Unlike non-tunneled central venous catheters (CVCs), tunneled CVCs travel under the skin and terminate away from the venous access site. As such, tunneled CVCs can be in place for weeks to months, while the non-tunneled catheters must be exchanged every few days to a week. There are two major types of tunneled CVCs: those ending in a subcutaneous port and those that exit the skin as access catheters. The subcutaneous port typically has one or two lumens and ends in either a single or double port, respectively. This port is placed on the chest wall, under the skin and subcutaneous tissues. It is accessed via needle-stick to allow infusion of medication, intravenous fluids, and/or nutrition. It is never used for hemodialysis.
In contrast, the tunneled CVC without a subcutaneous port exits the skin at a distance from the venous puncture site. It has a cuff surrounding the catheter, which secures it within the subcutaneous tissues and comes in a variety of diameters and access ports. An additional benefit of this catheter is that it does not require recurrent needle-sticks for access. This type of central venous access can be used for nutrition, transfusion of fluids, infusion of medications, as well as hemodialysis. Placement of either tunneled catheter allows patients to continue intravenous therapy upon their discharge from the hospital.Reference:
Flick AI, Winters R. Vascular Tunneled Central Catheter Access. 2022 Jul 1. In: StatPearls . Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 32491546.