Efficacy of Mini-Midline Catheters and Risk Factors for Complications in Perioperative Thoracic Surgery Patients with Difficult Intravenous Access

Background: Perioperative patients with difficult intravenous access (DIVA) undergoing video-assisted thoracoscopic surgery (VATS) lung resection often require reliable short-term intravenous access. This study evaluated the clinical performance of ultrasound-guided mini-midline catheters (MMCs) and explored factors associated with MMC-related complications. Methods: In this single-center retrospective observational study, we reviewed the electronic medical records of consecutive DIVA patients who underwent elective VATS lung resection and received ultrasound-guided MMC insertion between November 2025 and February 2026. Data regarding procedural outcomes, catheter dwell time, and local/systemic complications were extracted from the Hospital Information System and nursing logs. Multivariable logistic regression was performed to identify risk factors for complications. Results: MMC insertion was successful in all 163 patients, with a first-attempt success rate of 82.8%. Mean dwell time was 7.03 ± 1.80 days. Complications occurred in 38 patients (23.3%), mainly phlebitis (11.7%) and puncture-site oozing (6.7%). No clinically suspected catheter-related bloodstream infection or symptomatic catheter-related thrombosis was observed. In multivariable analysis, fibrinogen at 24 h after insertion was independently associated with MMC-related complications (OR 1.855, 95% CI 1.36– 2.54, p < 0.001). Conclusion: Ultrasound-guided MMCs appear to be a feasible and relatively safe option for perioperative vascular access in DIVA patients undergoing VATS lung resection. Elevated fibrinogen at 24 h after insertion may help identify patients at higher risk of MMC-related complications.