An adapter assembly for connecting a catheter assembly to a tunneler is disclosed. The adapter assembly has a generally tubular body having a first end, a second end and a longitudinal axis extending therethrough between the first end and the second end. The first end of the adapter is constructed to engage the proximal end of a trocar. The second end of the adapter is constructed to releasably engage at least one catheter lumen. A slider is disposed about the adapter and is longitudinally slidable along the adapter. When the slider is slid towards the second end of the adapter, the slider engages a plurality of legs on the adapter. The slider biases the plurality of legs toward each other and the longitudinal axis of the adapter. A method of subcutaneously tunneling a catheter using the adapter assembly is also described. The method comprises inserting a catheter into a patient, connecting the proximal end of a trocar to the adapter assembly, releasably restraining at least one lumen of the catheter in the adapter, and tunneling the assembly.