysis will be the efficiency rate in patients with NP. The secondary outcomes will include numeric rating scale score, visual analogue scale score, time to take effect, rescue drug dosage, quality of life using the health questionnaire (SF-36) and the incidence of adverse events. Meta-analyses will be conducted using standard meta-analysis software (RevMan V.5.3, The Nordic Cochrane Center, The Cochrane Collaboration, Copenhagen, Denmark).Ethics and disseminationThe requirement for ethical approval was waived as our systematic review will be based on the published literature. The results of this study will be submitted to a peer-reviewed journal.PROSPERO registration numberCRD42022297804.

Background: Norepinephrine is used to prevent anesthesia-related disorders in elderly patients. However, optimal dosage that improve the postoperative outcome undergone lumbar spinal fusion is unknown.Methods: A total of 108 elderly patients were randomized into three groups of norepinephrine infusion as 0.030 µg.kg− 1.min− 1, 0.060 µg.kg− 1.min− 1 and 0.090 µg.kg− 1.min− 1. The hemodynamics and related parameters were monitored at the entrance to the operation room (T0), 15 min following anesthesia induction (T1), 60 min after surgical incision (T2), and immediately after surgery (T3), respectively. The primary outcome was set as the incidence of postoperative complications and wound infections. The secondary outcomes were recorded by the incidence of nausea and vomiting, the time of first flatus, first ambulation, first intake and postoperative hospital stay.Results: Finally, 90 patients were recruited into the clinical trial, with 30 in each group. The incidence of delayed wound healing and infection were increase with the dose of 0.030 µg.kg− 1.min− 1 compared to others (0.030 µg.kg− 1.min− 1 vs. 0.060 µg.kg− 1.min− 1 vs. 0.090 µg.kg− 1.min− 1: 33.3% vs. 10% vs. 10%, P = 0.024; 26.7% vs. 6.7% vs. 6.7%, P = 0.031). Intraoperative total fluid volume and crystalloids, colloids volume in 0.030 µg.kg− 1.min− 1 group were significantly higher than 0.060 and 0.090µg·kg− 1·min− 1. The incidence of intraoperative hypotension effectively decreased in 0.060µg·kg− 1·min− 1 and 0.090µg·kg− 1·min− 1 compared to 0.030µg·kg− 1·min− 1(6.7%vs33.3%, P = 0.01, 3.3% vs. 33.3%, P = 0.003).The frequency of bradycardia in 0.090 µg.kg− 1.min− 1 group’s patients was significantly higher than that in the dosage 0.030 µg.kg− 1.min− 1 group (3%vs26%, P = 0.026) and 0.060 µg.kg− 1.min− 1 group (3% vs. 6.7%, P = 0.038). Patients with 0.060 µg.kg− 1.min− 1 had earlier first intaking by 1.4 hours and first flatus by 1.1 hours. Overall, Postoperative hospital stay was reduced by around 1 day in the 0.060 µg.kg− 1.min− 1 and 0.090 µg.kg− 1.min− 1 group among three groups (6.0 vs. 6.2 vs. 7.1days, P = 0.066).Conclusion: The 0.060 µg·kg− 1·min− 1 dosage of norepinephrine infusion combined with goal-directed fluid therapy can improve the elderly patients’ postoperative outcome and accelerate their rehabilitation process.Clinical Trial Registration: Identifier ChiCTR-1900021309, Registration date: September 19, 2018; www.chictr.org.cn.