Innovative Use of a Pediatric Double-Lumen Central Venous Catheter as a Midline Substitute in Adults With Difficult Venous Access: A Report of Two Cases

Long-term venous access is a dictum in recently advanced therapeutics, offering innumerable treatment options. When the patients are critically sick, central lines provide access for inotropes, antibiotics, dialysis, and hyperoncotic medications. However, when the patients step down to the intermediate level, only a few safe options of venous access are left. Midline catheters are intermediate-length venous access devices (3-5 French, 8-25 cm) inserted into the deep upper extremity veins, such as the basilic or cephalic vein, to provide reliable access for patients requiring prolonged therapy. As it terminates in the peripheral venous system, midlines offer a safer alternative to central venous catheters (CVCs), minimizing risks of pneumothorax, thrombosis, and infection. Midline catheters provide durable peripheral venous access but may be unavailable in some hospitals. Pediatric CVCs are typically 3-5 French and 5-10 cm in length and share dimensional similarities with midline catheters, suggesting potential for adaptation in adults when standard options are lacking. These devices are widely available and can be a substitute when standard devices are unavailable. This strategy offers certain advantages, particularly in patients with difficult venous access who require more durable or higher-capacity intravenous (IV) therapy than what peripheral IVs can provide. We report two adults with difficult venous access, one with a neuromuscular disorder and hypercapnic respiratory failure and one with immune-mediated necrotizing myopathy and multiple prior central devices, in whom a 4-French (Fr), 8 cm, double-lumen pediatric CVC (Arrow^R CS-25402, Teleflex Medical Wayne, PA, USA) was inserted as a midline. Under real-time ultrasound guidance, the basilic vein was cannulated using a modified Seldinger technique, and the catheter was advanced with the tip positioned in the proximal basilic vein, distal to the axillary vein, consistent with midline standards. Both devices functioned without thrombosis, dislodgement, or catheter-related infection during the required intensive care unit (ICU) therapy. When patients require long-term stay, are hemodynamically stable, and require prolonged venous cannulation and standard midlines are unavailable, a size-matched pediatric CVC placed under ultrasound with a confirmed peripheral tip can provide safe, practical access. This approach offers a practical solution for many complex patients across diverse healthcare settings, potentially broadening venous access options where midline catheters are not routinely stocked. This off-label strategy should follow infection-prevention bundles, non-vesicant infusion limits, clear labeling, and documentation. Both single- and double-lumen pediatric CVCs may be considered where dimensional compatibility with midline specifications is ensured. Larger studies are warranted.