Optimising post-operative pain management is crucial for recovery in orthopaedic surgery. Methadone has attracted interest due to its long half-life, N-methyl-D-aspartate -receptor antagonism and potential to reduce post-operative opioid consumption. Existing reviews combine multiple surgical populations, limiting applicability to orthopaedic settings. This protocol outlines a systematic review assessing the analgesic efficacy and safety of peri-operative methadone in adult and adolescent orthopaedic patients.

This review will include randomised controlled trials evaluating intravenous peri-operative methadone vs placebo or standard analgesic regimens in orthopaedic surgery. Primary outcomes are post-operative rescue opioid consumption and pain intensity within 72 hours. Secondary outcomes include adverse events, mobility scores and the length of hospital stay. If available data permit, a methadone dose–response pattern may be investigated. Searches will be conducted in MEDLINE (Ovid), Embase (Ovid), CINAHL, CENTRAL, Web of Science and ClinicalTrials.gov without date restrictions. Two reviewers will independently screen studies, extract data and assess risk of bias using the Cochrane risk-of-bias tool for randomised trials. When appropriate, random-effects meta-analysis methods will be performed. Certainty of evidence will be assessed using Grading of recommendations assesment, development and Evaluation (GRADE).

As this study uses previously published data, ethical approval is not required. Findings will be disseminated through a peer-reviewed publication and conference presentations.

CRD42025616291.

Cardiovascular disease (CVD) is the leading cause of mortality in patients undergoing chronic haemodialysis (HD). However, relatively few data exist regarding the influence of dialysis treatment on cardiac biomarkers such as high-sensitivity cardiac troponin I and T (hs-cTnI and hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), complicating their interpretation in the diagnosis of acute coronary syndrome and heart failure. This study aims to investigate the intradialytic kinetics of hs-cTnT, hs-cTnI and NT-proBNP, during HD and haemodiafiltration (HDF), in patients treated with chronic HD.

Single-centre, randomised, open-label, crossover study, comparing high-flux HD (FX 100 dialyser) and postdilution HDF (FX 1000 dialyser), regarding their potential clearance of hs-cTnI, hs-cTnT and NT-proBNP, in 24 stable patients treated with in-centre HD without acute CVD. The study will investigate changes in concentrations during and after high-flux HD and postdilution HDF and calculate reduction ratios, dialyser clearance and clearance by adsorption to the membrane of the selected cardiac biomarkers. Blood samples will be collected at baseline, after 10, 30, 60, 120, 180 and 240 min of dialysis and 30 min postdialysis. After 120 min of dialysis, dialysate will also be collected from the dialyser outlet line. The primary outcome is change from baseline in concentrations of hs-cTnI, hs-cTnT and NT-proBNP during high-flux HD and postdilution HDF.

The study has been approved by the North Denmark Region Committee on Health Research Ethics (N-20240016). Results will be published in an international peer-reviewed journal and disseminated at national and international research meetings.

NCT06526702.

Despite an increasing use of screens among preschool children and evidence suggesting potential adverse effects, there is a paucity of longitudinal research that aims to disentangle the multifaceted components of screen use and their unique associations with development. We present a protocol for a large-scale national longitudinal study with repeated measurements in Danish preschool children, with the aim of investigating the cross-sectional and cross-lagged longitudinal associations between screen use and psychological outcomes.

The Digital Child Study is a national prospective observational cohort of Danish preschool children. Baseline parent-report data collection commenced in 2024 via online questionnaires, and in total will include three time points over 1 year: baseline (age 4 years), and follow-ups at 6 and 12 months (ages 4.5 and 5 years). Participants were divided into two waves based on birth dates, starting in March and September 2024. Recruitment targeted parents and primary caregivers of all Danish children born between specific dates in 2020. Of 30 235 children whose parents were sent invitations, baseline questionnaire data were available for 11 690 (39%).

Children’s screen use was measured by detailed information of amount, content and timing of children’s screen use, and the broader context, incorporating parental mediation strategies, attitudes, motivations and practices. Cognitive and socioemotional developmental outcomes were measured using validated tools such as the Strengths and Difficulties Questionnaire, the Nordic Five-to-Fifteen parent questionnaire and the Behaviour Rating Inventory of Executive Function—Preschool Version. Questionnaire data will be linked to national social and health registries to enable long-term follow-up. Statistical analyses will include longitudinal modelling to explore associations between screen use and developmental outcomes, with sensitivity analyses for robustness. The study’s large sample size provides high statistical power to detect meaningful effects.

The study adheres to ethical research guidelines, ensuring voluntary participation, confidentiality and compliance with data protection laws, with approvals from relevant authorities. Findings will be disseminated through peer-reviewed publications, conferences and plain-language summaries to engage stakeholders and the broader community.