Impact of different tip locations of the midline catheter on complications: a systematic review and Bayesian network meta-analysis.

Background: Midline catheters (MCs) are widely used for short- to mid-term intravenous therapy, however, the impact of different tip locations on complications remains unclear. This study systematically evaluated the effect of MC tip position on complication risks to inform optimal placement strategies. Methods: We searched PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Chinese Scientific Journals Database (VIP) up to March 5, 2025, to identify observational and interventional studies comparing MC tip locations. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the National Institutes of Health (NIH) tool. Evidence quality was further evaluated with the Confidence in Network Meta-Analysis (CINeMA) framework. A Bayesian network meta-analysis (BNMA) in R (version 4.3.3) synthesized direct and indirect evidence, estimating relative risks (RRs) with 95% credible intervals (CrIs) and ranking tip locations via surface under the cumulative ranking curve (SUCRA). Sensitivity analyses were conducted using alternative model specifications and subsets of study designs to verify the robustness of the findings. Results: Nine studies involving 2,000 participants covered six tip locations, including the subclavian vein (SV) and brachiocephalic vein (BV). The results demonstrated that positioning the catheter tip in the SV was the most effective in reducing the risk of complications. Compared with the distal axillary vein (AV), the SV was associated with a statistically significant reduction in the risk of catheter-related thrombosis (CRT) (RR =0.36; 95% CrI: 0.13-0.92), catheter occlusion (RR =0.12; 95% CrI: 0.05-0.27), and phlebitis (RR =0.31; 95% CrI: 0.09-0.94). Although BV placement showed a lower risk of overall complications (RR =0.15; 95% CrI: 0.01-0.74; SUCRA =85.9%), it was based on limited evidence, resulting in wide CrIs and extreme estimates. Moreover, tip placement in the axillary-subclavian junction (ASVJ) was associated with a statistically significant increase in the risk of thrombosis (RR =26.88; 95% CrI: 4.74-237.30), indicating the potential risks of anatomical transition zones. Quality assessment indicated high confidence for phlebitis and overall complications, while catheter occlusion and thrombosis were rated at a moderate level. Heterogeneity was generally low across pooled analyses (I Conclusions: Our results indicated that positioning the MC tip in the SV may notably reduce the risks of CRT, catheter occlusion, phlebitis, and overall complications. In the future, the catheter materials and placement techniques should be standardized, and the short- and mid-term effect of tip placement in the SV should be investigated through prospective follow-up, which may enhance the framework of clinical decision-making.